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POWR-GARD™ PRODUCTS CATALOG

Littelfuse®
The World’s Leading Provider of Circuit Protection Solutions
An Exceptional Portfolio
Littelfuse is committed to providing every one of our customers
with the right solutions to meet all of your circuit protection needs. Makes All the Difference
That is why we carry the broadest range of technologies available
When you work with Littelfuse, you are working with the broadest
on the market today.
and deepest circuit protection portfolio available. We leverage
The breadth of our offering, combined with our depth of product 7 different technologies, giving you access to an unparalleled
and application expertise, gives us the freedom to provide
selection – helping you find the right solution for your application.
objective, comprehensive solutions to meet the specific needs
• Fuses, Holders & Accessories
of each application. This allows for a true partnership with
our customers.
• PTCs
• GDTs

The Industries We Serve

• SIDACtors®
Solutions from Littelfuse can be found in virtually every application• Varistors
that uses electrical energy, including:
• Diodes
• Automotive applications
• Polymer ESD devices
• Digital consumer electronics
• Industrial/Electrical applications
• Telecom/Datacom circuits

Commitment to Circuit Protection
For over 75 years Littelfuse has maintained its focus on
circuit protection. As we expand in global reach and technical
sophistication, you can continue to count on us for solid circuit
protection solutions, innovative technologies, and industry-leading
expertise. It is a commitment that only a world-class leader with
staying power can support.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

Contents

POWR-PRO® Fuses
Indicator ® Introduction
Global Pro™ Introduction
MROplus™
POWR-PRO ® Introduction
KLPC
LLSRK_ID
LLNRK, LLSRK
JTD_ID
CCMR
IDSR
LDC

General Purpose Fuses
KLLU
FLNR_ID/FLSR_ID
FLNR/FLSR
KLNR/KLSR
NLN/NLS
RLN/RLS
JLS
JLLN/JLLS
SLC
CCMR, KLDR, KLKR
Plug Fuses

3
4
5
6
7
8-10
11-13
14-16
17-19
20-21
22
23-24

25
26-28
29-32
33
34-35
36-37
38
39-40
41-43
44
45-47
48

Special Purpose Fuses
Semiconductor Fuses
Fork-Lift Fuses
Cable Limiters
LMF, LGR, LHR

Blocks & Holders
Class H/K5 & R
Class J
Class T
Class G
Class CC & Midget
Class CC & Midget Accessories
POWR-SAFE Fuseholders
POWR-Covers
Pullers, POWR-JAW
571 Fuseholder
LFFB Limiter Block
LHFB Inline 3AG Holder
Semiconductor Blocks
POWR-BLOKS™
Distribution/Splicer
Dimensions
In-Line Watertight Fuseholders

Miscellaneous Products
Midget & Electronic Fuses
Midget Fuses
Electronic Fuses
3AG/3AB
Indicating
5x20 mm IEC Type
5x20 mm & 2AG
Subminiature
Automotive Fuses
SFE & Blade Type
Bolt-on Type
Miscellaneous Types

Medium Voltage Fuses
Medium Voltage Fuses

Telecom Products
L17T
TLN
TLS
70 Series
481 Series
LTFD 101
LTFD 6001
LTFD 1200

© 2005 Littelfuse • POWR-GARD™ Products Catalog

83
84-106
107
108
109

110
111-116
117-119
120-123
124
125-126
127
128-129
130
131
132
133
133
134-136
137-141
142-144
145-150

151

49
50-54
55
56
57
58
59
60
61
62

63
64-75

76
77
78
79
80
80
81
82
82

POWR-Switch and LPMP Panel
Disconnect Switches
Fuse Reducers
Box Covers
Fuse Cabinet, Display

International Products
Global Pro Fuses
Global Pro Fuseholders
NH Fuse Links
Diazed/Neozed Fuse
Cylindrical Fuses
British Dimension

Overvoltage Suppression Products
Introduction
Industrial Varistor Products
LVSP

Fuseology
Terms and Definitions
Electrical Safety
Fuse Application Guide
Motor Protection Tables
Condensed Cross Reference
Alphanumeric Index

www.littelfuse.com

152-155
156
157
158-159
160

161
162
163
164-165
166-167
168
169

170
171-172
173
174

175
177-181
182-183
184-203
204-206
207
208

1

POWR-PRO® Fuses

POWR-PRO® Fuses

UL Class

Fuse Overload
Characteristics

Interrupting
Rating, Amperes

AC Voltage Rating

Available Ampere
Ratings

Littelfuse Series
Number

Page Number

L

Time-Delay

200,000
300,000**

600

200 – 6000
601 – 4000
150 – 2000

KLPC**
KLLU
LDC*

8-10
26-28
23-24

Time-Delay

200,000
300,000**

250
600
600

1/10 – 600

LLNRK**
LLSRK**
LLSRK_ID**

14-16
14-16
11-13

Fast-Acting

200,000

250
600

1 – 600

KLNR
KLSR

34-35

RK5

Time-Delay

200,000
300,000**

250
600
600

1/10 – 600

FLNR/FLNR_ID**
FLSR/FLSR_ID**
IDSR**,*

29-32
29-32
22

T

Fast-Acting

200,000

300
600

1 – 1200

JLLN
JLLS

41-43

Time-Delay

200,000/300,000**

600

8/10 – 600

JTD/JTD_ID**

17-19

Fast-Acting

200,000

600

1 – 600

JLS

39-40

Time-Delay

200,000
300,000**

600

1/10 – 30
2/10 – 30

KLDR
CCMR**

45-47
20-21

RK1

J

CC

Fast-Acting

200,000

600

1/10 – 30

KLKR

45-47

CD

Time-Delay

200,000/300,000**

600

35 – 60

CCMR**

20-21

G

Time-Lag

100,000

600
480

1/2 – 20
25 – 60

SLC
SLC

44

K5

“One-Time” Fuses
Fast-Acting

50,000

250
600

1 – 600
1 – 600

NLN
NLS

36-37

H

Renewable Fuses
Fast-Acting
Time-Delay

10,000

250
600

1 – 600
1 – 600

RLN
RLS

38

Time-Delay

10,000

125

1/4 – 30

SOO, TOO

48

Medium Time-Delay

10,000

125

15 – 30

SLO, TLO

48

Supplementary

Midget Fuses
Electronic Fuses
Automotive Fuses

Varies

32 to 1000

1/10 – 30
1/500 – 30
1-250

See Product Listings

50-54
55-59
60-62

Telecommunications

Fast-Acting

100,000

170VDC

70 – 1200
1 – 600
1 – 70

L17T
TLN
TLS

77
78
79

Plug

* LDC and IDSR are rated 600 volts AC/DC.
** Series are UL Listed with I.R. of 200,000 amps and Littelfuse self-certified with 300,000A I.R.

2

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Littelfuse Indicator® Fuses

4

Littelfuse Global Pro™ System

5

Littelfuse MROplus™

6

Littelfuse POWR-PRO System

7

KLPC Series POWR-PRO Class L Fuses

8-10

LLSRK_ID Series Indicator POWR-PRO Class RK1 Fuses

11-13

LLNRK/LLSRK Series POWR-PRO Class RK1 Fuses

14-16

JTD_ID Series Indicator POWR-PRO Class J Fuses

17-19

CCMR Series POWR-PRO Class CC and CD Fuses

20-21

IDSR Series Indicator POWR-PRO Class RK5 Fuses

22

LDC Series POWR-PRO Class L Fuses

23-24

www.littelfuse.com

POWR-PRO® Fuses

Littelfuse Indicator® Fuses

POWR-PRO® Fuses

Complete Circuit Protection Plus Time Saving Indication.
Indicator fuses combat one of the most common and frustrating
obstacles to productivity: downtime. Every time a fuse opens and
production stops, money is wasted. Locating a blown fuse used to take
20 minutes or more. Blown Littelfuse Indicator fuses can be spotted
quickly and safely, while the power is turned off.
Now it couldn’t be easier to locate the blown fuse. Simply look at the
Indicator window. When the fuse blows, the window turns from clear
to dark instantly, indicating which fuse needs to be replaced without
headaches or hassles.

Use Indicator fuses and you can:
• Reduce Downtime
• Reduce Nuisance Opening
• Reduce Fuse Inventory
• Reduce Equipment Damage
• Reduce Accidents
• Reduce Housekeeping Headaches

The Indicator® Solution Software
These technologically advanced fuses feature solid-state designs that
improve overall performance and increase fuse life. When properly
applied, Indicator fuses provide superior protection and improved timedelay over conventional fuse designs. The patented solid-state overload
section provides consistent and reliable operation by eliminating moving
parts which are subject to fatigue. This provides longer fuse life by
eliminating needless fuse openings due to motor inrush currents. The
superior performance allows you to consolidate your inventories by
replacing older, conventional fuses which have limited performance
characteristics.

This easy to use software analyzes your plant
operations and calculates six areas of cost savings
when you use Indicator fuses.
To calculate your savings, call 1-800-TEC-FUSE
for a free copy of the Indicator Solution software.

LLSRK_ID see pages 11-13
• Class RK1
• 600 VAC
• Dual-Element, Time-Delay
• 1/10-600 Amperes
FLNR_ID/FLSR_ID see pages 29-32
• Class RK5
• 250/600 VAC
• Dual-Element, Time-Delay
• 1/10-600 Amperes
IDSR see page 22
• Class RK5
• 600 V AC/DC
• Dual-Element, Time-Delay
• 1/10-600 Amperes
JTD_ID see pages 17-19
• Class J
• 600 VAC
• Dual-Element, Time-Delay
• 8/10-600 Amperes
313_ID see page 56
• Electronic 3AG
• 125/32 VAC
• Slo-Blo®
• 1/2-10 Amperes

Blown
Good

4

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

Littelfuse Global Pro™ System

Introducing the Global Pro System
POWR-PRO® Fuses

Offering World Class Performance and Global Acceptance

The International Challenge

Global Acceptance – Total Protection

Engineers and equipment designers are faced with a dilemma when
choosing the right circuit protection for their globally distributed
equipment. They need to worry about which markets the product
will be used in, what appropriate electrical standards apply in each
of those markets, and what fuses should be used so that users can
find replacements easily. These can be daunting questions particularly
because some of this information often is not available to the engineer
when a particular piece of equipment is being designed.

The Littelfuse Global Pro circuit protection system combines fuses, fuse
holders and fusible disconnect switches in a simple, integrated package
designed to comply with UL and IEC requirements. The result is the
single best solution for your worldwide circuit protection needs. No
matter where your product is used, Global Pro will be accepted. More
significantly, it’s easy too! It meets universal voltage standards, offers
universal fuse sizes and uses universally understood product labels and
part numbers.

The Global Pro system resolves these design issues by incorporating
North American standards to fit internationally accepted IEC fuse
dimensions. This allows use of touchsafe fuseholders that can be used
in virtually any market and permits equipment to be easily adapted by
simply replacing the fuse with one that meets local standards. It’s that
simple.

Flexible Components
The components of the Global Pro system are vital to its revolutionary
performance, and the key component within the system is the fuse. The
Littelfuse Global Fuse is designed to offer UL Class J performance, but
with the compact size and the international compatibility associated with
fuses manufactured to IEC dimensions.

The benefits of the Global Pro system include:

More Protection In Less Space
•
•
•
•
•
•
•

Global acceptance
UL and IEC approval
Universal voltages
Touch-safe components
Integrated lockout/tagout device for compliance
Pin-indication
Design versatility for OEMs

Littelfuse Global Pro fuses are significantly smaller in size than 30 amp,
60 amp, and 100 amp Class J fuses. But their small size does not limit
their performance. All Global Pro fuses offer the following:
•
•
•
•

Extremely compact size
Pop-up indication
Performance to UL Class J fuse requirements
Compatibility with IEC style fuseholders

Note: For more information refer to pages 162–163 of this catalog.

Good

Blown

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

5

POWR-PRO® Fuses

TM

POWR-PRO® Fuses

Circuit Protection Simplified!

Cu s t

aly
y An
n tor
Inve
d
e
omiz

e po
sis R

r ts

The Littelfuse exclusive MROplus (Material Reduction Opportunity Plus)
program is designed to help lower costs, reduce inventory and improve
circuit protection performance. A team of Littelfuse technical experts will
analyze inventory and generate a variety of detailed reports including:
a total cost savings report, a cross reference report and a duplicate or
obsolete inventory report. On average, customers who use the Littelfuse
MROplus program are able to reduce their inventory by 28%. All you
have to do is supply a list of current inventory and the Littlefuse MROplus
program will do the rest. And, best of all, it is absolutely FREE!

Full C
olor

Pr e s e

ntatio

n Br oc
h

ur e

1
2
3
4

Your C
ustom
ized In
vento
r y An
alysi

s I s In
side

For more information call 1-800-TEC-FUSE
6

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

Littelfuse POWR-PRO® System

POWR-PRO® Fuses

The Littelfuse POWR-PRO
System of fuses gives you all
the fuses you need for complete
circuit protection coverage
while reducing inventory and
controlling costs.

The POWR-PRO System will:
• Provide superior current-limiting protection with innovative, tested
designs to prevent or reduce electrical system damage.
• Reduce inventory by standardizing system protection.
• Provide visual blown fuse indication with LLSRK_ID, and JTD_ID
Indicator® fuses.
• Reduce fuse replacement downtime with simple color coded fuse
labels.
See for yourself why the POWR-PRO System gives you the widest range
of circuit protection available today when compared to other systems.

Minimize Arc-Flash Hazards
Some of the factors that determine the severity of an Arc-Flash
are the magnitude of the fault current and the time the current is
allowed to flow. Current-limiting fuses applied within their currentlimiting range minimize the current flow and clear the fault in
0.00833 seconds or less. The more current-limiting the device
and the faster it clears the fault minimizes Arc-Flash hazards and
potentially reduces the amount of personal protective equipment
(PPE) required. Using Littelfuse POWR-PRO Fuses will not only
minimize Arc-Flash hazards with superior current limitation, but also
provide maximum protection to equipment.

UL Fuse Class

POWR-PRO®

Low Peak

System 2000

Class L

KLPC

KRPC

A4BQ

Class RK1

LLNRK/LLSRK_ID

LPNRK/LPSRK

A2DR/A6DR

Class J

JTD/JTD_ID

LPJ

AJT

Class CC

CCMR (2/10–60)

LPCC (1/2–30)

ATDR (0–30)

COLOR COORDINATED FOR EASE OF IDENTITY AND REPLACEMENT

One of the quickest and easiest ways to reduce Arc-Flash hazards is to
replace UL Class H, K5, and Class RK5 fuses with POWR-PRO currentlimiting Class RK1 or Class J fuses. For a given current and voltage
rating, Class H, K5, RK5, and RK1 fuses are the same physical size.
Therefore, it is easy to upgrade to better fuse protection and increased
safety. To insure that only the most current-limiting fuse is used, it
is recommended to change fuse clips to a rejection style for Class R
or Class J fuses. Class J fuses provides the best option by assuring
non-interchangeability with non-current-limiting fuses. Whichever
your choice, the equipment should be labeled to inform maintenance
personnel of the proper fuse replacement. The Littelfuse MROplusTM
Program can assist with analyzing and upgrading from non-currentlimiting fuses.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Green label fuses provide all
the inventory you need for:
• Superior current-limitation from
1/10 – 6000 amperes.
• Type 2 “No Damage”
coordination with NEMA and
IEC motor circuits.
• Blown fuse indication
(LLSRK_ID and JTD_ID).
• Compact protection for motor
circuits (JTD, JTD_ID, and
CCMR).
• 300,000 AIR to meet future
trends toward higher available
short circuit currents.

7

POWR-PRO® Fuses

KLPC Series POWR-PRO® Class L Fuses
600 VAC • Time-Delay • 200 – 6000 Amperes

POWR-PRO® Fuses

current and are also as current-limiting as the fastest Class L fuse on the
market. On average, the peak let-through currents of KLPC series fuses
are 10% less than any other time-delay Class L fuse.

Applications
Service switches
Switchboard mains and feeders
Bolted pressure contact switches
Motor control center mains
Large motor branch circuits
UL Listed series-rated protection for molded case circuit breaker
panelboards and loadcenters. (See panelboard manufacturers’
literature for recommended fuse rating.)
Primary and secondary protection for transformers
Protection of power circuit breakers

Features and Benefits

KLPC series POWR-PRO fuses provide ideal overcurrent protection
for circuits from 200 through 6000 amperes. KLPC series POWR-PRO
fuses specification-grade construction and performance meet or exceed
the most stringent project specifications: 99.9% pure silver links, silverplated copper end bells, glass-reinforced melamine bodies, O-ring seals
between body and end bells, and granular quartz fillers.
KLPC series POWR-PRO fuses are the only UL listed Class L fuses
that provide a minimum of ten seconds time delay at 500% rated

Specifications
Voltage Ratings:
Interrupting Ratings:

Ampere Range:
Approvals:

8

• Eliminate unnecessary downtime — KLPC POWR-PRO series timedelay withstands system surges and keeps your circuits in service.
• Best protection for system components — Maximum current
limitation means less equipment and system damage when short
circuits occur. Reduced damage means that electrical service can
be restored quickly, reducing costly downtime, and often permitting
equipment repair rather than replacement.
• Coordinates with other system components — KLPC series fuses
provide maximum coordination with fuses and circuit breakers both
on the line and load side of the fuses. See the Fuseology section of
this catalog for additional information.
• Eliminate need to oversize fuses — This may permit the use of smaller,
less expensive switches. Since lower rated fuses are more currentlimiting, equipment receives even better protection.
• 300kA Interrupting Rating — Littelfuse self-certified to 300,000
amperes as standard. Meets future trend towards higher available
short circuit currents.

Ampere Ratings
AC: 600 Volts
DC: 480 Volts
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
DC: 20,000 amperes
200 – 6000 amperes
AC: Standard 248-10, Class L
UL Listed 601 – 6000 amps
(File No: E81895)
UL Recognized 200 – 600 amps
(File No: E71611)
CSA Certified 200 – 6000 amps
(File No: LR29862)
QPL Federal Specifications WF-1814
700 – 6000 amps
DC: Littelfuse self-certified

200
250
300
350
400
450

500
600
601
650
700
750

800
900
1000
1100
1200
1300

1350
1400
1500
1600
1800
1900

2000
2100
2200
2300
2500
3000

3500
4000
4500
5000
6000

Example part number (series & amperage): KLPC 1000

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

KLPC Series POWR-PRO® Class L Fuses
600 VAC • Time-Delay • 200 – 6000 Amperes

POWR-PRO® Fuses

J
J
H

J

F

C B A

D E F

C B A

M

C B A

N
M

N
M

FIG.1

FIG.2

J
H

J
H

C B A

D E F

D E F

G

FIG. 3

A F

D B

L
K

N
M

G

G

FIG. 4

Amperes

Fig. No.

M

FIG. 5

A

B

C

53 ⁄4
(146.1)

63 ⁄4
(171.5)

D

Dimensions in Inches (mm in parentheses)
F
G
H
J
K

E

1

801 – 1200

2

33 ⁄4
(95.3)

53 ⁄4
(146.1)

63 ⁄4
91⁄ 4
(171.5) (235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

—

—

2
(50.8)

21⁄ 2
(63.5)

(9.5)

1201 – 1600

2

33 ⁄4
(95.3)

53 ⁄4
(146.1)

63 ⁄4
91⁄ 4
(171.5) (235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

—

—

23 ⁄8
(60.3)

3
(76.2)

(11.1)

1601 – 2000

2

33 ⁄4
(95.3)

53 ⁄4
(146.1)

63 ⁄4
91⁄ 4
(171.5) (235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

—

—

23 ⁄4
(69.9)

31⁄ 2
(88.9)

(12.7)

2001 – 2500

3

4
(101.6)

53 ⁄4
(146.1)

63 ⁄4
9 1⁄ 4
(171.5) (235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

15⁄ 8
(41.3)

13 ⁄ 4
(44.5)

31⁄ 2
(88.9)

5
(127.0)

(19.1)

2501 – 3000

3

4
(101.6)

53 ⁄4
(146.1)

63 ⁄4
9 1⁄ 4
(171.5) (235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

15⁄ 8
(41.3)

13 ⁄ 4
(44.5)

4
(101.6)

5
(127.0)

(19.1)

3001 – 4000

4

4
(101.6)

53 ⁄4
(146.1)

63 ⁄4
91⁄ 4
(171.5) (235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

13 ⁄ 4
(44.5)

31⁄ 4
(82.6)

43 ⁄ 4
(120.7)

53 ⁄4
(146.1)

(19.1)

5

4
(101.6)

53 ⁄4
(146.1)

—

10 3 ⁄ 4
(273.1)

15⁄ 8
(41.3)

31⁄ 4
(82.6)

51⁄ 4
(133.4)

71⁄ 8
(181.0)

1
(25.4)

5

4001 – 5000

4
(101.6)

3

3

5

1

3

1

1
(25.4)

5

5001 – 6000

5

5 ⁄4
(146.1)

—

91⁄ 4
(235.0)

—

—

1

—

© 2005 Littelfuse • POWR-GARD™ Products Catalog

9 ⁄4
(235.0)

—

10 ⁄ 4
(273.1)

1 ⁄8
(41.3)

—

2
(50.8)

21⁄ 2
(63.5)

(9.5)

3 ⁄4
(82.6)

5 ⁄4
(146.1)

www.littelfuse.com

7 ⁄8
(181.0)

3

M

200 – 800

—

8 5⁄ 8
(219.1)

L

3 3 ⁄4
(95.3)

⁄8

3

7

⁄8

⁄ 16

1

⁄2

3

3

3

⁄4
⁄4
⁄4

5

⁄ 8 x 11⁄8

(15.9) x (28.6)

N
—

5
⁄8 x 3 ⁄4
(15.9) X (19.1)

5
⁄8 x 11⁄ 8
(15.9) X (28.6)

5
⁄8 X 3 ⁄4
(15.9) X (19.1)

5
⁄8 X 11⁄ 8
(15.9) X (28.6)

5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄ 8 x 11⁄ 8
(15.9) x (28.6)

5
⁄8 X 3 ⁄4
(15.9) x (19.1)

5
⁄ 8 X 11⁄8
(15.9) x (28.6)

5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄ 8 x 11⁄8
(15.9) x (28.6)

5
⁄ 8 x 13 ⁄ 8
(15.9) x (34.9)

5
⁄8 x 13 ⁄8
(15.9) x (34.9)

⁄8 DIA.
(15.9)

⁄8 DIA.
(15.9)

—
—

9

POWR-PRO® Fuses

KLPC Series POWR-PRO® Class L Fuses
600 VAC • Time-Delay • 200 – 6000 Amperes

POWR-PRO® Fuses

Current-Limiting Effects of KLPC (600V) fuses
Apparent RMS Symmetrical Current for Various Fuse Ratings

Short Circuit Current*
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
80,000
100,000
150,000
200,000

800A

1200A

1600A

2000A

3000A

4000A

5000A

6000A

5,000
8,800
10,500
12,000
13,000
14,000
15,000
16,000
17,000
18,000
20,000
21,000
23,000
24,000

5,000
10,000
13,500
15,000
16,000
18,000
19,000
20,000
22,000
24,000
26,000
27,000
31,000
34,000

5,000
10,000
15,000
19,000
21,000
23,000
24,000
25,000
27,000
29,000
32,000
34,000
38,000
42,000

5,000
10,000
15,000
20,000
24,000
26,000
27,000
28,000
31,000
34,000
37,000
40,000
44,000
46,000

5,000
10,000
15,000
20,000
25,000
30,000
32,000
34,000
37,000
40,000
44,000
46,000
54,000
57,000

5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
42,500
46,000
51,000
57,000
67,000
70,000

5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
52,000
57,000
65,000
75,000
80,000

5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
70,000
75,000
87,000
95,000

1600A
2000A
2500A
3000A
3500A
4000A
5000A
6000A

1200A

800A

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data derived from Peak Let-Thru Curves

1000
800
600

1000000
800000
600000

400
300

400000
300000

200

100000
80000
60000

40
30

PEAK LET-THRU IN AMPERES

20

TIME IN SECONDS

6000A
5000A
4000A
3000A
2000A
1600A
1200A
800A

200000

100
80
60

10
8
6
4
3
2
1
.8
.6
.4
.3

40000
30000
20000
10000
8000
6000
4000
3000
2000
1000
800
600

.2
.1
.08
.06

400
300

.04
.03

200

.02

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

CURRENT IN AMPERES

10

200

100

600000
800000
1000000

300000
400000

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

200

100
80
100

50

.01

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

LLSRK_ID Series Indicator® POWR-PRO® Class RK1 Fuses
600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes

Applications
POWR-PRO® Fuses

All general purpose circuits
Motors
Transformers
Solenoids
Fluorescent lighting
All system components with high in-rush currents

Features/Benefits

The all new LLSRK_ID series fuse is the most advanced Class RK1
fuse available today providing unparalleled performance and protection
to modern circuits. The patented Indicator technology provides instant
identification of a blown fuse greatly enhancing system up-time, while
the precision formed short-circuit elements virtually eliminate damage
to components from unexpected electrical faults. In addition, the all new
solid-state overload section has no moving parts, stopping unnecessary
fatigue failures commonly found in other spring loaded fuses.

Specifications
Voltage Rating:
Interrupting Ratings:

Ampere Range:
Approvals:

• Reduce downtime — The indicating window of the LLSRK_ID
immediately identifies the open fuse. If the indicating strip is black,
the fuse has opened. It’s that simple. Maintenance personnel can
immediately determine that there is an open fuse.
• Reduce fuse inventory — The superior performance of the LLSRK_ID
allows it to be used in a variety of applications, thus decreasing fuse
inventory.
• Reduce nuisance opening — Indicator fuses offer superior time-delay
and cycling characteristics, which can lengthen fuse life.
• Reduce equipment damage — Indicator fuses provide superior
overload and short-circuit protection that can reduce equipment
damage. The LLSRK_ID is extremely current-limiting and provides
IEC Type 2 “No Damage” protection to IEC and NEMA type motor
starters.
• Reduce accidents — The LLSRK_ID Indicator fuse improves safety
by minimizing exposure to live circuits. Unlike other forms of blown
fuse indication, once the indicating strip darkens, it stays dark. Other
forms of indication require the power to remain on, which causes a
potential safety hazard to personnel.

Ordering Information
For online ordering use part number LSRK.

Ampere Ratings
600 VAC/300 VDC
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
DC: 20,000 amperes
1/10 – 600 amperes
AC: Standard 248-12, Class RK1
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
DC: Littelfuse self-certified

1

⁄ 10
⁄ 100
2
⁄10
1
⁄4
3
⁄ 10
4
⁄ 10
1
⁄2
6
⁄10
8
⁄10

15

1
11⁄8
11⁄4
14 ⁄ 10
16 ⁄10
18 ⁄ 10
2
21⁄4
21⁄2

28 ⁄ 10
3
32 ⁄10
31⁄2
4
41⁄ 2
5
5 6 ⁄10
6

61⁄4
7
8
9
10
12
15
171⁄2
20

25
30
35
40
45
50
60
70
75

80
90
100
110
125
150
175
200
225

250
300
350
400
450
500
600

Example part number (series & amperage): LLSRK30ID.
NOTE: All fuses rated 1 amp and above are Indicator fuses.

Recommended Fuse Blocks
LR600 Series
Refer to the Blocks & Holders section of this catalog for
additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

11

POWR-PRO® Fuses

LLSRK_ID Series Indicator® POWR-PRO® Class RK1 Fuses

POWR-PRO® Fuses

600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes

Plated End Caps

Blown Fuse Indicator Assembly

Precision Formed Short Circuit Element

Fiberglass Reinforced Pultruded Body

60A

30A
35A

12A
15A

Elastomeric Silicone Overload Section

5A

1A
1.25A
1.6A
2A
2.8A
3.5A

Granular Quartz Filling

1000

10
TIME IN SECONDS

TIME IN SECONDS

100

1

0.1

0.01
0.5

1

10

100

1000 2000

CURRENT IN AMPERES

CURRENT IN AMPERES

Contact Littelfuse for additional fuse curves.
12

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

LLSRK_ID Series Indicator® POWR-PRO® Class RK1 Fuses
600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes
Current-Limiting Effects of LLSRK_ID (600V) Fuses
POWR-PRO® Fuses

Apparent RMS Symmetrical Current for Various Fuse Ratings

Short Circuit Current*
30A

60A

100A

200A

400A

600A

5,000

1,060

1,600

2,100

2,600

4,100

--

10,000

1,350

2,000

2,800

3,400

5,250

8,000

15,000

1,600

2,300

3,200

3,900

6,000

9,000

20,000

1,700

2,600

3,600

4,500

6,700

10,000

25,000

1,900

2,800

3,800

4,800

7,500

11,000

30,000

2,000

3,000

4,100

5,200

8,000

12,000
12,500

35,000

2,100

3,100

4,400

5,700

8,500

40,000

2,200

3,300

4,600

6,000

9,000

13,000

50,000

2,400

3,500

4,900

6,500

9,500

14,000

60,000

2,500

3,800

5,200

7,000

10,000

15,000

80,000

2,700

4,000

5,700

7,750

11,000

17,000

100,000

2,900

4,200

6,200

8,500

12,000

18,000

150,000

3,200

4,600

7,300

10,000

14,000

21,000

200,000

3,300

4,700

8,000

11,000

16,000

23,000

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data derived from Peak Let-Thru Curves

1000000

60A

10000

30A
12A
5A
3.5A

PEAK LET-THRU IN AMPERES

PEAK LET-THRU IN AMPERES

100000

© 2005 Littelfuse • POWR-GARD™ Products Catalog

200000

AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

100000

10000

100

100

1000

1000

AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

www.littelfuse.com

13

POWR-PRO® Fuses

LLNRK/LLSRK Series POWR-PRO® Class RK1 Fuses
250/600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes

POWR-PRO® Fuses

Littelfuse LLNRK and LLSRK series POWR-PRO fuses provide superior
overload and short-circuit protection for service entrance, main, feeder
and general-purpose branch circuits up to 600 amperes.
LLNRK/LLSRK series fuses can be installed in existing Class H fuse
blocks to upgrade systems containing lower interrupting rating Class H
one-time or renewable fuses.

Applications
All general purpose circuits
Motors
Transformers
Solenoids
Fluorescent lighting
All system components with high in-rush currents

Features/Benefits
• Extremely current-limiting — Reduces damage to circuits and
equipment under short-circuit conditions. Stops damaging shortcircuits faster than any mechanical protective device.
• 300kA Interrupting Rating — Littelfuse self-certified to 300,000
amperes as standard. Meets future trend towards higher available
short-circuit currents.
• Reduced costs — Current-limiting design often permits use of readily
available, less costly equipment. Low resistance design reduces
power consumption and utility bills.
• Excellent time-delay — True dual-element construction, with separate
non-fatiguing thermally-reversible spring-loaded thermal overload
element, withstands repeated surges within rated time delay without
opening needlessly. Eliminates needless downtime caused by power
surges or equipment demands.

Specifications
Voltage Ratings:

Interrupting Ratings:

Ampere Range:
Approvals:

Ampere Ratings
AC: 250 Volts (LLNRK)
600 Volts (LLSRK)
DC: 125 Volts (LLNRK)
300 Volts (LLSRK)
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
DC: 20,000 amperes
1/10 – 600 amperes
AC: Standard 248-12, Class RK1
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
QPL: Federal Specification No. WF-1814
DC: Littelfuse self-certified

1

⁄10
1
28 ⁄10
61⁄4
25
80
1
⁄100
1 ⁄8
3
7
30
90
2
⁄10
11⁄4
32 ⁄10
8
35
100
1
⁄ 4*
14 ⁄10
3 1⁄2
9
40
110
3
⁄10
16 ⁄10
4
10
45
125
4
⁄10
18 ⁄10
41⁄ 2
12
50
150
1
⁄2
2
5
15
60
175
6
⁄10
21⁄4
5 6 ⁄10
171⁄2
70
200
8
⁄10
21⁄2
6
20
75*
225
* LLSRK Only.
Example part number (series & amperage): LLNRK 450.
For online ordering, use numbers LNRK and LSRK for LLNRK/LLSRK.
15

250
300
350
400
450
500
600

Recommended Fuse Blocks
LR250 series (LLNRK Series)
LR600 series (LLSRK Series)
Refer to the Blocks & Holders section of this catalog for additional information.

14

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

LLNRK/LLSRK Series POWR-PRO® Class RK1 Fuses
250/600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes
A

A

F

K
B

D

F

B
J

C

70-600A

FIG. 1
Refer to
Fig. No.

1/10 – 30

LLNRK
LLSRK
LLNRK
LLSRK
LLNRK
LLSRK
LLNRK
LLSRK
LLNRK
LLSRK
LLNRK
LLSRK

35 – 60

1

70 – 100

2

110 – 200

2

225 – 400

2

450 – 600

2

FIG. 2
Dimensions in Inches (mm in parentheses)

Series

1

A

B

2 (50.8)
5 (127.0)
3 (76.2)
51⁄ 2 (139.7)
57⁄ 8 (149.2)
77⁄ 8 (200.0)
71 ⁄ 8 (181.0)
9 5 ⁄ 8 (244.5)
8 5 ⁄ 8 (219.1)
115 ⁄ 8 (295.3)
10 3 ⁄ 8 (263.5)
133 ⁄ 8 (339.7)

C

1

⁄2 (12.7)
3
⁄4 (19.1)
3
⁄4 (19.1)

1

D

⁄2 (12.7)
5
⁄8 (15.9)
5
⁄8 (15.9)
5
1 (25.4)
⁄8 (15.9)
1 (25.4)
11 ⁄ 16 (27.0)
11 ⁄ 4 (31.8) 11 ⁄ 16 (27.0)
11⁄ 2 (38.1) 115 ⁄ 32 (37.3)
13 ⁄ 4 (44.5) 115 ⁄ 32 (37.3)
2 (50.8) 115 ⁄ 16 (49.2)
2 (50.8)
2 1⁄ 2 (63.5)
2 1⁄ 2 (63.5) 2 3 ⁄ 8 (60.3)
3 (76.2) 213 ⁄ 32 (61.1)

9

⁄ 16 (14.3)
3
⁄16 (20.6)
3
⁄16 (20.6)
11 ⁄ 16 (27.0)
11 ⁄ 16 (27.0)
15 ⁄ 16 (33.3)
119 ⁄ 32 (40.5)
127⁄ 32 (46.8)
23 ⁄ 32 (53.2)
219 ⁄ 32 (65.9)
219 ⁄ 32 (65.9)
33 ⁄ 32 (78.6)

LLNRK

E

F

5

3
⁄32 (4.0)
⁄ 8 (9.5)
3
5
⁄ 16 (4.8)
⁄8 (15.9)
3
5
⁄ 16 (4.8)
⁄8 15.9)
1
7
⁄4 (6.4)
⁄ 8 (22.2)
3
⁄4 (19.1)
11 ⁄ 4 (31.8)
3
⁄4 (19.1)
11⁄ 2 (38.1)
11⁄ 8 (28.6) 127⁄ 32 (46.8)
11⁄ 8 (28.6) 23 ⁄ 32 (53.2)
15 ⁄ 8 (41.3) 211 ⁄ 32 (59.5)
15 ⁄ 8 (41.3) 2 27⁄ 32 (72.2)
2 (50.8) 2 27⁄ 32 (72.2)
2 (50.8) 311 ⁄ 32 (84.9)

H

J

K

—

—

—

—

—

—

—

—
—

—

—

1

⁄4 (6.4)
1
⁄4 (6.4)
7
⁄ 16 (11.1)
7
⁄ 16 (11.1)
5
⁄8 (15.9)
5
⁄8 (15.9)
3
⁄4 (19.1)
3
⁄4 (19.1)

—

9

⁄32 (7.1)
9
⁄32 (7.1)
9
⁄32 (7.1)
9
⁄32 (7.1)
13
⁄ 32 (10.3)
13
⁄ 32 (10.3)
17
⁄ 32 (13.5)
17
⁄ 32 (13.5)

1

⁄2 (12.7)
1
⁄2 (12.7)
11
⁄16 (17.5)
11
⁄16 (17.5)
15
⁄16 (23.8)
15
⁄16 (23.8)
11⁄ 8 (28.6)
11⁄ 8 (28.6)

400
300

200

200

100
80
60

100
80
60

40
30

40
30

20

20

10
8
6

10
8
6

CURRENT IN AMPERES

400A
600A

100A

200A

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

5

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

.01

2000

.01

600
800
1000

.02

300
400

.04
.03

.02

200

.04
.03

60
80
100

.1
.08
.06

30
40

.1
.08
.06

20

.2

8
10

.4
.3

.2

200

1
.8
.6

.4
.3

© 2005 Littelfuse • POWR-GARD™ Products Catalog

60A

2

60
80
100

1
.8
.6

30
40

2

4
3

20

4
3

8
10

TIME IN SECONDS

400
300

30A

15A

400A
600A

200A

100A

60A

30A

15A

LLSRK

1000
800
600

5

G

5

⁄64 (2.0)
3
⁄32 (2.4)
3
⁄32 (2.4)
3
⁄32 (2.4)
1
⁄8 (3.2)
1
⁄ 8 (3.2)
3
⁄ 16 (4.8)
3
⁄ 16 (4.8)
1
⁄4 (6.4)
1
⁄4 (6.4)
1
⁄4 (6.4)
1
⁄4 (6.4)

1000
800
600

TIME IN SECONDS

G

H

E

Amperes

D

POWR-PRO® Fuses

G

E

C

CURRENT IN AMPERES

www.littelfuse.com

15

POWR-PRO® Fuses

LLNRK/LLSRK Series POWR-PRO® Class RK1 Fuses
250/600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes

Short
Circuit
Current*
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
80,000
100,000
150,000
200,000

Apparent RMS Symmetrical for Various Fuse Ratings
30A

60A

100A

200A

400A

600A

900
1,100
1,250
1,400
1,500
1,600
1,700
1,800
1,900
2,000
2,200
2,300
2,500
2,600

1,400
1,900
2,100
2,400
2,600
2,800
2,850
3,000
3,200
3,500
3,900
4,000
4,500
4,800

2,000
2,700
3,100
3,500
3,900
4,000
4,300
4,600
4,800
5,200
5,700
6,000
6,700
7,000

2,700
3,500
4,200
4,600
5,000
5,250
5,500
5,800
6,300
6,700
7,200
8,100
9,100
9,700

4,800
6,200
7,000
8,000
8,300
9,000
9,500
9,800
10,200
11,000
12,200
12,700
14,000
15,000

5,000
8,500
9,500
10,800
11,500
12,000
12,500
13,500
14,000
15,000
16,000
17,000
19,000
20,000

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data derived from Peak Let-Thru Curves

Short
Circuit
Current*
5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
80,000
100,000
150,000
200,000

Apparent RMS Symmetrical for Various Fuse Ratings
60A

100A

200A

400A

600A

1,060
1,350
1,600
1,700
1,900
2,000
2,100
2,200
2,400
2,500
2,700
2,900
3,200
3,300

1,600
2,000
2,300
2,600
2,800
3,000
3,100
3,300
3,500
3,800
4,000
4,200
4,600
4,700

2,100
2,800
3.200
3,600
3,800
4,100
4,400
4,600
4,900
5,200
5,700
6,200
7,300
8,000

2,600
3,400
3,900
4,500
4,800
5,200
5,700
6,000
6,500
7,000
7,750
8,500
10,000
11,000

4,100
5,250
6,000
6,700
7,500
8,000
8,500
9,000
9,500
10,000
11,000
12,000
14,000
16,000

—
8,000
9,000
10,000
11,000
12,000
12,500
13,000
14,000
15,000
17,000
18,000
21,000
23,000

LLSRK

1000000
800000
600000

1000000
800000
600000

400000
300000

400000
300000

200000

200000

100000
80000
60000

100000
80000
60000

4000
3000

200000

60000
80000
100000

200000

60000
80000
100000

30000
40000

20000

100
6000
8000
10000

100
3000
4000

200

2000

200

600
800
1000

400
300

300
400

400
300

200

1000
800
600

100

1000
800
600

30000
40000

2000

20000

2000

30A

6000
8000
10000

4000
3000

10000
8000
6000

3000
4000

30A

100A
60A

2000

10000
8000
6000

20000

600
800
1000

60A

300
400

100A

400A
200A

200

200A

20000

600A

40000
30000

100

600A
400A

40000
30000

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

16

30A

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data derived from Peak Let-Thru Curves

LLNRK

PEAK LET-THRU IN AMPERES

Current-Limiting Effects of LLSRK (600V) fuses

PEAK LET-THRU IN AMPERES

POWR-PRO® Fuses

Current-Limiting Effects of LLNRK (250V) fuses

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

JTD_ID Series Indicator® POWR-PRO® Class J Fuses
600 VAC • Time Delay • 8/10 – 600 Amperes

Applications
POWR-PRO® Fuses

Fused combination motor controllers to provide IEC Type 2 (“No
Damage”) motor branch circuit short-circuit and ground fault
protection
Motor control centers
Transformer protection
Protection for UL Listed series rated molded case circuit breaker panels
General purpose circuits — mains, feeders and branch circuits —
especially when space is limited.

Features/Benefits

The Littelfuse POWR-PRO JTD_ID Indicator Class J fuse provides visual
blown fuse indication and maximum protection in a compact package.
The compact Class J package was designed specifically for circuits
where space is at a premium. The current-limiting time delay JTD_ID
offers a patented, true dual-element design that is ideal for use in circuits
with high, in-rush currents. The Superior performance characteristics of
JTD_ID Indicator fuses reduce nuisance fuse opening, and the blown
fuse indication reduces downtime while increasing safety.

Specifications
Voltage Ratings:

Interrupting Ratings:

Ampere Range:
Approvals:

• Reduce downtime — A glance at the indicating window of a JTD_ID
Indicator fuse pinpoints open fuses immediately. If the indicating
window is dark, the fuse has opened. It’s that simple.
• Reduce nuisance opening — Indicator fuses have superior time-delay
and cycling characteristics which can lengthen fuse life and decrease
needless opening.
• Reduce fuse inventory — JTD_ID Indicator fuses have superior
performance characteristics, which means they can be used on a
variety of applications; therefore, decreasing fuse inventory.
• Reduce equipment damage — Indicator fuses provide superior
overload and short-circuit protection that can reduce equipment
damage. Indicator fuses also provide IEC Type 2 “No Damage”
protection to IEC and NEMA type motor starters.
• Reduce accidents — The JTD_ID Indicator fuse improves safety
by minimizing exposure to live circuits. Unlike other forms of blown
fuse indication, once the indicating window darkens, it stays dark. It
does not matter if the power is on or off or if the fuse is in a tool box.
Other forms of indication require the power to remain on, which is a
safety hazard for personnel.

Ampere Ratings
AC: 600 Volts
DC: 300 Volts ( 8 ⁄10 – 100A)
500 Volts (110 – 600A)
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
8/10 – 600 amperes
AC: Standard 248-8, Class J
ULListed (File No: E81895)
CSA Certified (File No: LR29862)
DC: Littelfuse self-certified
8
⁄10 - 100A: 300VDC self certified
110 – 600A: 500VDC self certified

8

⁄10
1
1 1⁄4
1 1⁄2
16 ⁄10
1 8 ⁄10
2
2 1⁄4
2 1⁄2

2 8 ⁄10
3
3 2 ⁄10
3 1⁄2
4
4 1⁄2
5
5 6 ⁄10
6

7
8
9
10
12
15
17 1⁄2
20
25

30
35
40
45
50
60
70
80
90

100
110
125
150
175
200
225
250
300

350
400
450
500
600

Example part number (series & amperage): JTD 60 ID

Recommended Fuse Blocks
LJ600 series, LPSJ series
Refer to Blocks & Holders section of this catalog for additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

17

POWR-PRO® Fuses

JTD_ID Series Indicator® POWR-PRO® Class J Fuses
600 VAC • Time-Delay • 8/10 – 600 Amperes

POWR-PRO® Fuses

An Inside Look . . .
Superior Short-Circuit Elements

Plated End Caps

Reduce damage to equipment and enables
the Littelfuse JTD_ID to provide IEC Type 2
“No Damage” protection to IEC and NEMA
motor starters.

Help reduce corrosion and provide superior
contact for lower heat generation.

Blown Fuse Indicator
Stone-Sand Filler

Incorporates precision wound elements to
provide consistent and reliable blown fuse
indication.

Helps provide I2t and Ipeak values well below
UL maximum limits and improves heat
dissipation and reliability.

Solid State Overload Section
Patented thermally reversible design utilizes
high-tech aircraft grade polymers to ensure
reliable operation every time.

Elastomeric Silicone EPR Plug
A space-age material used in the patented
overload section of the Littelfuse JTD_ID.

Granular Quartz Filler
Assists in quenching the arc that occurs during
overload conditions.

C
D

G

A

F
H

A
E

B
D

FIG. 1

18

FIG.2

Dimensions in Inches (mm in parentheses)

Amperes

Refer to
Fig. No.

A

B

8/10– 30

1

21⁄ 4 (57.2)

—

1

⁄ 2 (12.7)

13

35 – 60

1

2 3 ⁄ 8 (60.3)

—

5

⁄8 (15.9)

11 ⁄ 16 (27.0)

5

5

C

D

⁄16 (20.6)

5

E

F

G

H

—

—

—

—

—

—
3

—

—

70 – 100

2

2 ⁄ 8 (66.7)

3 ⁄ 8 (92.1)

—

4 ⁄ 8 (117.5)

1 ⁄ 8 (28.6)

⁄4 (19.1)

9

110 – 200

2

3 (76.2)

43 ⁄ 8 (111.1)

—

5 3 ⁄ 4 (146.1)

15 ⁄ 8 (41.3)

11⁄ 8 (28.6)

9

225 – 400

2

33 ⁄ 8 (85.7)

51 ⁄ 4 (133.4)

—

71 ⁄ 8 (181.0)

21 ⁄ 8 (54.0)

15 ⁄ 8 (41.3)

13

⁄ 32 (10.3)

1

450 – 600

2

33 ⁄ 4 (95.3)

6 (152.4)

—

8 (203.2)

2 5 ⁄ 8 (66.7)

2 (50.8)

17

⁄ 32 (13.5)

3

www.littelfuse.com

1

⁄32 (7.1)

1

⁄32 (7.1)

3

⁄ 8 (3.2)

⁄16 (4.8)
⁄4 (6.4)
⁄8 (9.5)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

JTD_ID Series Indicator® POWR-PRO® Class J Fuses
600 VAC • Time-Delay • 8/10 – 600 Amperes
Current-Limiting Effects of JTD_ID (600V) fuses

5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
80,000
100,000
150,000
200,000

POWR-PRO® Fuses

Short Circuit
Current*

Apparent RMS Symmetrical for Various Fuse Ratings
15A
565
675
775
825
900
950
1,000
1,050
1,100
1,200
1,300
1,375
1,500
1,600

30A
750
925
1,050
1,125
1,200
1,300
1,350
1,400
1,500
1,600
1,700
1,800
2,000
2,175

60A
1,500
1,900
2,100
2,300
2,500
2,600
2,700
2,800
3,000
3,200
3,400
3,600
3,950
4,000

100A
1,800
2,450
2,800
3,000
3,300
3,500
3,700
3,900
4,200
4,500
4,900
5,200
6,000
6,500

200A
2,800
3,600
4,100
4,400
5,000
5,100
5,400
5,600
6,000
6,400
7,200
7,800
9,000
10,000

400A
4,800
5,700
6,500
7,250
8,000
8,400
9,000
9,200
10,000
10,500
11,200
12,200
14,500
16,000

600A
5,000
7,750
9,000
9,700
10,500
11,000
12,000
12,500
13,000
14,000
15,500
16,500
19,000
20,500

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data derived from Peak Let-Thru Curves

PEAK LET-THRU IN AMPERES

1000000

100000

600A
400A
200A
100A
60A

10000

30A
15A
12A
5.6A
1000

100
100

1000

10000

100000 200000

AVAILABLE FAULT
SYMMETRICAL R.M.S. AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

19

POWR-PRO® Fuses

CCMR Series POWR-PRO® Class CC and CD Fuses
600 VAC • Dual-Element, Time-Delay • 2/10 – 60 Amperes

POWR-PRO® Fuses

circuits than would be possible if using fast-acting fuses. CCMR series
fuses provide superior protection in a fraction of the space required by
other fuse classes. For example, when 600V three pole, 30 ampere Class
R fuse blocks are replaced by Littelfuse Class CC fuse blocks, mounting
space requirements may be reduced 70% or more. This is especially
important when a panel contains control devices for many motors.
In addition to the UL Listed smaller sizes, Littelfuse CCMR series fuses
are now available in larger sizes — from 35 to 60 amperes! No other

fuse is available with this current carrying capacity in a package
this small. In fact, the 60 ampere CCMR fuse is the smallest 60A
fuse available rated at 600 volts.

Applications
CCMR series fuses are specifically designed to withstand sustained
starting currents of small motors
Provide short-circuit protection for motor branch circuits
Use with IEC- and NEMA-rated motor controllers and contactors
General purpose circuits up to 60 amps

Features/Benefits
For space saving protection of motor circuits up to 40 HP*, we
recommend Littelfuse POWR-PRO CCMR series fuses. These fuses
are the only true dual-element, time-delay fuses that come in a small
package specifically engineered for motor branch circuit protection.
CCMR series fuses provide Type 2 “No Damage” protection to both
NEMA-rated and the more sensitive IEC (International Electrotechnical
Commission) type motor circuit components.
Rating for rating, CCMR fuses are the most current-limiting fuses
available. They also provide superior short-circuit protection since their
time-delay characteristics permit the use of smaller fuse ratings in motor

• Space savings — No other fuse class approved for branch circuit
protection has a 600 volt rating and 300,000 A.I.R. in such a small
package.
• Extremely current-limiting — Reduces damage caused by heating
and magnetic effects of short-circuit currents. Stops damaging shortcircuit currents faster than any mechanical protective device.
• Excellent time-delay — Eliminates needless downtime caused by
power surges or equipment demands. Permits selection of fuse sizes
closer to actual load conditions, which provides better protection.
• 300kA Interrupting Rating — Littelfuse self-certified to 300,000
amperes as standard. Meets future trend towards higher available
short-circuit currents.

*Consult the Motor Protection Tables in the Fuseology section for specific motor sizing information

Specifications
Voltage Ratings:

Ampere Ratings

AC: 600 Volts
DC: 250 Volts (CCMR 2 ⁄10 — 2A)
(CCMR 41⁄ 2 — 10A)
(CCMR 35 — 60A)
300 Volts (CCMR 2 1⁄ 4 — 4A)
500 Volts (CCMR 12 — 30A)
Interrupting Ratings:
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
DC: 20,000 amperes
2
⁄10 — 60 amperes
Ampere Range:
Approvals:
AC: Standard 248-4, Class CC
UL Listed 2 ⁄10 – 30 amps (File No: E81895)
Standard 248, Class CD
UL Listed 35 – 60 amps (File No: E81895)
CSA Certified 2 ⁄10 – 60 amps
(File No: LR29862)
DC: Littelfuse self-certified

20

2

⁄10
⁄4
3
⁄10
1
⁄2
6
⁄10
8
⁄10
1

1
11⁄4
14 ⁄10
11⁄2
16 ⁄10
1 8 ⁄10

2
2 1⁄4
2 1⁄ 2
2 8 ⁄10
3
3 2 ⁄10

3 1⁄2
4
4 1⁄2
5
5 6 ⁄10
6

61⁄4
7
7 1⁄2
8
9
10

12
15
17 1⁄ 2
20
25
30

35
40
45
50
60

Example part number (series & amperage): CCMR 40

Recommended Fuse Blocks
LPSC (CCMR 2 ⁄10 — 30A)
L60030C series (CCMR 2 ⁄10 — 30A)
L60060C series (CCMR 35 — 60A)
Refer to Blocks & Holders section of this catalog for additional information.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

CCMR Series POWR-PRO® Class CC and CD Fuses
600 VAC • Dual-Element, Time-Delay • 2/10 – 60 Amperes
.25"
(6.4 mm)

1.50"

.41"

0-30A

.850"

(10.3 mm)

POWR-PRO® Fuses

(38.1 mm)

35-60A

(21.6 mm)

.125"
(3.2 mm)

.50"
(12.7 mm)

1.880"
(47.8 mm)

Current-Limiting Effects of CCMR (600V) fuses
Apparent RMS Symmetrical For Various Fuse Ratings

Short Circuit Current*
2A
160
180
200
220
230
240
245
255
260
280
300
310
340
350

5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
80,000
100,000
150,000
200,000

6 1⁄ 4 A
330
400
430
460
480
500
520
550
570
600
625
650
700
750

4A
190
220
250
260
280
290
300
310
330
340
360
380
420
440

10A
370
440
480
520
550
570
590
600
640
670
700
750
800
850

12A
525
600
675
720
750
800
825
850
875
900
1,000
1,050
1,150
1,200

15A
600
700
775
825
850
900
925
975
1,000
1,050
1,125
1,200
1,300
1,400

20A
625
725
800
850
900
950
975
1,000
1,100
1,125
1,200
1,250
1,400
1,450

30A
750
875
950
1,000
1,050
1,125
1,175
1,200
1,300
1,350
1,400
1,500
1,600
1,750

1000000
800000
600000

60A

8/10A
1A
1 1/4A
1 1/2A
1 8/10A
2A
2 1/2A
3A
3 1/2A
4A
6A
8A
10A
12A
15A
20A
25A
30A
35A

1/2A

1/4A

*Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves

1000
800
600

400000
300000

400
300

200000

100
80
60

100000
80000
60000

40
30

40000
30000

20

20000

10
8
6

10000
8000
6000

4
3

2000

1
.8
.6

4A
2A

1000
800
600

.4
.3
.2

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

600
800
1000

300
400

200

60
80
100

30
40

20

6
8
10

3
4

2

.6
.8
1

.3
.4

.2

.08
.1

2000

100

.02

600
800
1000

.04
.03

100

200

300
400

400
300

.1
.08
.06

.05

30A
20A
15A
12A
10A
6 1/4A

4000
3000

2

.01

60A

200

TIME IN SECONDS

200

CURRENT IN AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

21

POWR-PRO® Fuses

IDSR Series Indicator® POWR-PRO® Class RK5 Fuse
600 V AC/DC • Time-Delay • 1/10 – 600 Amperes

POWR-PRO® Fuses

Money is wasted each time a circuit opens and halts production.
The indicator window of the IDSR allows maintenance personnel to
pinpoint blown fuses immediately. The circuit can then be tested and
any problem corrected without unnecessary delay, minimizing costly
downtime.

Applications
DC circuits
All general purpose circuits
Motors
Transformers
Solenoids
Fluorescent lighting
All system components with high in-rush currents

Features/Benefits

The Littelfuse IDSR Indicator fuse offers a patented solid-state design
and provides state-of-the-art reliability along with the convenience of
blown fuse indication. The unique design of the IDSR also features a
600 volt AC/DC rating making it ideal for DC applications.

• Superior Performance – Littelfuse leading edge metallurgy
eliminates all moving parts in a true dual-element design. The IDSR
also provides superior time-delay to withstand minor current surges
without sacrificing protection for sustained overloads or shortcircuit conditions.
• 600 Volt AC/DC Rating – The IDSR is UL Listed for 600 volts
AC/DC, which makes it ideal for a variety of applications. It is also
MSHA approved.
• Reduce Downtime – Costly downtime is minimized using Littelfuse
Indicator fuses. A glance at the indicator window tells if the fuse
has blown. If the window is dark, the fuse has opened. It’s that
simple.
• Increase Safety – Littelfuse Indicator Fuses minimize exposure to
“live” circuit parts while searching for a blown fuse. Other forms of
indication require current to power a light. Littelfuse Indicator fuses
can be identified with the power off.

Specifications

Ampere Ratings

Voltage Ratings:
Interrupting Ratings:

Ampere Range:
Approvals:

22

AC: 600 Volts
DC: 600 Volts
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
DC: 20,000 amperes
1
⁄10 – 600 amperes
Standard 248-12 and UL 198M, Class RK5
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
MSHA 600 Volt Listing

1

⁄10
⁄8
15
⁄100
2
⁄10
1
⁄4
3
⁄10
4
⁄10
1
⁄2
1

6

⁄10
⁄10
1
11⁄8
11⁄4
14 ⁄10
1 1⁄2
16 ⁄10
8

18 ⁄10
2
2 1⁄ 4
2 1⁄ 2
2 8 ⁄10
3
3 2 ⁄10
3 1⁄2

4
4 1⁄2
5
5 6 ⁄10
6
6 1⁄ 4
7
7 1⁄ 2

8
9
10
12
15
17 1⁄ 2
20
25

30
35
40
45
50
60
70
75

80
90
100
110
125
150
175
200

225
250
300
350
400
450
500
600

Example part number (series & amperage): IDSR 30
Note: All fuses rated 1 amp and above are Indicator ® fuses.

Dimensions

Recommended Fuse Blocks

Please refer to the FLSR_ID dimensions.

LR600 series
Refer to the Blocks & Holders section of this catalog for additional information.
Contact Littelfuse for characteristic curves.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

POWR-PRO® Fuses

LDC Series POWR-PRO® Class L Fuses
600 V AC/DC Time-Delay • 150 – 2000 Amperes

POWR-PRO® Fuses

constants. This makes the fuse uniquely suited for applications such
as crane rail circuits and mass transit systems. Contact the factory for
application information.
For AC only systems, consider the use of POWR-PRO KLPC series
fuses. They have a full 10 seconds time-delay at 500% rated current,
and have a wider range of ratings.

Applications
UPS protection, especially for large battery circuits
DC distribution
DC variable speed drives
Protection of crane rail circuits and other large DC equipment such as
electrical power shovels, ship and dock cranes, etc.
Mass transit systems, including new light rail applications
General purpose AC/DC circuits for mains, feeders, and branch circuits

Features/Benefits

While LDC series fuses UL Listed DC interrupting rating is more than
adequate for most applications (50,000 amperes at a 16 millisecond
time constant), tests in our high power laboratory have shown that
this remarkable fuse is capable of performing at much longer time

• 600 Volt AC/DC rated — “All-purpose” Class L fuses reduce
inventory requirements because the need for separate AC and DC
fuses is eliminated.
• UL Listed 200,000 A.I.R. AC – 50,000 A.I.R. DC — Reliable
interruption of all overcurrents up to their ratings. Minimizes the need
for time consuming and expensive short-circuit studies.
• Moderate time-delay — Four seconds time-delay at 500% current
provides adequate time-delay for many AC applications and most
DC applications. They will withstand most harmless overloads or line
surges. If your needs exceed the LDC capabilities, consider the use
of KLPC fuses for AC applications.
• Selective coordination — LDC series fuses coordinate well with all
Littelfuse fuses rated 600 amperes or less. A combination of LDC
and IDSR series fuses provide a complete 600 volt rated DC system.
• Extremely current-limiting — Maximum current limitation reduces
damage to circuits and equipment under short-circuit conditions.
Stops damaging short-circuits faster than any mechanical protective
device.

Specifications

Ampere Ratings

Littelfuse POWR-PRO LDC series Class L fuses represent another
first in fuse protection. LDC series fuses are the first UL Listed 600
volts AC and DC Class L fuses. Since they may be used for both
AC and DC, they eliminate the concern that AC only fuses may be
inserted into DC circuits.

Voltage Ratings:
Interrupting Ratings:

Ampere Range:
Approvals:

AC:
DC:
AC:
DC:

600 Volts
600 Volts
200,000 amperes rms symmetrical
50,000 amperes
(16 millisecond time-constant)
150 – 2000 amperes
Standard 248-10, Class L
UL Listed 601 – 2000 amps (File No: E81895)
UL Recognized 150 – 600 amps
(File No: E71611)
CSA Certified 150 – 2000 amps
(File No: LR29862)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

150
200
250
300
350
400

450
500
600
601
650
700

750
800
900
1000
1100
1200

1300
1350
1400
1500
1600
1800

1900
2000

Example part number (series & amperage): LDC 1200

Dimensions
Please refer to the KLPC dimensions

www.littelfuse.com

23

POWR-PRO® Fuses

LDC Series POWR-PRO® Class L Fuses
600 V AC/DC Time-Delay • 150 – 2000 Amperes

POWR-PRO® Fuses

Current-Limiting Effects of LDC (600V) Fuses
Apparent RMS Symmetrical for Various Fuse Ratings

Short-Circuit Current*

800A
5,000
8,500
9,750
10,500
11,500
12,000
12,500
13,500
14,000
15,000
16,000
18,000
20,000
23,000

5,000
10,000
15,000
20,000
25,000
30,000
35,000
40,000
50,000
60,000
80,000
100,000
150,000
200,000

1200A
5,000
10,000
14,000
15,000
16,000
17,000
18,000
19,000
21,000
22,000
24,000
25,000
30,000
32,000

1600A
5,000
10,000
15,000
19,000
21,000
22,000
23,000
24,000
26,000
28,000
30,000
33,000
38,000
41,000

2000A
5,000
10,000
15,000
20,000
25,000
26,000
28,000
30,000
32,000
34,000
36,000
40,000
44,000
46,000

800A
1200A
1600A
2000A

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves

1000
800
600

1000000
800000
600000

400
300

400000
300000

200

200000
100
80
60

PEAK LET-THRU IN AMPERES

20
10
8
6
4
3
2
1
.8
.6
.4
.3

40000
30000
20000
10000
8000
6000
4000
3000
2000

.2

1000
800
600

.1
.08
.06

400
300
200

.04
.03

CURRENT IN AMPERES

24

www.littelfuse.com

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

100
600000
800000
1000000

200000

300000
400000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

300
400

600
800
1000

200

100

.01

300
400

100

.02

200

TIME IN SECONDS

2000A
1600A
1200A
800A

100000
80000
60000

40
30

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

© 2005 Littelfuse • POWR-GARD™ Products Catalog

KLLU Class L Fuses

26-28

FLNR_ID/FLSR_ID Indicator® Class RK5 Fuses

29-32

FLNR/FLSR Class RK5 Fuses

33

KLNR/KLSR Class RK1 Fuses

34-35

NLN/NLS Class K5 Fuses

36-37

RLN/RLS Class H Fuses

38

JLS Class J Fuses

39-40

JLLN/JLLS POWR-T ™ Class T Fuses

41-43

SLC Class G Fuses

44

Class CC and Class CD Fuses

45-47

Plug Fuses

48

www.littelfuse.com

General Purpose Fuses

KLLU Class L Fuses
600 VAC • Time-Delay • 601 – 4000 Amperes

Applications

General Purpose Fuses

Service switches
Switchboard mains and feeders
Bolted pressure contact switches
Motor control center mains
Large motor branch circuits
UL Listed series rated protection for molded case circuit breaker
panelboards and loadcenters. See panelboard manufacturers’
literature for recommended fuse rating.

Safety
• 200,000 A.I.R. — Provides reliable interruption of all overcurrents up
to 200,000 amperes.
• When used for motor branch circuit protection, KLLU fuses may be
sized close to the motor full load current, providing excellent protection
to branch circuit conductors, motor control equipment and motors.

Longer Equipment Life

KLLU series UL Listed, time-delay, Class L fuses are quality fuses,
developed to provide a somewhat lower priced alternate to the
POWR-PRO ® KLPC series fuses. KLLU series fuses meet or exceed
all UL requirements for Class L fuses. For superior protection and
performance, specification-grade POWR-PRO KLPC series fuses are
the recommended fuse. Complete information on KLPC fuses may
be found in the POWR-PRO Fuse section of this catalog.

• Current-Limiting — Reduces short-circuit damage to systems and
equipment.
• Reduced downtime.
• Ten second minimum time-delay at 500% current eliminates
needless downtime caused by heavy starting currents of large
motors and other inductive loads.
• Selective coordination — KLLU fuses coordinate well with other
Class L fuses and with all current-limiting Littelfuse fuses rated 600
amps or less. This means less time spent trying to locate shortcircuits or overloaded equipment, because only the fuse immediately
on the line side of the affected circuit opens.

Easy To Use
• 200,000 A.I.R. rating minimizes need for short-circuit calculations,
while meeting present and future system requirements.
• KLLU fuse time-current characteristics closely match typical timecurrent curves of circuit breakers. Although fuse/circuit breaker systems
can seldom be 100% coordinated, KLLU series fuses permit use of a
wider range of breaker setting than fast acting Class L fuses.
Excellent protection for a single breaker or a group of breakers.

Specifications
Voltage Ratings:
Interrupting Ratings:
Ampere Range:
Approvals:

26

Ampere Ratings
AC: 600 Volts
DC: Contact factory
200,000 amperes rms symmetrical
601 – 4000 amperes
Standard 248-10, Class L
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)

601
650
700

750
800
900

1000
1200
1350

1400
1500
1600

1800
2000
2500

3000
3500
4000

Example part number (series & amperage): KLLU 1000

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

KLLU Class L Fuses
600 VAC • Time-Delay • 601 – 4000 Amperes

J
J
H

J

D E F

C B A

M

C B A

D E F

N
M

N
M

G

FIG.2

FIG.1

General Purpose Fuses

F

C B A

FIG. 3

J
H

C B A

D E F
L
K

N
M

G

FIG. 4

Dimensions In Inches (mm in parentheses)

Fig.
No.

A

B

C

1

3 3 ⁄4
(95.3)

53 ⁄4
(146.1)

63 ⁄4
(171.5)

801 – 1200

2

33 ⁄4
(95.3)

53 ⁄4
(146.1)

1201 – 1600

2

33 ⁄4
(95.3)

1601 – 2000

2

2001 – 2500

Amperes

E

F

—

—

8 5 ⁄8
(219.1)

63 ⁄4
(171.5)

91⁄ 4
(235.0)

91⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

53 ⁄4
(146.1)

63 ⁄4
(171.5)

91⁄ 4
(235.0)

9 1⁄ 2
(241.3)

33 ⁄4
(95.3)

53 ⁄4
(146.1)

63 ⁄4
(171.5)

91⁄ 4
(235.0)

3

4

53 ⁄4
(146.1)

6 3 ⁄4
(171.5)

2501 – 3000

3

4

53 ⁄4
(146.1)

6 3 ⁄4
(171.5)

3001 – 4000

4

4

601 – 800

D

H

J

K

—

2
(50.8)

2 1⁄ 2
(63.5)

—

—

2
(50.8)

2 1⁄ 2
(63.5)

(9.5)

10 3 ⁄ 4
(273.1)

—

—

2 3 ⁄8
(60.3)

3
(76.2)

(11.1)

9 1⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

—

—

23 ⁄4
(69.9)

31⁄ 2
(88.9)

(12.7)

91⁄ 4
(235.0)

9 1⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

15 ⁄ 8
(41.3)

13 ⁄ 4
(44.5)

31⁄ 2
(88.9)

5
(127.0)

(19.1)

91⁄ 4
(235.0)

9 1⁄ 2
(241.3)

10 3 ⁄ 4
(273.1)

15 ⁄ 8
(41.3)

13 ⁄ 4
(44.5)

4
(101.6)

5
(127.0)

103 ⁄4
(273.1)

13 ⁄4
(44.5)

3 1⁄ 4
(82.6)

43 ⁄4
(120.7)

53 ⁄4
(146.1)

53 ⁄4

63 ⁄4

91⁄ 4

91⁄2

(146.1)

(171.5)

(235.0)

(241.3)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

G
—

www.littelfuse.com

L
3

⁄8

(9.5)
3

5

M

N

⁄8 x 11 ⁄8

—

(15.9) x (28.6)
5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄8 x 11 ⁄ 8
(15.9) x (28.6)

5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄8 x 11 ⁄ 8
(15.9) x (28.6)

5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄8 x 11 ⁄ 8
(15.9) x (28.6)

5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄8 x 11 ⁄ 8
(15.9) x (28.6)

(19.1)

5
⁄8 x 3 ⁄4
(15.9) x (19.1)

5
⁄ 8 x 11 ⁄ 8
(15.9) x (28.6)

3
⁄4
(19.1)

5
⁄8 x 13 ⁄8
(15.9) x (34.9)

5
⁄8 x 13 ⁄ 8
(15.9) x (34.9)

7

⁄8

⁄16

1

⁄2

3

3

⁄4
⁄4

27

General Purpose Fuses

KLLU Class L Fuses
600 VAC • Time-Delay • 601 – 4000 Amperes
Current-Limiting Effects of KLLU (600V) fuses
Apparent RMS Symmetrical Current for Various Fuse Ratings

General Purpose Fuses

Short-Circuit Current*
800A

1200A

1600A

2000A

3000A

4000A

5,000

5,000

5,000

5,000

5,000

5,000

5,000

10,000

10,000

10,000

10,000

10,000

10,000

10,000

15,000

11,900

15,000

15,000

15,000

15,000

15,000

20,000

13,000

18,500

20,000

20,000

20,000

20,000

25,000

14,000

20,000

25,000

25,000

25,000

25,000

30,000

14,500

21,000

26,500

30,000

30,000

30,000

35,000

15,000

22,000

28,500

34,000

35,000

35,000

40,000

16,000

23,000

30,000

35,000

37,000

40,000
44,000

50,000

17,000

24,000

32,000

38,000

39,000

60,000

18,000

26,000

34,000

42,000

43,000

50,000

80,000

19,000

28,000

36,000

44,000

46,000

54,500

100,000

21,000

30,000

38,000

46,000

48,000

57,500

150,000

24,000

35,000

44,000

50,000

51,000

68,000

200,000

26,000

38,000

48,000

53,000

60,000

74,000

601A
800A
1200A
1600A
2000A
3000A
3500A
4000A

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves

10000000

1000
800
600
400
300
200
100
80
60

1000000
PEAK LET-THRU IN AMPERES

40
30

TIME IN SECONDS

20
10
8
6
4
3
2
1
.8
.6
.4
.3

4000A
3000A
2000A
1600A
1200A
800A

100000

10000

.2
.1
.08
.06

CURRENT IN AMPERES

28

www.littelfuse.com

200000

100000

100

600000
800000
1000000

300000
400000

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

200

50

1000
80
100

.01

10000

.02

1000

.04
.03

AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

FLNR_ID/FLSR_ID Indicator® Class RK5 Fuses
250/600 VAC • Dual-Element, Time Delay • 1/10 – 600 Amperes

Applications

General Purpose Fuses

Service entrance switches
Switchboard main and feeder switches
Motor control center mains and motor branch circuits
Individual fused combination motor controllers
Distribution panelboards
Industrial control panels
Protection of fully rated panelboards and loadcenters
All general purpose circuits

Features/Benefits

Littelfuse FLNR_ID/FLSR_ID Indicator fuses provide blown fuse
indication at a glance. The patented state-of-the-art solid state design
provides maximum reliability and superior performance characteristics
in a true dual-element design. The use of Indicator fuses reduces
downtime and nuisance openings, increases safety, and can save
thousands of dollars in lost production time.

Specifications
Voltage Ratings:

Interrupting Ratings:

Ampere Range:
Approvals:

• Reduce Downtime — A glance at the indicating window of a FLNR_ID
or FLSR_ID Indicator fuse pinpoints open fuses. If the indicating strip
is black, the fuse has opened. It’s that simple.
• Reduce Nuisance Opening — FLNR_ID and FLSR_ID Indicator
fuses have superior time-delay and cycling characteristics which can
lengthen fuse life and decrease needless opening.
• Reduce Fuse Inventory — Because FLNR_ID and FLSR_ID Indicator
fuses have superior performance characteristics, they can be used on a
variety of applications, thus decreasing fuse inventory.
• Reduce Equipment Damage — FLNR_ID and FLSR_ID Indicator
fuses have superior overload and short-circuit protection which can
reduce equipment damage.
• Reduce Accidents — The FLNR_ID and FLSR_ID Indicator fuses
improve safety by minimizing exposure to live circuits. Unlike other
forms of blown fuse indication, it doesn’t matter if the power is on
or off. No second guessing whether a light means a fuse is good or
bad, and no current going across a blown fuse to power a lighted
accessory.

Ampere Ratings
AC: 250 Volts (FLNR_ID);
600 Volts (FLSR_ID)
DC: 125 Volts (FLNR 1⁄10 – 30A);
125 Volts (FLNR_ID 35 – 600A);
300 Volts (FLSR_ID)
AC: 200,000 amperes rms symmetrical
300,000 amperes rms symmetrical
(Littelfuse self-certified)
DC: 20,000 amperes
1
⁄10 – 600 amperes
Standard 248-12, Class RK5
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
MSHA 300 Volt Listing (FLSR_ID)
QPL: Federal Specification WF-1814

6
⁄10**
⁄10
18 ⁄10
4
8
30
80
225
8
1
⁄8
⁄10
2
41⁄2
9
35
90
250
15
⁄100
1
2 1⁄4
5
10
40
100
300
2
⁄10
11⁄ 8
2 1⁄2
5 6 ⁄10
12
45
110
350
1
⁄4
11⁄4
2 8 ⁄10
6
15
50
125
400
3
⁄10
14 ⁄10
3
6 1⁄4
171⁄ 2
60
150
450
4
⁄10
11⁄ 2
3 2 ⁄10
7
20
70
175
500
1
⁄2
16 ⁄10
31⁄2
71⁄ 2
25
75*
200
600
*FLSR_ID only **FLNR only
Example part number (series & amperage): FLSR100ID
NOTE: For 1⁄10 – 30 ampere 250 volt fuses, order non-indicating FLNR series fuses.
NOTE: All FLNR_ID fuses rated 35 – 600A are Indicator fuses.
NOTE: All FLSR_ID fuses rated 1 amp and above are Indicator fuses.
1

Recommended Fuse Blocks
LR250 series (for FLNR_ID series fuses)
LR600 series (for FLSR_ID series fuses)
Refer to Blocks & Holders section of this catalog for additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

29

General Purpose Fuses

FLNR_ID/FLSR_ID Indicator® Class RK5 Fuses
250/600 VAC • Dual-Element, Time Delay • 1/10 – 600 Amperes
A

A

F

K

G

B

D

F

B

General Purpose Fuses

1

/10 – 30

1

35 – 60

1

70 – 100

2

110 – 200

2

225 – 400

2

450 – 600

2

G

J

C

70-600A

FIG. 1
Refer To
Fig. No.

D

H

E

Amperes

E

C

FIG. 2
Dimensions In Inches (mm in parentheses)

Series

A

B

C

D

FLNR

2 (50.8)

12

12

9 16

FLSR_ID

5 (127.0)

3 4

5 8

13 16

FLNR_ID

3 (76.2)

3 4

⁄ (19.1)

5 8

13 16

FLSR_ID

51⁄2 (139.7)

1 (25.4)

5 8

⁄ (15.9)

11 ⁄16 (27.0)

FLNR_ID

5 7⁄8 (149.2)

1 (25.4)

11 ⁄16 (27.0)

11 ⁄16 (27.0)

78

⁄ (12.7)

⁄ (12.7)

⁄ (19.1)

1 4

⁄ (15.9)
⁄ (15.9)

1 16

⁄

⁄ (20.6)
⁄ (20.6)

5 16

FLSR_ID

7 ⁄ (200.0)

1 ⁄ (31.8)

FLNR_ID

71⁄8 (181.0)

11⁄2 (38.1) 115 ⁄ 32 (37.3) 119 ⁄32 (40.5)

FLSR_ID

9 5 ⁄8 (244.5)

13 ⁄ 4 (44.5) 115 ⁄ 32 (37.3) 127⁄ 32 (46.8)

FLNR_ID

8 5 ⁄ 8 (219.1)

FLSR_ID

115 ⁄8 (295.3) 21⁄2 (63.5)
3 8

2 (50.8)
12

3 (76.2)

1 ⁄ (27.0)

1 ⁄ (33.3)

115 ⁄ 16 (49.2) 2 3 ⁄32 (53.2)
2 (50.8)
3 8

2 19 ⁄32 (65.9)
19 32

FLNR_ID

10 ⁄ (263.5) 2 ⁄ (63.5)

2 ⁄ (60.3)

2 ⁄

FLSR_ID

13 3 ⁄8 (339.7)

2 13 ⁄ 32 (61.1) 3 3 ⁄32 (78.6)

E
(2.0)
3 32
⁄ (2.4)
3 32
⁄ (2.4)
3 32
⁄ (2.4)
18
⁄ (3.2)
18
⁄ (3.2)
3 16
⁄ (4.8)
3 16
⁄ (4.8)
14
⁄ (6.4)
14
⁄ (6.4)
14
⁄ (6.4)
14
⁄ (6.4)

5 64

⁄ (14.3)

(65.9)

F
(4.0)
3 16
⁄ (4.8)
3 16
⁄ (4.8)
14
⁄ (6.4)
3 4
⁄ (19.1)
3 4
⁄ (19.1)
11⁄ 8 (28.6)
11⁄ 8 (28.6)
15 ⁄8 (41.3)
15 ⁄8 (41.3)
2 (50.8)
2 (50.8)
5 32

G

H

J

K

⁄ (9.5)

—

—

—

5 8

—

—

—

5 8

—

—

—

78

—

—

—

3 8

⁄

⁄ (15.9)
⁄ (15.9)

⁄ (22.2)

11⁄4 (31.8)

14

9 32

⁄

(7.1)

12

1 ⁄ (38.1)

14

9 32

⁄

(7.1)

12

127⁄32 (46.8)

7 16

9 32

⁄

(7.1)

11 16

23 ⁄32 (53.2)

7 16

9 32

⁄

(7.1)

11 16

211 ⁄ 32 (59.5)

5 8

13 32

⁄

(10.3)

15 16

2 27⁄ 32 (72.2)

5 8

13 32

⁄

(10.3)

15 16

(72.2)

3 4

17 32

⁄

(13.5)

11⁄ 8 (28.6)

311⁄32 (84.9)

3 4

17 32

(13.5)

11⁄ 8 (28.6)

12

27 32

2 ⁄

⁄ (6.4)
⁄ (6.4)

⁄ (11.1)
⁄ (11.1)
⁄ (15.9)
⁄ (15.9)
⁄ (19.1)
⁄ (19.1)

⁄

⁄ (12.7)
⁄ (12.7)
⁄ (17.5)
⁄ (17.5)

⁄ (23.8)
⁄ (23.8)

2/10A
1/4A
3/10A
4/10A
1/2A
6/10A
8/10A
1A
1 1/4A
1 4/10A
2A
2 1/2A
4 1/2A
5A
7A
7 1/2A
9A

FLSR_ID

1000
800
600

1000
800
600
400
300
200

400
300
200
100
80
60

100
80
60
40
30
20

40
30
20
10
8
6

TIME IN SECONDS

TIME IN SECONDS

1A
1.25A
1.6A
2A
2.5A
3A
4A
6A

FLNR

4
3
2
1
.8
.6

10
8
6
4
3
2

.4
.3

1
.8
.6
.4
.3

.2

.2

.1
.08
.06

.1
.08
.06
.04
.03
.02

.04
.03
.02

.01
600
800
1000

200

60
80
100

30
40

20

6
8
10

2

3
4

.6
.8
1

.3
.4

.1

.2

300
400

CURRENT IN AMPERES

CURRENT IN AMPERES

www.littelfuse.com

10000
8000
6000
4000
3000
2000

1000
800
600
400
300
200

100
80
60
40
30
20

10
8
6
4
3
2

1

.01

30

10A
15A
20A
25A
30A

For additional application information request Product Bulletin EL-4

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

FLNR_ID/FLSR_ID Indicator® Class RK5 Fuses
250/600 VAC • Dual-Element, Time Delay • 1/10 – 600 Amperes
Current-Limiting Effects of FLNR_ID (250V) fuses
Short-Circuit Current*

Apparent RMS Symmetrical Current for Various Fuse Ratings
60A

100A

200A

400A

600A

1,400

2,100

3,100

5,000

5,000

5,000

10,000

1,550

2,500

3,900

6,500

9,500

10,000

15,000

2,000

3,150

4,400

7,250

10,500

14,000

5,000

20,000

2,250

3,400

5,000

8,250

12,000

16,000

25,000

2,400

3,750

5,250

9,000

12,500

16,500

30,000

2,550

4,100

5,600

9,500

13,500

18,000

35,000

2,650

4,300

5,800

9,750

14,000

19,000

40,000

2,800

4,400

6,250

10,250

15,000

20,000

50,000

3,000

5,000

6,500

10,500

16,000

21,000

60,000

3,200

5,250

7,000

11,500

17,000

23,000

80,000

3,400

5,750

7,500

12,500

19,000

25,500

100,000

3,850

6,000

8,000

13,500

21,000

27,500

150,000

4,100

7,000

9,000

15,200

24,000

31,500

200,000

4,300

7,500

9,750

16,500

26,000

34,000

General Purpose Fuses

30A

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves

Current-Limiting Effects of FLSR_ID (600V) fuses
Short-Circuit Current*
5,000

Apparent RMS Symmetrical Current for Various Fuse Ratings
30A

60A

100A

200A

400A

600A

1,250

2,100

3,200

5,000

5,000

5,000

10,000

1,600

2,850

4,300

7,250

10,000

10,000

15,000

1,800

3,400

5,000

8,500

13,500

15,000
19,000

20,000

2,250

3,800

5,500

9,500

15,750

25,000

2,450

4,100

5,700

10,250

17,000

21,000

30,000

2,700

4,500

6,400

10,750

18,000

23,000

35,000

2,900

4,800

6,700

11,500

19,000

24,250

40,000

3,000

5,000

7,250

12,000

19,500

27,000

50,000

3,400

5,250

7,750

13,000

21,000

29,000

60,000

3,600

5,750

8,100

14,000

22,000

30,500

80,000

3,900

6,250

9,000

15,000

24,000

33,000

100,000

4,300

6,750

9,750

16,500

26,000

35,000

150,000

4,500

7,600

11,100

19,000

28,000

38,000

200,000

4,600

8,400

12,250

21,500

30,000

40,000

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

31

General Purpose Fuses

FLNR_ID/FLSR_ID Indicator® Class RK5 Fuses
250/600 VAC • Dual-Element, Time Delay • 1/10 – 600 Amperes

FLNR_ID
100A

FLSR_ID

400A 600A

200A

1000
800

600

600

400

400

300

300

200

200

100
80

100
80

60

60

40

40

30

30

20

20

TIME IN SECONDS

TIME IN SECONDS

General Purpose Fuses

60A
1000
800

10
8
6
4
3
2

1
.8

60A

100A

200A

400A 600A

10
8
6
4
3
2

1
.8

100000
80000

60000

40000

30000

20000

10000
8000

6000

4000

3000

2000

1000
800

600

400

300

200

100
80

60

40

30

20

10
8

6
5

1000000
800000

600000

400000

300000

200000

100000
80000

60000

40000

30000

20000

.01

10000
8000

.02

.01

6000

.03

.02

4000

.03

3000

.06
.05
.04

2000

.04

1000
800

.1
.08

.06

600

.1
.08

400

.2

300

.3

.2

200

.4

.3

100
80

.6

.4

60
50

.6

CURRENT IN AMPERES

30A

15A

CURRENT IN AMPERES

FLSR_ID

FLNR_ID

1000000

1000000

800000

800000

600000

600000
400000

400000

300000

300000
200000

200000
100000

80000

600A

60000

400A
200A

40000
30000

100A
20000
60A
10000
8000
6000
4000
3000

PEAK LET - THRU IN AMPERES

PEAK LET - THRU IN AMPERES

600A

80000

100000

400A

60000
50000

200A

40000
30000

100A

20000

60A

10000

30A

8000
6000
5000

15A

4000
3000
2000

2000
1000

1000

800

800

600

600
400

400

300

300
200

200

200000

100000

80000

60000

40000

30000

20000

10000

8000

6000

4000

3000

2000

1000

800

www.littelfuse.com

600

32

300

200

100

200000

100000

80000

60000

40000

30000

20000

10000

8000

6000

4000

3000

2000

1000

800

600

300

400

200

100

AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

400

100

100

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

FLNR/FLSR Class RK5 Fuses
250/600 VAC • Dual-Element, Time-Delay • 1/10 – 600 Amperes

Applications

General Purpose Fuses

Service entrance switches
Switchboard main and feeder switches
Motor control center mains and motor branch circuits
Individual fused combination motor controllers
Distribution panelboards
Industrial control panels
Protection of fully rated panelboards and loadcenters
All general purpose circuits

Safety
• 200,000 A.I.R. — Reliable interruption of all overcurrents up to
200,000 amperes.
• Faster acting short-circuit protection than any non-current-limiting
mechanical protective device.

Reliability
• Accurate and reliable — Automated, precision manufactured and
assembled parts ensure accurate, consistent response to overloads
and short-circuits.

Longer Equipment Life

Littelfuse FLNR/FLSR series fuses have been the superior UL Class
RK5 dual-element time-delay fuses, and are the most widely used class
of fuses. FLNR/FLSR series fuses provide excellent protection for all
types of circuits especially those containing motors. However, users and
specifiers should consider the significant benefits offered by Indicator
fuses. Complete information on these fuses may be found earlier in this
section.

Specifications
Voltage Ratings:

Interrupting Ratings:
Ampere Range:
Approvals:

• Reduced damage to equipment caused by heating and magnetic
forces of short-circuits.
• Equipment runs cooler with low-resistance dual-element fuses.

Ampere Ratings
AC: 250 Volts (FLNR)
600 Volts (FLSR)
DC: 125 Volts (FLNR)
300 Volts (FLSR)
AC: 200,000 amperes rms symmetrical
DC: 20,000 amperes
1
⁄10 – 600 amperes
Standard 248-12, Class RK5
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
MSHA 300 Volt Listing (FLSR)
QPL: Federal Specification WF-1814

Dimensions
Refer to FLNR_ID series for FLNR dimensions and FLSR_ID series for FLSR
dimensions.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

6
⁄10
⁄10
18 ⁄10
4
8
8
⁄8
⁄10
2
4 1⁄2
9
15
⁄100
1
2 1⁄ 4
5
10
2
⁄10
11⁄ 8
2 1⁄2
5 6 ⁄10
12
1
⁄4
11⁄ 4
2 8 ⁄10
6
15
3 **
⁄10
14 ⁄10
3
6 1⁄ 4
17 1⁄ 2
4
⁄10
11⁄2
3 2 ⁄10
7
20
1
⁄2
16 ⁄10
3 1⁄2
71⁄ 2
25
**FLNR only,
Example part number (series & amperage): FLSR100
1

1

30
35
40
45
50
60
70
75

80
90
100
110
125
150
175
200

225
250
300
350
400
450
500
600

Recommended Fuse Blocks
LR250 series (for FLNR series fuses)
LR600 series (for FLSR series fuses)
Refer to Blocks & Holders section of this catalog for additional information.

www.littelfuse.com

33

General Purpose Fuses

KLNR/KLSR Class RK1 Fuses
250/600 VAC • Fast Acting • 1 – 600 Amperes

Applications

General Purpose Fuses

Resistance heaters
Lighting circuits
Non-inductive loads
Molded case circuit breaker load centers and panelboards have
increased interrupting ratings when series rated with Littelfuse
KLNR/KLSR Class RK1 fuses. Refer to panelboard manufacturer’s
literature for UL Listed combination of fuses and panelboards. Series
ratings up to 200,000 amperes are available.

Safety
• 200,000 A.I.R. — Reliable interruption of all overcurrents up to
200,000 amperes.
• Extremely current-limiting — Stops damaging short-circuit current
faster than any mechanical protective device.
• Fast-acting — Provides fast acting protection to equipment such
as variable speed drives, rectifiers and other equipment containing
surge-sensitive components.

Longer Equipment Life
• Current-limiting design reduces damage to equipment caused by
heating and magnetic effects of short-circuit currents.

Economical
KLNR/KLSR series RK1 fuses were the earliest type of current-limiting
fuses developed. Their single-element, silver link design enables them
to provide fast-acting overload and short-circuit protection. When used
to protect inductive loads such as motors, solenoids, and transformers,
KLNR/KLSR series fuses must be greatly oversized to prevent opening
the fuses on harmless in-rush currents. In such applications, KLNR/
KLSR series fuses may only provide short-circuit protection.

• Extremely current-limiting — often permits use of readily available,
less costly equipment.
• Used as input or output fuses for surge sensitive components such
as variable speed drives and rectifiers, fast acting KLNR/KLSR fuses
may prevent opening of expensive semiconductor fuses protecting
individual components.

Easy To Use

We recommend using POWR-PRO LLNRK/LLSRK series Class RK1,
dual-element, time-delay fuses in all new applications requiring the
current-limiting ability of UL Class RK1 fuses. POWR-PRO LLNRK/
LLSRK series fuses are also recommended in existing applications
where fast-acting RK1 or RK5 fuses have been opening on harmless
system surges such as motor starting currents.

• 200,000 A.I.R. rating minimizes need for short-circuit calculations.

Specifications

Ampere Ratings

®

Voltage Ratings:

In terrupting Ratings:
Ampere Range:
Approvals:

AC: 250 Volts (KLNR); 600 Volts (KLSR)
DC: 125 Volts (1 – 600A KLNR);
250 Volts (1 – 30A KLSR);
300 Volts (35 – 600A KLSR).
AC: 200,000 amperes rms symmetrical
DC: 20,000 amperes
1 – 600 amperes.
AC: Standard 248-12, Class RK1
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
DC: Littelfuse self-certified

Dimensions
• Refer to FLNR_ID for KLNR dimensions and FLSR_ID for KLSR
dimensions.

1
2
3
4
5
6
8

10
12
15
20
25
30
35

40
45
50
60
70
80
90

100
110
125
150
175
200
225

250
300
350
400
450
500
600

Example part number (series & amperage): KLNR 200

Recommended Fuse Blocks
LR250 series (for KLNR series fuses)
LR600 series (for KLSR series fuses)
Refer to the Blocks & Holders section of this catalog for additional information.

34

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

KLNR/KLSR Class RK1 Fuses
250/600 VAC • Fast Acting • 1 – 600 Amperes

400
300

200

200

100
80
60

100
80
60

40
30

40
30

20

20

10
8
6

10
8
6

TIME IN SECONDS

400
300

200A

400A
600A

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

200

60
80
100

30
40

60000
80000
100000

30000
40000

.01
20000

.02

.01

6000
8000
10000

.02

3000
4000

.04
.03

2000

.04
.03

600
800
1000

.1
.08
.06

300
400

.2

.1
.08
.06

200

.4
.3

.2

60
80
100

.4
.3

30
40

1
.8
.6

20

1
.8
.6

20

2

10

2

4
3

5

4
3

10

TIME IN SECONDS

1000
800
600

General Purpose Fuses

1000
800
600

60A
100A

30A

400A
600A

200A

60A

100A

KLSR
30A

KLNR

CURRENT IN AMPERES

CURRENT IN AMPERES

KLNR

KLSR

1000000
800000
600000

1000000
800000
600000

400000
300000

400000
300000

200000

200000

600A
400A

20000

200A
100A
60A

10000
8000
6000
4000
3000

30A

2000
1000
800
600

600A
400A

40000
30000

200A
20000
100A
10000
8000
6000

60A
30A

4000
3000
2000
1000
800
600

400
300

400
300

200

200

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

100
200

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

200

100

100

100

PEAK LET-THRU IN AMPERES

40000
30000

100000
80000
60000

PEAK LET-THRU IN AMPERES

100000
80000
60000

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

www.littelfuse.com

35

General Purpose Fuses

NLN/NLS Class K5 Fuses
250/600 VAC • “One-Time” • 1 – 600 Amperes

General Purpose Fuses

However, to obtain the added benefits of time-delay, current-limitation, and
higher interrupting rating, consider the use of POWR-PRO® FLNR_ID and
FLSR_ID Indicator® fuses for circuits up to 600 volts. The user gets all the
benefits of time-delay RK5 fuses plus the added benefits of an indicating
fuse that shows when it has opened. Complete information on these
fuses may be found in the POWR-PRO fuse section of this catalog. For
circuits up to 250 volts, see FLNR fuses in this section of the catalog.

Applications
General purpose residential and commercial circuits with little or no
motor load.
Resistive heating loads.

Economical
• For use in applications where lowest initial cost is the major consideration.

Safety
• 50,000 A.I.R., Class K5 — Adequate interrupting capacity for
residences and many smaller facilities.

NLN and NLS series fuses provide low cost protection for general purpose
feeder and branch circuits when available short-circuit currents are less
than 50,000 amperes. They replace all Class H fuses which have only a
10,000 ampere interrupting rating. They are suitable for use in many residential and smaller commercial and industrial applications.
NLKP series fuses are Canadian “Code” fuses specifically designed to
meet Canadian Electrical Code Type P fuse requirements for residential
use. They have a 10,000 ampere interrupting rating.

Specifications
Voltage Ratings:

Interrupting Ratings:

Ampere Range:
Approvals:

36

NOTE: NLKP series fuses have limited interrupting rating and should be
used only where available short-circuit current is known to be less than the
fuse interrupting rating. Where available fault current is unknown, where
it exceeds NLN/NLS interrupting rating, or where it may increase in the
future, 200,000 ampere interrupting rating Littelfuse POWR-PRO
FLNR_ID/FLSR_ID Indicator fuses and FLNR/FLSR series fuses provide
superior protection for all motor and general purpose circuits containing
inductive loads.

Ampere Ratings
AC: 250 Volts
600 Volts
DC: 250 Volts
400 Volts
500 Volts

(NLN, NLKP)
(NLS)
(NLN)
(NLS 35 – 60A)
(NLS 8 – 30A)
(NLS 225 – 600A)
600 Volts (NLS 1 – 7A)
(NLS 70 – 200A)
AC: 50,000 amperes rms symmetrical (NLN/NLS)
10,000 amperes (NLKP)
DC: 20,000 amperes (NLN/NLS 1 – 60A)
50,000 amperes (NLN/NLS 70 – 600A)
1– 600 amperes (NLN/NLS)
15 – 60 amperes (NLKP)
NLN/NLS: Standard 248-9, Class K5
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)**
**Excludes NLN 15-60A
NLKP:
Standard 248-6, Class H
UL Listed (File No: E81895)
CSA Certified (File No: LR29865)
Meets CSA “Type P” requirements

1
2
3
4
5
6

7
8
10
12
*15
*20

*25
*30
*35
*40
*45
*50

*60
70
80
90
100
110

125
150
175
200
225
250

300
350
400
450
500
600

* NLKP series available only in those amperages preceded by an asterisk.
Example part number (series & amperage): NLS 125

Recommended Fuse Blocks
LH250 series (for NLN and NLKP series fuses)
LH600 series (for NLS series fuses)
Refer to the Blocks & Holders section of this catalog for additional information.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

NLN/NLS Class K5 Fuses
250/600 VAC • “One-Time” • 1 – 600 Amperes
A

C

B

9 16

⁄

(14.3)

—

—

—

5 8

13 16

⁄

(20.6)

—

—

—

3 4

⁄ (19.1)

5 8

13 16

(20.6)

—

—

—

1 16

(27.0)

⁄

NLS

5 ⁄ (139.7)

1 (25.4)

⁄ (15.9)

1⁄

NLN

5 7⁄8 (149.2)

1 (25.4)

1 (25.4)

11 ⁄16 (27.0)

NLS

7 7⁄8 (200.0)

11 ⁄4 (31.8)

1 (25.4)

15 ⁄ 16 (33.3)

1 8

7 ⁄ (181.0)

1 ⁄ (38.1)

5 8

3 4

9 ⁄ (244.5)

1 ⁄ (44.5)

5 8

2 (50.8)

5 8

12

8 ⁄ (219.1)
11 ⁄ (295.3)

2 ⁄ (63.5)

3 8

12

10 ⁄ (263.5)

NLN

2 ⁄ (63.5)

3 8

400A

13 ⁄ (339.7)

3 (76.2)

9 16

1 ⁄ (34.9)

1⁄

3 8

27 32

1 ⁄ (34.9)

1 ⁄

78

3 32

1 ⁄ (47.6)

2⁄

78

19 32

1 ⁄ (47.6)

2 ⁄

14

19 32

2 ⁄ (57.2)

2 ⁄

14

3 32

2 ⁄ (57.2)

3⁄

NLS

600A

NLS

3 8

600

400

400

300

300

200

200

100
80

100
80

60

60

40

40

30

30

20

20

TIME IN SECONDS

1000
800

600

10
8
6
4
3
2

1
.8

—

⁄ (19.1)

15 ⁄ 16 (33.3)

1 8

3 4

19 ⁄16 (39.7)

(39.7)

3 16

1 8

17⁄ 8 (47.6)

(46.8)

3 16

1 8

23 ⁄ 32 (53.2)

(53.2)

14

5 8

213 ⁄32 (61.1)

(65.9)

14

5 8

1 ⁄ (41.3)

2 7⁄ 8 (73.0)

(65.9)

14

2 (50.8)

2 7⁄ 8 (73.0)

(78.6)

14

2 (50.8)

37⁄16 (87.3)

⁄ (3.2)
⁄ (3.2)

⁄
⁄

⁄ (19.1)

(4.8)

1 ⁄ (28.6)

(4.8)

1 ⁄ (28.6)

⁄ (6.4)

1 ⁄ (41.3)

⁄ (6.4)
⁄ (6.4)
⁄ (6.4)

10
8
6
4
3
2

1
.8

100000
80000

60000

40000

30000

20000

10000
8000

6000

4000

3000

2000

1000
800

600

400

300

200

100
80

60

30

40

CURRENT IN AMPERES

20

10
8

6
5

100000
80000

60000

40000

30000

20000

10000
8000

6000

4000

3000

2000

.01
1000
800

.02

.01

600

.03

.02

400

.03

300

.06
.05
.04

200

.04

100
80

.1
.08

.06

30

.1
.08

60

.2

40

.3

.2

20

.4

.3

10
8

.6

.4

6
5

.6

© 2005 Littelfuse • POWR-GARD™ Products Catalog

—

3 4

15A
20A
25A
30A

NLS

200A

12

—

1 8

600A

⁄ (15.9)

5 8

200A

⁄ (15.9)

60A

12

NLN

100A

⁄ (19.1)

⁄ (12.7)

400A

3 (76.2)

⁄ (12.7)

100A

3 4

NLS

60A

G

5 (127.0)

NLN

30A

15A
20A
25A

F

1000
800

TIME IN SECONDS

General Purpose Fuses

E

NLS

2

NLN

D

12

2

450 – 600

C

12

2

225 – 400

B

2 (50.8)

2

110 – 200

A

NLN
NLKP
NLN
NLKP

1

70 – 100

Dimensions In Inches (mm in parentheses)

Series

1

35 – 60

G

D

FIG. 2

Refer to
Fig. No.

1 – 30

F

B

FIG. 1

Amperes

E

A
D

C

CURRENT IN AMPERES

www.littelfuse.com

37

General Purpose Fuses

RLN/RLS Class H Fuses
250/600 VAC • Renewable • 1 – 600 Amperes
and increasing automation, which makes downtime very expensive,
have greatly reduced or eliminated the cost savings attributed to
renewable fuses.

General Purpose Fuses

We recommend the use of POWR-PRO® FLSR_ID series Indicator®
fuses for circuits between 250 and 600 volts and FLNR_ID series for
circuits 250 volts and below. Complete information on POWR-PRO
Indicator fuses may be found in the POWR-PRO fuse section of this
catalog. FLNR fuses are in this section of the catalog.

Cost Considerations
• When comparing the cost of using renewable fuses with the cost of
other fuses, the labor required for replacing links and the cost of additional downtime should be included.

Cautions
• Renewable fuses should only be used where short-circuit currents
are known to be less than 10,000 amperes, and where correct
replacement of open links is assured.
• After disassembly of fuse, examine carefully. Discard any fuses
which show evidence of weakened tube or damaged components.
• Remove all link residue from fuse tube.
• Carefully clean all contact surfaces, and remove metal spatter from
all surfaces.
• Install the proper rated fuse link and tighten all connections
securely.
• Visually examine fuses for correct alignment of blades.
Littelfuse RLN/RLS series renewable fuses are a quality product that
have traditionally been used to provide low cost protection of general
purpose feeder and branch circuits where available short-circuit currents
do not exceed 10,000 amperes. However, increased levels of available
fault current and the possibility that renewable fuses may be improperly
renewed is a potential safety hazard. In addition, escalating labor costs

Specifications
Voltage Ratings:
In terrupting Ratings:
Ampere Range:
Approvals:

FUSE LINKS:

Dimensions
• For dimensions, please refer to NLN series for RLN dimensions and
NLS series for RLS dimensions.

Ampere Ratings
AC: 250 Volts (RLN); 600 Volts (RLS)
AC: 10,000 amperes rms symmetrical
1 – 600 amperes
Standard 248-6, Class H
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
To order, specify LKN (250V) or LKS (600V) plus
ampere rating.

1
2
3
4
5

6
8**
10
12**
15

20
25
30
35
40

45
50
60
70
80

90
100
110
125
150

175
200
225*
250*
300*

350*
400*
450*
500*
600*

*These ampere ratings require two links per fuse.
**RLS Only.
Example part number (series & amperage): RLN 20

Recommended Fuse Blocks
LH250 series (for RLN series fuses)
LH600 series (for RLS series fuses)
Refer to the Blocks & Holders section of this catalog for additional information.

38

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

JLS Class J Fuses
600 VAC • Fast Acting • 1 – 600 Amperes

Space Saving
• JLS fuse characteristics are similar to KLNR/KLSR fast acting Class
RK1 fuses, but dimensionally are much smaller.

Safety
General Purpose Fuses

• 200,000 A.I.R. — Reliable interruption of all overcurrents up to
200,000 amperes.
• Extremely current-limiting — Stops damaging short-circuit current
faster than any mechanical protective device.
• Fast acting — Provides fast acting protection to equipment such as
variable speed drives, rectifiers and other equipment containing surge
sensitive components.

Longer Equipment Life
• Current-limiting design reduces damage to equipment caused by
heating and magnetic effects of short-circuit currents.

Economical
• Extremely current-limiting design often permits use of readily
available, less costly equipment.
• Manufacturers of equipment containing dual voltage devices can
simplify manufacturing and reduce inventory by standardizing on 600
volt JLS fuses and Class J fuse blocks for all AC voltage ratings.
JLS series fuses provide space saving, fast acting overload and shortcircuit protection for non-inductive loads. When used for motors or other
inductive loads, the ampere rating of JLS series fuses must be increased
to prevent nuisance opening on in-rush currents. In such applications, JLS
fuses may provide only short-circuit protection. Consider using Littelfuse
POWR-PRO® JTD or JTD_ID series time-delay fuses in such circuits.

Applications

Easy to use
• 200,000 A.I.R. rating minimizes need for short-circuit calculations.
NOTE: Littelfuse JLS fuses are not time-delay fuses. For applications
where short-duration surges and spikes may cause nuisance fuse
opening, consider the use of Littelfuse POWR-PRO JTD or JTD_ID
series time-delay fuses.

General purpose circuits with little or no motor load.
Resistive loads, such as resistance electric heat.
Loads requiring fast acting overload protection, such as equipment
containing solid-state devices.

Specifications
Voltage Ratings:
Interrupting Ratings:
Ampere Range:
Approvals:

Ampere Ratings
600 Volts AC
200,000 amperes rms symmetrical
1 – 600 amperes
Standard 248-8, Class J
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
QPL: Federal Specification No: WF-1814

1
3
6
10
15
20

25
30
35
40
45
50

60
70
80
90
100
110

125
150
175
200
225
250

300
350
400
450
500
600

Example part number (series & amperage): JLS 110

Recommended Fuse Blocks
LPSJ series, LJ600 series
Refer to the Blocks and Holders section of this catalog for additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

39

General Purpose Fuses

JLS Class J Fuses
600 VAC • Fast Acting • 1 — 600 Amperes

C
G

F

D
General Purpose Fuses

Dimensions In Inches (mm in parentheses)

Refer to
Fig. No.

A

B

14

C

1 – 30

1

2 ⁄ (57.2)

—

12

35 – 60

1

2 3 ⁄ 8 (60.3)

—

5 8

70 – 100

2

2 5 ⁄ 8 (66.7)

3 17⁄32 (89.7)
9 32

3 3 ⁄8 (85.7)

450 – 600

2

3 3 ⁄4 (95.3)

D

E

F

G

H

13 16

(20.6)

—

—

—

—

⁄ (15.9)

11 ⁄16 (27.0)

—

—

—

—

3 23 ⁄ 32 (94.5)

4 5 ⁄ 8 (117.5)

1 (25.4)

3 4

9 32

12

18

⁄ (12.7)

⁄

(7.1)

18

⁄ (3.2)

(113.5)

5 ⁄ (146.1)

1 ⁄ (38.1)

1 ⁄ (28.6)

⁄

(7.1)

3 16

51⁄8 (130.2)

5 3 ⁄ 8 (136.5)

7 1⁄ 8 (181.0)

2 (50.8)

15 ⁄8 (41.3)

13 32

⁄

(10.3)

1 4

527⁄ 32 (148.4)

6 5 ⁄ 32 (156.4)

8 (203.2)

2 1⁄2 (63.5)

2 (50.8)

17 32

(13.5)

3 8

(108.7)

4 ⁄

3 4

⁄ (19.1)

9 32

4⁄

15 32

⁄

⁄

⁄

(4.8)

⁄ (6.4)
⁄ (9.5)

600A

2

400A

225 – 400

200A

3 (76.2)

100A

2

60A

110 – 200

30A

E

Fig. 2

Fig. 1

Amperes

H

A
B
C
D

A

1000
800
600

1000000
800000
600000

400
300

400000
300000

200

200000
100
80
60

100000
80000
60000

40
30

PEAK LET-THRU IN AMPERES

10
8
6
4
3
2
1
.8
.6
.4
.3

20000

200A
100A
60A

10000
8000
6000

30A

4000
3000
2000

400
300

.1
.08
.06

200

.04
.03

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

100
60000
80000
100000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

300
400

200

60
80
100

30
40

20

8
10

30000
40000

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

CURRENT IN AMPERES

40

300
400

100

.02

5

400A

1000
800
600

.2

.01

600A

40000
30000

200

TIME IN SECONDS

20

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

JLLN/JLLS POWR-T™ Class T Fuses
300/600 VAC • Fast-Acting • 1 – 1200 Amperes

Applications

General Purpose Fuses

Littelfuse Class T fuses can be used in applications that require fastacting protection, such as equipment containing variable speed drives,
rectifiers, and other surge-sensitive components. Main switches
containing Class T fuses may be used to provide protection to individual
electric services and meter stacks. Molded case circuit breaker load
centers and Panelboards also will have increased interrupting ratings
when “series rated” with Class T fuses.

Features/Benefits
Space-Saving – Switch enclosures, fuse pullouts, and other equipment
using Class T fuses are usually more compact. Typical three-pole Class
T fuse blocks require less than 50% of the panel space required by
similar Class R blocks.
Longer Equipment Life and Increased Safety – Class T fuses provide
fast, reliable protection against overcurrents up to 200,000 amperes.
Extremely current-limiting design minimizes the damaging heating and
magnetic effects caused by short-circuit currents.

Space saving POWR-T fuses are the most compact fuses available in
ratings above 30 amperes — less than one-third the size of comparable
Class R fuses. When rated in accordance with the NEC®, POWR-T fuses
provide fast acting overload and short-circuit protection for non-inductive
circuits and equipment. Used in inductive circuits, the ampere rating of
POWR-T fuses must be increased to prevent opening on in-rush currents.
In such instances, POWR-T fuses may provide only short-circuit protection.

Specifications
Voltage Ratings:

Interrupting Ratings:

Ampere Range:
Approvals:

Optional Mounting Types – In addition to the Class T dimensions,
Littelfuse offers select ratings with PC board mounting tabs for specialty
applications. PC board mount versions are UL Recognized. Contact the
factory for more information.
NOTE: JLLN Class T 300 volt fuses are UL Listed for circuits not
exceeding 300 volts to ground. However, since UL does not include
testing 300 volt Class T fuses on 277/480 volt three-phase bolted faults,
Littelfuse does not recommend using 300 volt Class T fuses where
phase-to-phase voltage exceeds 300 volts.

Ampere Ratings
AC: 300 Volts (JLLN); 600 Volts (JLLS)
DC: 125 Volts (JLLN 1 – 30A)
160 Volts (JLLN 35 – 60A)
125 Volts (JLLN 110 – 1200A)
300 Volts (JLLS)
AC: 200,000 amperes rms symmetrical
DC: 20,000 amperes
(JLLN 110 – 1200A)
(JLLS 1 – 1200A)
1– 1200 amperes
AC: Standard 248-15, Class T
UL Listed (File No: E81895):
JLLN/JLLS (1 – 800A)
UL Recognized (File No: E71611):
JLLS (900 – 1200A)
CSA Certified (File No: LR29862):
JLLN/JLLS (1 – 600A)
DC: UL Listed (File No: E81895):
JLLN (110 – 1200A)
Littelfuse self-certified: JLLN 1-60A
JLLS (1 – 1200A)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

1
2
3
6
10
15
20
25

30
35
40
45
50
60
70
80

90
100
110
125
150
175
200
225

250
300
350
400
450
500
600
700

800
900*
1000
1100
1200

* JLLS only
Example part number (series & amperage): JLLS 100
Note: Contact the factory for RoHS compliant Class T fuses.

Recommended Fuse Blocks
LT300 series (for JLLN series fuses)
LT600 series (for JLLS series fuses)
LSCR002 (for JLLN/JLLS 700-1200A fuses)
Refer to the Blocks and Holders section of this catalog for additional information.

www.littelfuse.com

41

General Purpose Fuses

JLLN/JLLS POWR-T™ Class T Fuses
300/600 VAC • Fast Acting • 1 – 1200 Amperes

C
D

General Purpose Fuses

D

B
C

A

C

F

F

E
A

A

Fig. 1

Refer to
Fig. No.

Amperes
1 – 30

1
1

35 – 60

2

70 – 100

3

110 – 200

3

225 – 400

3

450 – 600

3

700 – 800

3

900 – 1200

3

Fig. 2

D

Fig. 3

Dimensions in Inches (mm in parentheses)

Series

A

B

JLLN

78

⁄ (22.2)

JLLS

11⁄ 2 (38.1)

JLLN

78

JLLS

9 16

1⁄

JLLN

2 5 ⁄32 (54.8)

⁄ (22.2)

61 64

C

—

9 32

⁄

—

9 32

⁄

9 32

—
13 16

(39.7)

⁄

(20.6)

19 ⁄ 16 (39.7)
23 64

D

E

F

(7.1)

⁄

(10.3)

—

—

—

(7.1)

9 16

⁄

(14.3)

—

—

—

⁄

(7.1)

9 16

(14.3)

13 32

(10.3)

⁄

⁄

1 (25.4)
13 16

(59.9)

3 4

13 16

⁄ (19.1)

⁄

(20.6)

—
1 16
27 32

(21.4)

9 32

⁄

(7.1)

1 8

(41.7)

9 32

⁄

(7.1)

1 8

(21.4)

11 32

⁄

(8.7)

3 16

⁄

(4.8)

11 32

(8.7)

3 16

(4.8)

13 32

⁄

(10.3)

1 4

13 32

⁄

41 64

JLLN

2 7⁄ 16 (61.9)

111 ⁄16 (42.9)

78

11 ⁄16 (27.0)

JLLS

3 1⁄4 (82.6)

21⁄ 2 (63.5)

78

⁄ (22.2)

11 ⁄16 (27.0)

121 ⁄ 32 (42.1)

JLLN

2 3 ⁄4 (69.9)

127⁄ 32 (46.8)

1 (25.4)

15 ⁄ 16 (33.3)

53 64

JLLS

3 5 ⁄8 (92.1)

223 ⁄ 32 (69.1)

1 (25.4)

119 ⁄32 (40.5)

1 16

3⁄

JLLN

(77.8)

1 32

2⁄

⁄ (19.1)

⁄

⁄ (22.2)

1 4

19 32

(51.6)

1 ⁄ (31.8)

1 ⁄

(20.6)

(40.5)

JLLS

3 63 ⁄ 64 (101.2)

2 61 ⁄ 64 (75.0)

11 ⁄4 (31.8)

2 1 ⁄ 16 (52.4)

JLLN

3 3 ⁄8 (85.7)

2 7⁄32 (64.3)

13 ⁄4 (44.5)

2 1 ⁄ 16 (52.4)

JLLS

4 21 ⁄64 (109.9)

311 ⁄64 (80.6)

13 ⁄4 (44.5)

21⁄ 2 (63.5)

JLLN

4 (101.6)

JLLS

5.27 (133.9)

17 32

2 ⁄

12

1 ⁄

27 32

⁄

⁄

(21.0)

123 ⁄32 (43.7)
⁄ (22.2)

⁄

(12.3)

⁄

(7.9)

149 ⁄ 64 (44.8)

31 64

⁄

(12.3)

5 16

(7.9)

⁄ (22.2)

35 64

⁄

(13.9)

3 8

155 ⁄64 (47.2)

35 64

(13.9)

3 8

(15.5)

7 16

78

1 32

3.80 (96.5)

2 (50.8)

2.63 (66.8)

2.30 (58.4)

60A

100A

200A

400A

600A

800A

775

1,100

1,650

3,500

4,000

5,000

10,000

900

1,000

1,400

2,100

4,400

5,100

15,000

1,000

1,100

1,600

2,400

5,000

5,900

⁄ (6.4)

1 4

1⁄

700

⁄

5 16

2 ⁄ (63.5)

30A

⁄ (3.2)

(10.3)

2 (50.8)

5,000

⁄

⁄ (3.2)

31 64

78

(64.3)

Short
Circuit
Current*

—
—

(1.6)

2 ⁄

2 ⁄

—
13 ⁄ 32 (27.8)

⁄

JLLS

(75.0)

G

13 32

3 4

Current-Limiting Effects of JLLN (300V) fuses

(26.2)

⁄

⁄

39 64

⁄

⁄ (6.4)

⁄

⁄ (9.5)
⁄ (9.5)

⁄

0.67 (15.5)

(11.1)

0.44 (11.2)

Current-Limiting Effects of JLLS (600V) fuses

1200A

Short
Circuit
Current*

30A

60A

100A

200A

400A

600A

800A

5,000

5,000

750

1,225

1,400

2,850

4,600

5,000

5,000

5,000

6,750

8,250

10,000

945

1,525

1,700

3,600

6,000

8,500

9,400

10,000

7,750

10,000

15,000

1,050

1,700

2,000

4,050

6,600

9,750

10,500 13,000

10,500 11,000 14,750

Apparent RMS Symmetrical Current for Various fuse ratings

Apparent RMS Symmetrical Current for Various fuse ratings
1200A

20,000

1,100

1,250

1,800

2,700

5,500

6,500

8,750

11,000

20,000

1,150

1,900

2,200

4,450

7,250

25,000

1,230

1,300

1,950

2,900

6,000

7,000

9,500

12,000

25,000

1,300

2,050

2,400

4,800

8,000

11,500 12,500 15,500

30,000

1,300

1,475

2,050

3,100

6,400

7,500

10,000 12,500

30,000

1,375

2,150

2,450

5,000

8,250

12,000 13,750 16,500

35,000

1,330

1,575

2,150

3,300

6,750

7,750

10,500 13,500

35,000

1,400

2,250

2,600

5,100

8,500

13,000 14,000 17,000

40,000

1,430

1,600

2,300

3,500

7,000

8,000

11,000 14,000

40,000

1,425

2,400

2,800

5,200

8,700

14,000 14,750 18,000

50,000

1,500

1,750

2,400

3,700

7,500

8,750

12,000 15,000

50,000

1,600

2,450

2,900

6,000

9,500

14,500 16,000 20,000

60,000

1,700

1,900

2,700

4,000

8,000

9,500

12,500 16,000

60,000

1,650

2,625

3,100

6,250

10,000 15,500 17,300 21,000

80,000

1,850

2,100

2,800

4,400

9,000

10,500 14,000 17,500

80,000

1,825

2,800

3,400

7,000

11,000 17,000 18,750 23,000

100,000

2,000

2,250

3,150

4,800

9,750

11,500 15,000 18,500

100,000

2,000

3,100

3,700

7,250

12,000 18,000 20,000 25,000

150,000

2,300

2,600

3,600

5,500

11,000 13,000 17,500 22,000

150,000

2,250

3,400

4,300

8,500

13,000 21,000 23,000 28,500

200,000

2,600

2,800

3,900

6,000

12,000 14,500 19,500 24,000

200,000

2,450

3,800

4,600

9,000

15,000 23,000 25,000 31,000

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves
42

G

B

* Prospective RMS Symmetrical Amperes Short-Circuit Current
Note: Data Derived from Peak Let-Thru Curves

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

JLLN/JLLS POWR-T™ Class T Fuses
300/600 VAC • Fast Acting • 1 – 1200 Amperes

40
30

40
30

20

20

10
8
6

10
8
6

4
3
2
1
.8
.6

800A

600A

100A

4
3
2

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

200

60
80
100

30
40

20

8
10

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

2000

600
800
1000

.01

300
400

.02

.01

200

.04
.03

.02

60
80
100

.04
.03

30
40

.1
.08
.06

20

.2

.1
.08
.06

8
10

.4
.3

.2

5

.4
.3

5

1
.8
.6

CURRENT IN AMPERES

CURRENT IN AMPERES

JLLS

1000000
800000
600000

1000000
800000
600000

400000
300000

400000
300000

200000

200000
100000
80000
60000

1200A
800A
600A
400A

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

200000

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

100
3000
4000

100
2000

200

600
800
1000

200

300
400

400
300

200

400
300

100

1000
800
600

60000
80000
100000

2000

1000
800
600

© 2005 Littelfuse • POWR-GARD™ Products Catalog

30A

4000
3000

30000
40000

2000

100A
60A

20000

4000
3000

10000
8000
6000

6000
8000
10000

60A
30A

3000
4000

100A

2000

10000
8000
6000

200A

600
800
1000

200A

400A

20000

300
400

20000

800A
600A

40000
30000

PEAK LET-THRU IN AMPERES

40000
30000

200

100000
80000
60000

100

JLLN

PEAK LET-THRU IN AMPERES

400A

100
80
60

600
800
1000

200

100
80
60

200A

200

300
400

400
300

TIME IN SECONDS

400
300

TIME IN SECONDS

1000
800
600

General Purpose Fuses

1000
800
600

60A

30A

1200A

800A

400A
600A

200A

60A

100A

JLLS
30A

JLLN

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

www.littelfuse.com

43

General Purpose Fuses

SLC Class G Fuses
480 VAC, 600 VAC • Medium Time-Delay • 1/2 – 60 Amperes
Dimensions in Inches (mm in parentheses)

Refer to
Fig. No.

Amperes
12

A
15 ⁄16 (33.3)
113 ⁄ 32 (35.7)
15 ⁄ 8 (41.3)
2 1⁄4 (57.2)

1
1
1
1

General Purpose Fuses

⁄ – 15
20
25, 30
35 – 60

3 8

⁄
3 8
⁄
3 8
⁄
3 8
⁄

B
(9.5)
(9.5)
(9.5)
(9.5)

C
⁄ (7.1)
9 32
⁄ (7.1)
9 32
⁄ (7.1)
12
⁄ (12.7)
9 32

13 32

⁄
13 32
⁄
13 32
⁄
13 32
⁄

D
(10.3)
(10.3)
(10.3)
(10.3)

A
D

C
B

2A
3A
4A
5A
6A
8A
10A
12A
15A
20A
25A
30A
35A
40A
45A
50A
60A

1A

1/2A

Fig. 1

1000
800
600
400
300
200
100
80
60

• Current-limiting – Reduces damage to equipment caused by heating
and magnetic effects of short-circuit currents.
• 100,000 A.I.R. – Reliable interruption of all overcurrents up to
100,000 amperes.
• Time-Delay – Allows fuses to be sized closer to actual equipment
requirements and may reduce downtime caused by power surges.

20
10
8
6
4
3
2
1
.8
.6
.4
.3
.2
.1
.08
.06
.04
.03
.02

Note: For applications where greater time-delay is required, or where
ratings exceed 60 amperes, consider selecting Littelfuse time-delay
Class RK1, RK5, J or CC fuses.

Specifications
600 Volts AC (1⁄ 2 – 20A)
480 Volts AC (25 – 60A)
Interrupting Ratings: 100,000 amperes rms symmetrical
12
Ampere Range:
⁄ – 60 amperes
Approvals:
Standard 248-5, Class G
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
QPL: Federal Specification No: WF-1814
Voltage Ratings:

44

2000

3000
4000

600
800
1000

200

300
400

60
80
100

30
40

20

6
8
10

3
4

2

1

.01

6000
8000
10000

Features/Benefits

40
30

TIME IN SECONDS

The compact design of Littelfuse SLC series Class G fuses offers a cost
effective, space saving alternative to other fuse classes. The unique
design of the SLC series provides superior time-delay characteristics
over competitive products, which can increase system reliability and
minimize downtime. Class G fuses meet NEC requirements for branch
circuit protection and vary in length to prevent over-fusing when used
with the appropriate Class G fuse block.

CURRENT IN AMPERES

Ampere Ratings
12

⁄
3
6
15
1
4
8
20
2
5
10
25
Example part number (series & amperage): SLC 10

30
35
40

45
50
60

Recommended Fuse Blocks
LG300 series; L300G30 (for 25 and 30 amp fuses)
Refer to the Blocks & Holders section of this catalog for additional information.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

Class CC and Class CD Fuses
600 VAC • 1/10 – 60 Amperes

Applications

General Purpose Fuses

Three types of Class CC fuses, specifically designed to protect different
types of components
1) Motor protection — CCMR series; dual-element, time-delay fuses
specifically designed to protect motor circuits up to 40 HP**.
2) Small transformer protection (control power transformers) — KLDR
series, time-delay fuses designed to withstand the high magnetizing
in-rush of transformers.
3) General purpose protection of equipment requiring fast overload
protection — KLKR series, fast-acting fuses used for protection
of equipment containing solid-state devices or other electronic
components requiring fast response on overloads.

Safety
• 200,000 A.I.R. — Reliable interruption of all overcurrents up to
200,000 amperes.
• Extremely current-limiting — Reduces damage caused by heating
and magnetic effects of short-circuit currents. Stops damaging shortcircuit currents faster than any mechanical protective device.

Space Saving
Compared to other UL Listed fuses, Class CC has the most currentlimiting fuse design available, rating for rating. Because they are
physically compact, they provide this superior protection in a fraction
of the space required by other fuse classes. For example, when 600V
three-pole, 30 ampere Class R fuse blocks are replaced by Littelfuse
Class CC fuse blocks, panel mounting space is reduced approximately
70%. This is especially important when a panel contains many fuses to
protect multiple circuit components.

Specifications
Voltage Ratings:

Interrupting Ratings:

Ampere Range:

Approvals:

• Class CC and CD fuses are the smallest 600V, 200,000 A.I.R. fuses
approved for branch circuit protection.

Economical
• Current-limiting design often permits use of readily available, less
costly equipment.

Recommended Fuse Blocks
AC: 600 Volts
DC: 250 – 500 Volts (CCMR) †
300 Volts (KLDR)
300 Volts (KLKR)
AC: 200,000 amperes
rms symmetrical
DC: 20,000 amperes
CCMR: 2 ⁄10 – 60 amperes
KLDR: 1⁄10 – 30 amperes
KLKR: 1⁄10 – 30 amperes
AC: Standard 248-4, Class CC
UL Listed 1⁄10 -30 Amps (File No: E81895)
Standard 248, Class CD
UL Listed 35-60 Amps (File No: E71611)
CSA Certified 1⁄10 -30 Amps
(File No: LR29862)
DC: Littelfuse Self-certified

LPSC series (for 1⁄10 –30A)
L60030C series (for 1⁄10 –30A)
L60060C series (for CCMR 35–60A)
Refer to the Blocks and Holders section of this catalog for additional information.
†Refer to the POWR-PRO® section for additional information.

** Consult the Motor Protection Tables in the Fuseology section for specific
motor sizing information

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

.25"
(6.4 mm)

1.50"
(38.1 mm)

.41"

0-30A

(10.3 mm)

.125"
.50"

(3.2 mm)

(12.7 mm)

35-60A

+

.850 -.020

1.880 REF.

45

General Purpose Fuses

Class CC and Class CD Fuses
600 VAC • 1/10 – 60 Amperes
CCMR Series

General Purpose Fuses

For space saving protection of motor
circuits up to 40 HP**, we recommend
Littelfuse POWR-PRO® CCMR series fuses.
These fuses are the only true dual-element
time-delay CC fuses specifically engineered
for motor branch circuit protection. They provide
Type 2 “No Damage” protection to both
NEMA-rated and the more sensitive IEC
(International Electrotechnical Commission)
type motor circuit components.

For more information on CCMR series Class
CC fuses, see the CCMR series pages in the
POWR-PRO section of this catalog.
1
⁄10 – 30A:
UL Listed Class CC
35 – 60A:
UL Listed Class CD

Ampere Ratings
2

⁄10
⁄4
3
⁄10
1
⁄2
6
⁄10
8
⁄10
1
1

CCMR series fuses are now available in larger
sizes — from 35 to 60 amperes! No other
600V fuse is available with this current
carrying capacity in a package this small.
**Consult the Motor Protection Tables in the Fuseology section for specific motor sizing information

11⁄4
14 ⁄10
11⁄2
16 ⁄10
18 ⁄10
2
2 1⁄4

2 1⁄2
2 8 ⁄10
3
3 2 ⁄10
31⁄2
4
41⁄2

5
5 6 ⁄10
6
6 1⁄4
7
7 1⁄ 2
8

9
10
12
15
171⁄ 2
20
25

30
35
40
45
50
60

Example part number (series & amperage): CCMR 30

KLDR Series
KLDR fuses are time-delay fuses specifically
designed for the protection of control
transformers, solenoids and similar inductive
components with high magnetizing currents
during the first half-cycle. They closely match
most control power transformer characteristics,
which permits the fuses to be sized in
accordance with the latest revisions of UL 508
(Industrial Control) and UL 845 (Motor Control
Centers). When the time delay of KLDR fuses
is adequate to carry motor starting current, they
provide excellent protection of motor branch
circuits containing IEC or NEMA rated motor
controllers or contactors.

Ampere Ratings
1

⁄10
⁄8
15
⁄100
⁄ 16
2
⁄10
1
⁄4
3
⁄10
4
⁄10
1
⁄2
1

6

⁄10
⁄4
8
⁄10
1
11⁄8
11⁄4
14 ⁄10
11⁄2
1 6 ⁄10
3

18 ⁄10
2
2 1⁄ 4
21⁄2
2 8 ⁄10
3
3 2 ⁄10
3 1⁄2
4

4 1⁄2
5
5 6 ⁄10
6
6 1⁄4
7
7 1⁄2
8
9

10
12
15
17 1⁄2
20
25
30

Example part number (series & amperage): KLDR 5 6 ⁄10

KLKR Series
KLKR series Class CC fuses are fast acting
fuses intended for general purpose branch
circuit protection. Their compact size, fast
acting overload response, and highly currentlimiting design make them ideal for use in
OEM equipment and control panels. Solid state
devices such as SCRs and other electronic
equipment generally require fast acting
protection.

46

www.littelfuse.com

Ampere Ratings
1

⁄10
⁄8
2
⁄10
1
⁄4
3
⁄10
1

1

⁄2
⁄4
1
11⁄ 2
2
3

2 1⁄2
3
3 1⁄ 2
4
5

6
7
8
9
10

12
15
20
25
30

Example part number (series & amperage): KLKR 25

© 2005 Littelfuse • POWR-GARD™ Products Catalog

General Purpose Fuses

Class CC and Class CD Fuses
600 VAC • 1/10 – 60 Amperes

400
300

200

200

100
80
60

100
80
60

40
30

40
30

20

20

10
8
6

10
8
6

TIME IN SECONDS

400
300

4
3
2
1
.8
.6

2A
3A
4A
5A
6A
8A
9A
10A
12A
15A
20A
25A
30A

1 1/2A

2
1
.8
.6
.4
.3

.2

.2
.1
.08
.06

.04
.03

.04
.03

.02

.02

CURRENT IN AMPERES

600
800
1000

300
400

200

60
80
100

30
40

20

6
8
10

2

3
4

.6
.8
1

.3
.4

.2

.01
.1

600
800
1000

200

300
400

60
80
100

30
40

20

6
8
10

3
4

2

.6
.8
1

.3
.4

.2

.1

.01

CURRENT IN AMPERES

KLKR
1000000
800000
600000

400000
300000

400000
300000

200000

200000

100000
80000
60000

100000
80000
60000

40000
30000

40000
30000

200000

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

AVAILABLE FAULT CURRENT
SYMMETRICAL R. M. S. AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

60000
80000
100000

200000

60000
80000
100000

30000
40000

20000

6000
8000
10000

3000
4000

100
2000

100
600
800
1000

200

300
400

200

200

400
300

100

400
300

30000
40000

1000
800
600

20000

1000
800
600

6000
8000
10000

8A
6A
4A

30A
25A
20A
15A
12A

2000

3000
4000

2000

4000
3000

2000

10A

600
800
1000

4000
3000

10000
8000
6000

300
400

10000
8000
6000

20000

200

20000

PEAK LET-THRU IN AMPERES

1000000
800000
600000

100

KLDR

PEAK LET-THRU IN AMPERES

3/4A
1A

1/2A

4
3

.4
.3

.1
.08
.06

2/10A
1/4A
3/10A

10A

1000
800
600

General Purpose Fuses

1000
800
600

TIME IN SECONDS

1/10A
1/8A

KLKR

2A
2 1/2A
3A
4A
6 1/4A
8A

1.8A

1/8A
2/10A

KLDR

3/10A
1/2A
6/10A
3/4A
1A

For performance data on Littelfuse CCMR series Class CC fuses, see the CCMR pages in the POWR-PRO® section of this catalog.

www.littelfuse.com

47

General Purpose Fuses

Plug Fuses
125 VAC • Time-Delay • 1/4 – 30 Amperes
Edison-base Plug fuses
TOO Fuses are dual-element time-delay Edison-base fuses designed for
motor and motor branch circuit protection; also suitable for all general purpose
circuits. Use for replacement purposes only.
General Purpose Fuses

Ampere Ratings
3 10

⁄
⁄
12
⁄
6 10
⁄
8 10
⁄
4 10

1

1 1⁄8
1 1⁄4
14 ⁄10
1 6 ⁄10
18 ⁄10
2

2 1⁄4
2 1⁄2
2 8 ⁄10
3
3 2 ⁄10
31⁄2

4
4 1⁄2
5
5 6 ⁄10
6
6 1⁄4

7
8
9
10
12
14

15
20
25
30

TLO Fuses are medium time-delay Edison-base fuses designed for general
purpose branch circuit protection. See TOO and SOO fuses for motor
protection. Use for replacement purposes only.

Ampere Ratings
15

Littelfuse Plug fuses provide overcurrent protection to general purpose
circuits and small motor loads. Edison-base Plug fuses (TOO and TLO
series) feature metal threads similar to incandescent lamp bases. Type S
Plug fuses (SOO and SLO series) utilize a nonmetallic threaded base and
must be used with Type S adapters (SAO series). The National Electrical
Code permits Edison-base Plug fuses to be used for replacement
purposes only. Type S fuses and adapters prevent shunting open fuses
and over-fusing.

20

25

30

Type S Plug fuses
SOO Fuses are dual-element time-delay Type S fuses designed for motor and
motor branch circuit protection; also suitable for all general purpose circuits.

Ampere Ratings
SAO
Adapter Rating
SAO 1
SAO 11⁄4
SAO 16 ⁄10
SAO 2
SAO 21⁄ 2
SAO 3 2 ⁄10
SAO 4
SAO 5
SAO 61⁄ 4
SAO 8
SAO 15
SAO 20
SAO 30

Accepts
Fuse Ratings:
3 10
⁄ –1
11⁄8, 11⁄4
14 ⁄10, 16 ⁄10
18 ⁄10, 2
21⁄ 4, 21⁄ 2
2 8 ⁄10, 3 2 ⁄10
31⁄2, 4
41⁄2, 5
31⁄2, 61⁄4
7, 8
7, 8, 9 10, 12, 14, 15
20 only
20, 25, 30

Other SOO Fuse
Ratings Which Fit
—
3 10
⁄ –1
3 10
⁄ – 11⁄4
—
18 ⁄10, 2
18 ⁄10 – 21⁄ 2
—
31⁄ 2, 4
31⁄2 – 5
—
7, 8, 9, 10
—
—

14

⁄
⁄
4 10
⁄
12
⁄
6 10
⁄
8 10
⁄
3 10

1
11⁄8
1 1⁄4
14 ⁄10
16 ⁄10
18 ⁄10

2
2 1⁄4
2 1⁄2
2 8 ⁄10
3
3 2 ⁄10

3 1⁄2
4
4 1⁄2
5
5 6 ⁄10
6

6 1⁄4
7
8
9
10
12

14
15
20
25
30

SLO Fuses are medium time-delay Type S fuses for general purpose branch
circuit protection.

Ampere Ratings
15

20

25

30

Specifications
Voltage Rating:
Interrupting Rating:
Approvals:

125 VAC
10,000 amperes rms symmetrical
UL Listed Plug Fuses, Standard UL 248-11

Note: See NEC Article 240-V for additional information on Plug fuse applications.

48

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget Fuses

50-54

Electronic Fuses

55-59

Automotive Fuses

60-62

www.littelfuse.com

Midget & Electronic Fuses

Midget Fuses
Supplementary Overcurrent Protection

KLK Fuses
Fast-Acting • 600 VAC

Fast-acting, high-interrupting capacity, current-limiting type fuse. Especially suited for control circuits,
street lighting, H.I.D. lighting, computers, and other
applications without high in-rush currents.

600 Volts AC
500 Volts DC
Interrupting Rating: UL Listed 100,000 amperes rms
symmetrical
(Capable of 200,000 amperes)
13
⁄ 32" x 11⁄2"
Dimensions:
Example part number (series & amperage): KLK 11 ⁄ 2

Midget & Electronic Fuses

Voltage Rating:

KLKD Fuses
Fast-Acting • 600 VAC/DC

Fast acting, high interrupting capacity, currentlimiting type fuse. Especially suited for DC control
circuits, street lighting, H.I.D. lighting, computers,
and other applications.

Voltage Rating:
600 Volts AC/DC
Interrupting Rating: AC: 100,000 amperes rms
symmetrical;
DC: 10,000 amperes
13
⁄ 32" x 11⁄2"
Dimensions:
Example part number (series & amperage): KLKD 30

FLM Fuses
Time-Delay • 250 VAC

Use FLM 250 volt time-delay fuses to protect
control circuit transformers, solenoids, and other
circuits with high in-rush currents. Excellent for
supplemental protection of small motors. For motor
branch circuit protection, Refer to Class CC fuses.

Voltage Rating:

125 Volts AC
125 Volts DC self-certified @ 10KA
Interrupting Rating: AC: 10,000 amperes rms
symmetrical.
13
⁄ 32" x 11⁄2"
Dimensions:
Example part number (series & amperage): FLM 15

Ampere Ratings:
1

⁄10
⁄8
2
⁄10
1
⁄4
3
⁄10
1
⁄2
3
⁄4

1
11⁄ 2
2
2 1⁄ 2
3
3 1⁄ 2
4

1

Approvals:

5
6
7
8
9
10
12

15
20
25
30

Standard 248-14
UL Listed 3/10-30A (File No: E10480)
CSA Certified 3/10-30A (File No: LR29862)
Versions available to meet
MIL-F-5160/60, QPL F60C:
Contact Factory.

Ampere Ratings:
1

⁄10
⁄8
2
⁄10
1
⁄4
3
⁄10
1
⁄2
3
⁄4

1
11⁄ 2
2
2 1⁄2
3
3 1⁄2
4

1

Approvals:

5
6
7
8
9
10
12

15
20
25
30

Standard 248-14
UL Listed 3/10-30A (File No: E10480)
CSA Certified 3/10-30A (File No: LR29862)

Ampere Ratings:
1

⁄10
⁄100
2
⁄10
1
⁄4
3
⁄10
4
⁄10
1
⁄2
6
⁄10
8
⁄10
1

15

Approvals:

11⁄8
11⁄ 4
1 4 ⁄10
11⁄2
1 6 ⁄10
1 8 ⁄10
2
2 1⁄4
2 1⁄ 2
2 8 ⁄10

3
3 2 ⁄10
3 1⁄2
4
4 1⁄ 2
5
5 6 ⁄10
6
6 1⁄ 4
7

8
9
10
12
15
20
25
30

Standard 248-14
UL Listed (File No: E10480)
CSA Certified (File No: LR29862)

Recommended Fuse Blocks
L60030M and LPSM series. Refer to the Blocks & Holders section of this catalog for additional information.

50

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

Midget Fuses
Supplementary Overcurrent Protection

FLQ Fuses
Time-Delay • 500 VAC

These 500 volt time-delay fuses provide excellent
supplemental protection of control power
transformers, solenoids, and circuits with high
inrush currents. UL and CSA 500 volt ratings
permit use on 480 volt circuits. FLQ fuses also
provide supplemental protection to small motors.
For motor branch circuit protection, refer to Class
CC fuses.

Voltage Rating:

BLN Fuses
Fast-Acting • 250 VAC

Fiber tube, 250 volt BLN fuses provide low-cost
protection for military applications and control
circuits.

Voltage Rating:
250 Volts AC
Interrupting Rating: 10,000 amperes rms
symmetrical
13
⁄32" x 11⁄2"
Dimensions:
Example part number (series & amperage): BLN 30

BLF Fuses
Fast-Acting • 125/250 VAC

Laminated tube BLF fuses are the lowest price
midget fuse. They are suitable for control circuit
and instrument protection in dry locations.

250 Volts AC: 1⁄2 – 15 amperes;
125 Volts AC: 20 – 30 amperes
Interrupting Rating: 10,000 amperes rms
symmetrical
13
⁄32" x 11⁄2"
Dimensions:
Example part number (series & amperage): BLF 5
Voltage Ratings:

8

1

⁄10
⁄8
15
⁄100
3
⁄16
2
⁄10
1
⁄4
3
⁄10
4
⁄10
1
⁄2
6
⁄10
Approvals:

3 2 ⁄10
3 1⁄ 2
4
41⁄ 2
5
5 6 ⁄10
6
6 1⁄ 4
7
8

⁄10
1
11⁄8
11⁄4
11⁄ 2
1 6 ⁄10
2
2 1⁄ 4
2 1⁄ 2
3

1

9
10
12
14
15
20
25
30
Midget & Electronic Fuses

500 Volts AC
300 Volts DC self-certified @ 10KA
Interrupting Rating: 10,000 amperes rms
symmetrical
13
⁄32" x 1 1⁄2"
Dimensions:
Example part number (series & amperage): FLQ 1 ⁄ 2

Ampere Ratings:

Standard 248-14
UL Listed (File No: E10480)
CSA Certified (File No: LR29862)

Ampere Ratings:
1
2
3
Approvals:

4
5
6

8
10
12

15
20
25

30

Standard 248-14
UL Listed (File No: E10480)
CSA Certified (File No: LR29862)
Versions available to meet MIL-F-15160/9,
QPL F09A: Contact Factory

Ampere Ratings:
1

⁄2
1
11⁄2
2
2 1⁄ 2
Approvals:

3
4
5
6
6 1⁄ 4

7
8
9
10
12

15
20
25
30

Standard 248-14
UL Listed (File No: E10480)
CSA Certified (File No: LR29862)

Recommended Fuse Blocks
L60030M and LPSM series. Refer to the Blocks & Holders section of this catalog for additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

51

Midget & Electronic Fuses

Midget Fuses
Supplementary Overcurrent Protection

BLS Fuses
Fast-Acting • 250/600 VAC

BLS fuses are 13 ⁄ 8 " long in contrast to other midget
fuses which are 11 / 2 ". They provide space saving,
low cost protection to street lighting, metering,
control and electronic circuits.

600 Volts AC: 2 ⁄10 – 5 amperes;
250 Volts AC: 6 – 10 amperes
Interrupting Rating: 10,000 amperes rms
symmetrical
13
⁄ 32" x 13 ⁄ 8"
Dimensions:
Example part number (series & amperage): BLS 10
Midget & Electronic Fuses

Voltage Rating:

FLA Fuses
Time-Delay • 125 VAC

FLA fuses are 125 volt, pin-indicating time-delay
fuses for protection of control circuit transformers,
solenoids, and other circuits with high in-rush
currents. Metal indicating pin pops-out when fuse
opens, giving visual indication of blown fuse. Use
FLA fuses in conjunction with special fuseblocks
to operate mechanical signal switches or energize
alarm circuits. Fuses rated 12 amperes and above
have dual-tube construction.

Voltage Rating:
125 Volts AC
Interrupting Rating: 10,000 amperes rms
symmetrical
13
⁄ 32" x 11⁄ 2"
Dimensions:
Example part number (series & amperage): FLA 15
* Note: Dual tube construction

Ampere Ratings:
2

⁄10
⁄10
1
⁄2
3
⁄4
8
⁄10

1
11⁄ 2
16 ⁄10
18 ⁄10
2

4

Approvals:

3
4
5
6
7

8
10

Standard 248-14
UL Listed 2 ⁄ 10 -10 Amps (File No: E10480)
CSA Certified 1⁄2 – 5 Amps
(File No: LR29862)

Ampere Ratings:
1

⁄10
⁄100
2
⁄10
1
⁄4
3
⁄10
4
⁄10
1
⁄2
6
⁄10
8
⁄10
1

15

Approvals:

11⁄8
11⁄4
1 4 ⁄10
11⁄2
1 6 ⁄10
1 8 ⁄10
2
2 1⁄4
2 1⁄2
2 8 ⁄10

3
3 2 ⁄10
3 1⁄2
4
4 1⁄2
5
5 6 ⁄10
6
6 1⁄4
7

8
10
12*
15*
20*
25*
30*

Standard 248-14
UL Listed (File No: E10480)
CSA Certification Pending

Recommended Fuse Blocks
L60030M and LPSM series. Refer to the Blocks & Holders section of this catalog for additional information.

52

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

Midget Fuses
Supplementary Overcurrent Protection

KLQ Series Fuses

The Littelfuse KLQ series is designed to protect
gaseous vapor fixtures, HID ballasts, and other
electronic and lighting circuits. The KLQ is the
same physical size as the Littelfuse BLS, but has
more time-delay to handle transient and in-rush
currents.

FLU Series Fuses

The Littelfuse FLU series is designed specifically
for the protection of multimeters. The 1000 VAC/
VDC rating also makes the FLU ideal for a variety
of other applications.

1
1 6 ⁄10

2
3

5
6

Recommended Fuse Blocks:
L60030M Series. Refer to the Blocks & Holders section
of this catalog for additional information.
Ordering Information:
Example catalog number: KLQ005
Example system number: 0KLQ005.T

Midget & Electronic Fuses

Voltage Rating:
600 VAC
Interrupting Rating: 10,000 amperes
Approvals:
Standard 248-14 UL Listed
(File No: E10480)
13
⁄ 32" x 13 ⁄ 8"
Dimensions:

Ampere Ratings:

Ordering Information
Example catalog number: FLU011
Example system number: 0FLU011.T

Voltage Rating:
1000 VAC/VDC
44
⁄100 A: 10kA
Interrupting Rating:
11A: 20kA
Ampere Range:
FLU 44 ⁄100 =1A and FLU 11 = 15A
Approvals:
UL Recognized under the
components program.
(File No: E10480)
CSA Certified (File No: LR29862)
44
⁄100 A: 13 ⁄32" x 13 ⁄ 8"
Dimensions:
11A: 13 ⁄32" x 11⁄2"

LNNB “Dummy” Fuse

Also known as a “neutral”, the LNNB is actually
not a fuse. It is the same physical size as a
standard Midget fuse. The LNNB001 is a hollow
body design for use with standard fuse clips. The
LNNB002 is a solid body design for use with LEB/
LEX series inline style fuse holders.

Specifications
Dimensions:

13

⁄ 32" x 11⁄ 2"

Ordering Information
Example catalog number: LNNB001
Example system number: LNNB0001Z
Example catalog number: LNNB002
Example system number: LNNB0002Z

LNNB001

LNNB002

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

53

.01

54
.02

.01
.01

CURRENT IN AMPERES

200
200

100
80
60
100
80
60

40
30

20
20

10
8
6
10
8
6

4
3
4
3

2

1
.8
.6

.4
.3

.2

.1
.08
.06

.04
.03

.02

1
.8
.6
2

.4
.3

.2

.1
.08
.06

.04
.03

.02

.01

CURRENT IN AMPERES

www.littelfuse.com
60
80
100

30
40

20

600
800
1000

400
300

300
400

400
300

6000
8000
10000

1000
800
600

200

FLQ

3000
4000

CURRENT IN AMPERES

2000

1000
800
600

600
800
1000

.04
.03

.02

300
400

.04
.03

200

1
.8
.6

6
8
10

2

3
4

40
30

60
80
100

20

2

40
30

.6
.8
1

100
80
60

.3
.4

200

100
80
60

.2

4
3

.1

10
8
6

TIME IN SECONDS

3/4A
1A
1 1/2A
2A
2 1/2A
3A
3 1/2A
4A
5A
6A
7A
8A
9A
10A
12A
15A
20A
25A
30A

2/10A
1/4A
3/10A
1/2A

1/8A

3/4A
1A
1 1/2A
2A
2 1/2A
3A
3 1/2A
4A
5A
6A
7A
8A
9A
10A
12A
15A
20A
25A
30A

1/8A
2/10A
1/4A
3/10A
1/2A

400
300

30
40

.1
.08
.06

600
800
1000

200

20

8A
9A
10A
12A
14A
15A
20A
25A
30A

.2

.1
.08
.06

200
300
400

400
300

6
8
10

.4
.3

.2

60
80
100

30
40

20

1000
800
600

3
4

.4
.3

6
8
10

3
4

2

.6
.8
1

.3
.4

.2

1000
800
600

2

40
30

TIME IN SECONDS

15A
20A
25A
30A

8A
10A

2A

1 1/2A

1A

1/2A

1/4A

.1

TIME IN SECONDS

KLK

1

600
800
1000

300
400

200

60
80
100

30
40

20

6
8
10

3
4

2

.6
.8
1

.3
.4

1/10A
15/100A

FLM

.2

.1

TIME IN SECONDS

Midget & Electronic Fuses

Midget & Electronic Fuses

Midget Fuses

Supplementary Overcurrent Protection

KLKD

10
8
6

20

4
3

2

1
.8
.6

CURRENT IN AMPERES

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

Electronic Fuses
3AG/3AB Type
312/318 Series
3AG Fast Acting Fuse

Designed for fast acting protection of electronic
equipment and appliances. The “standard” fast
acting, glass tube fuse.

Ampere Ratings:
2

1

⁄100
⁄32
1
⁄ 16
1
⁄10
1
⁄8
15
⁄100

⁄10
⁄4
3
⁄10
3
⁄8
1
⁄2
6
⁄10
8
⁄10
3
⁄4

250V: 1⁄100 – 10A.
32V: 12 – 35A.
1
⁄ 4" x 11⁄ 4" (6.4 x 31.8mm)
Dimensions:
Order 312 series without leads.
Example part number (series & amperage): 312.375
Note: For fuses with axial leads, request 318 series.
Voltage Rating:

3AB Fast Acting Fuse

3

⁄ 16

To order a 3AG “Dummy” fuse request part number
310033.

Approvals: Standard 248-14, UL Listed 1⁄100 -10 Amps
and UL Listed 12 – 30 Amps per Standard UL 275. CSA
Certified through 30 Amps.

Similar to 312 series, but ceramic tube permits
additional ampere ratings: 250 volt ratings through
30 amps.

Ampere Ratings:
3

1

⁄8
⁄4
3
⁄8
1
⁄2

⁄4
1
2
3

1

Voltage Rating:
250V: 1⁄8 – 30A
1
⁄ 4" x 11⁄4" (6.4 x 31.8mm)
Dimensions:
Order 314 series without leads.
Example part number (series & amperage): 324.375
Note: For fuses with axial leads, request 324 series.

313/315 Series
®

3AG SLO-BLO Fuse

313 and 315 series fuses have time-delay in the
overload range, which provides superior protection
for inductive loads such as motors, transformers,
and solenoids.

Voltage Rating:
250V: 1⁄100 – 8A. 32V: 10 – 30A.
1
⁄ 4" x 11⁄4" (6.4 x 31.8mm)
Dimensions:
Order 313 series without leads.
Example part number (series & amperage): 313.500
Note: For fuses with axial leads, request 315 series.
To order a 3AG “Dummy” fuse request part number
310033.

326/325 Series
®

3AB SLO-BLO Fuse

12
15
20
25
30
35

The 326 series fuse has time-delay similar to the
313 series, but the ceramic body permits higher
voltage ratings for the 8 – 30 ampere sizes and
faster opening of short-circuits.

250V: 1⁄100 – 20A.
125V: 25 – 30A.
1
⁄ 4" x 11⁄4" (6.4 x 31.8mm)
Dimensions:
Order 326 series without leads.
Example part number (series & amperage): 326012
Note: For fuses with axial leads, request 325 series.
Voltage Rating:

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

4
5
6
7

8
10
12
15

Midget & Electronic Fuses

314/324 Series

0.175

2 1⁄ 2
3
4
5
6
7
8
10

1
11⁄ 4
11⁄2
1 6 ⁄10
1 3 ⁄4
1 8 ⁄10
2
2 1⁄ 4

1

1

20
25
30

Approvals: Standard 248-14, UL Listed and CSA
Certified 1⁄8 – 15 Amps. UL Recognized under the
Components Program and CSA Recognized under
the Component Acceptance Program 20 – 30 Amps.
Approved by MITI from 10 – 30 Amps.

Ampere Ratings:
1

⁄100
⁄ 32
4
⁄100
1
⁄16
1
⁄10
1
⁄8
1

15

⁄100
0.175
3
⁄16
2
⁄10
1
⁄4
3
⁄10

3

8

⁄8
⁄10
1
⁄2
6
⁄10
7
⁄10
3
⁄4

⁄10
1
12 ⁄10
11⁄4
11⁄ 2
1 6 ⁄10

4

1 8 ⁄10
2
2 1⁄4
2 1⁄2
2 8 ⁄10
3

3 2 ⁄10
4
5
6 1⁄4
7
8

10
12
15
20
25
30

Approvals: Standard 248-14, UL Listed and CSA Certified
1
⁄100 -8 Amps. UL Recognized under the Components Program
and CSA Recognized under the Component Acceptance
Program 10 – 30 Amps. MITI approved 1 – 5 Amps.

Ampere Ratings:
1

3

1

2

⁄100
⁄ 32
1
⁄16
1
⁄10
1
⁄8
15
⁄100
0.175

⁄ 16
⁄10
1
⁄4
3
⁄10
3
⁄8
4
⁄10
1
⁄2

6

⁄10
⁄10
3
⁄4
8
⁄10
1
1 2 ⁄10
11⁄4
7

11⁄ 2
1 6 ⁄10
2
2 1⁄2
2 8 ⁄10
3
3 2 ⁄10

4
5
6 1⁄4
7
8
10
12

15
20
25
30

Approvals: Standard 248-14, UL Listed 1⁄ 4 – 10 Amps.
UL Recognized under the Components Program 12-30
Amps. CSA Certified 1⁄4 – 30 Amps.

55

Midget & Electronic Fuses

Electronic Fuses
Indicating Types
229/230 Series
2AG SLO-BLO® Indicating Fuse

2AG indicating fuses instantly identify themselves
upon opening by showing a discoloration of their
glass bodies. Guesswork and time consuming circuit testing is eliminated. This unique design offers
the same quality performance characteristics as
the standard 2AG fuse design.

Midget & Electronic Fuses

Voltage Rating: 250V: 1⁄4 – 3 1⁄2 A; 125V: 4 – 7A
Dimensions: .177" x .57" (4.5 x 14.5mm)
For fuses with axial leads, request 230___S series.
Order 229___S series without leads.
Example part number (series & amperage): 22902.5S

313 Series
®

3AG SLO-BLO Indicating Fuse

3AG indicating fuses instantly identify themselves
upon opening by showing a discoloration of their
glass bodies. Guesswork and time consuming circuit testing is eliminated. This unique design offers
the same quality performance characteristics as
the standard 3AG fuse design.

Voltage Rating:
250V: 1⁄2 – 8A; 32V: 10A.
1
⁄ 4" x 11⁄4": (6.4 x 31.8mm)
Dimensions:
Example part number (series plus amperage, followed
by “ID”): 313007ID

215 Series (Type T)
5 x 20mm SLO-BLO® Fuse

Time-delay protection of electronic equipment and
appliances when fuses to International Standards
are required. Replacement fuses for foreign
equipment.

Voltage Rating:
250V AC
Design Standards: Meets IEC 60127-2, Sheet 5
Specification for Time Lag fuses.
Dimensions:
5mm x 20mm (.2 x .79 in.)
Example part number (series & amperage): 215.315
Note: For fuses with axial leads add “XE” extension to
the part number. Example 215.630XE

56

www.littelfuse.com

Ampere Ratings:
3

1

⁄4
.350
3
⁄8
1
⁄2
6
⁄10

⁄4
⁄10
1
11⁄ 4
11⁄ 2

2
2 1⁄4
2 1⁄2
3
3 1⁄2

8

4
5
6
7

Approvals: Standard 248-14, UL Listed and CSA
Certified 1⁄4 – 3 1⁄2 Amps. UL Recognized under the
Components Program and CSA Recognized under the
Component Acceptance Program 4 – 7 Amps.

Ampere Ratings:
1

⁄2
1

11⁄2
2

3
4

5
6 1⁄ 4

7
8

10

Approvals: Standard 248-14, UL Listed and CSA
Certified 1⁄2 – 8 Amps. The 10 Amp is UL Recognized
under the Components Program and CSA Recognized
under the Component Acceptance Program.

Ampere Ratings:
.200
.250
.315

.400
.500
.630

.800
1
1.25

1.6
2
2.5

3.15
4
5

6.3
8*
10*

*Available but not included in International Standards.
Interrupting Capacity: 1500A
Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program. SEMKO, VDE, and BSI approved
1 – 6.3 Amps. MITI approved 1 – 10 Amps.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

Electronic Fuses
5 x 20mm IEC Type
216 Series (Type F)
5 x 20mm Fast-Acting Fuse

Fast acting protection of electronic equipment and
appliances when fuses to International Standards are
required. Replacement fuse for foreign equipment.

Voltage Rating:
250V AC
Design Standards: Meets IEC 60127-2, Sheet 1
Specification for Fast-Acting Fuses.
Dimensions:
5mm x 20mm (.2 x .79 in.)
Example part number (series & amperage): 216.200

217 Series (Type F)
5 x 20mm Fast-Acting Fuse

Fast-acting protection of electronic equipment and
appliances when fuses to International Standards are
required. Replacement fuse for foreign equipment.

Voltage Rating:
250V AC
Dimensions:
5mm x 20mm (.2 x .79 in.)
Example part number (series & amperage): 217.050
Design Standards: Meets IEC 60127-2, Sheet 2
Specification for Fast Acting Fuses.
Note: For fuses with axial leads add “XE” extension to
the part number. Example 217.630XE

218 Series (Type T)
5 x 20mm SLO-BLO® Fuse

Time-delay protection of electronic equipment and
appliances when fuses to International Standards
are required. Replacement fuses for foreign
equipment.

Voltage Rating:
250V AC
Dimensions:
5mm x 20mm (.2 x .79 in.)
Example part number (series & amperage): 218.630
Design Standards: Meets IEC 60127-2, Sheet 3
Specification for Time Lag Fuses.
Note: For fuses with axial leads add “XE” extension to
the part number. Example 218.630XE

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

.050
.063
.080
.100

.125
.160
.200
.250

.315
.400
.500
.630

.800
1
1.25
1.6

2
2.5
3.15
4

5
6.3
8*
10*

*Available but not included in International Standards.
Interrupting Capacity: 1500A
Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program. SEMKO and VDE approved
through 6.3 Amps. BSI approved 1 – 6.3 Amps.

Midget & Electronic Fuses

Note: For fuses with axial leads add “XE” extension to
the part number. Example 216.630XE

Ampere Ratings:

Ampere Ratings:
.032 .080 .200 .500 1.25 3.15
8*
.040 .100 .250 .630
1.6
4
10*
.050 .125 .315 .800
2
5
15*
.063 .160 .400
1
2.5
6.3
*Available but not included in International Standards.
Interrupting Capacity: 35A or 10x rated current, whichever is greater.
Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program. SEMKO and VDE approved
through 6.3 Amps. BSI approved 0.4 – 6.3 Amps.

Ampere Ratings:
.032 .080 .200 .500 1.25 3.15
8*
.040 .100 .250 .630
1.6
4
10*
.050 .125 .315 .800
2
5
15*
.063 .160 .400
1
2.5
6.3
*Available but not included in International Standards.
Interrupting Capacity: 35A or 10x rated current, whichever is greater.
Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program. SEMKO and VDE approved
through 6.3 Amps. BSI approved 0.8 – 6.3 Amps.

57

Midget & Electronic Fuses

Electronic Fuses
5 x 20mm and 2AG Type
235 Series
5 x 20mm Fast-Acting fuse

5 x 20mm fuses designed to UL and CSA
standards. Fast Acting protection of electronic
equipment appliances.

Ampere Ratings:
3

1

⁄10
⁄8
2
⁄10
1
⁄4

Voltage Rating:
250V: 1⁄10 – 3A; 125V: 4 – 6A.
Dimensions:
5mm x 20mm (.2 x .79 in.)
Example part number (series & amperage): 235.600

Midget & Electronic Fuses

Note: For fuses with axial leads add “XE” extension to
the part number. Example 235.600XE

239 Series
5 x 20mm SLO-BLO® fuse

5 x 20mm fuses designed to UL and CSA
standards. For protection of electronic equipment
and appliances.

1 6 ⁄10
2
2 1⁄2
3

⁄10
⁄10
1
11⁄4
8

4
5
6

Approvals: Standard 248-14, UL Listed and CSA
Certified. MITI approved 1 – 5 Amps.

Ampere Ratings:
2

⁄10
⁄4
3
⁄10
1

Voltage Rating:
250V: 2 ⁄10 – 3A. 125V: 4A.
Dimensions:
5mm x 20mm (.2 x .79 in.)
Example part number (series & amperage): 239.400

7

⁄10
⁄10
1
⁄2
6
⁄10
4

1

4

⁄10
⁄2
6
⁄10
1

7

⁄10
⁄4
8
⁄10
3

1
11⁄4
1 6 ⁄10

2
2 1⁄ 2
3

4
5

Approvals: Standard 248–14, UL Listed and CSA
Certified. MITI approved 1 – 5 Amps.

Note: For fuses with axial leads add “XE” extension to
the part number. Example 239.600XE

225/224 Series
2AG Fast-Acting fuse

Fast acting performance of the 312, 3AG fuses
in less than one-third the space. For protection of
electronic equipment and appliances.

Voltage Rating:
250V: 1⁄10 – 3 1⁄ 2 A. 125V: 4 – 10A
Dimensions:
2AG Fuse .177" x .57" (4.5 x 14.5mm)
Example part number (series & amperage): 224.500

Ampere Ratings:
1

3

1

1

⁄10
⁄8
1
⁄4

⁄8
⁄2
3
⁄4

1
11⁄2
2

2 1⁄ 2
3
3 1⁄2

4
5
6

7
8
10

Approvals: Standard 248–14, UL Listed and CSA
Certified. 224 series approved by MITI 1 – 5 Amps.

Note: For fuses with axial leads, request series number
224. Order 225 series without leads.

229/230 Series
2AG SLO-BLO® fuse

229 series 2AG fuses have time-delay of 313
series 3AG fuses in less than one-third the space.
They provide superior protection for inductive
loads such as motors, transformers, and solenoids.
Use whenever time-delay fuses are indicated.

Ampere Ratings:

Voltage Rating:
250V: 1⁄4 – 31⁄2 A; 125V: 4 – 7A.
Dimensions:
2AG Fuse .177" x .57" (4.5 x 14.5mm)
Example part number (series & amperage): 229.375

Approvals: Standard 248-14, UL Listed and
CSA Certified 1⁄4 – 3 1⁄2 Amps. UL Recognized under the
Components Program and CSA Recognized under the
Component Acceptance Program 4 – 7 Amps.

1

6

3

3

⁄4
⁄8
1
⁄2

⁄10
⁄4
1

11⁄ 2
2
2 1⁄ 4

2 1⁄ 2
3
3 1⁄2

4
5

6
7

Note: For fuses with axial leads, request series number
230. Order 229 series without leads.

58

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

Electronic Fuses
Subminiature Type
272/278 Series
Fast-Acting Microfuse

Fast acting Microfuses for protection of printed circuit
boards and similar equipment.
Voltage Rating: 125V AC
Example part number (series & amperage): 27201.5
Note: 278 series has 1" leads

.235"

.29"

.17"
.10"

Fast-Acting Microfuse

Similar to 272 and 278 series, except has transparent
cap for visual indication of fuse status.
Voltage Rating: 125V AC
Example part number (series & amperage): 273002
Note: 279 series has 1" leads
.25"

.35"

Fast-Acting Pico®II Fuse

1

1

1

⁄ 500
⁄ 200
1
⁄100
1
⁄ 64

1

⁄ 32
⁄ 20
1
⁄16
1
⁄10

4

⁄8
⁄10
1
⁄4
3
⁄10

3

⁄10
⁄2
6
⁄10
7
⁄10

2

⁄4
⁄10
1
11⁄ 2

1

8

2
3
4
5

Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program.
For data on 262 and 268 series High Reliability (Hi-Rel)
microfuses, request Electronic Catalog.

Ampere Ratings:
1

1

1

1

⁄ 500
⁄ 200
1
⁄100
1
⁄ 64

1

⁄ 32
⁄ 20
1
⁄16
1
⁄10

4

⁄8
⁄10
1
⁄4
3
⁄10

3

⁄10
⁄2
6
⁄10
7
⁄10

2

⁄4
⁄10
1
11⁄2

1

8

2
3
4
5

Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program.

.17"
.10"

251/252 Series

1

Midget & Electronic Fuses

273/279 Series

Ampere Ratings:

Subminiature fuse for soldered mounting on
printed circuit boards. Available on tape and reel
for automatic insertion.

Ampere Ratings:
3
⁄16
⁄8
1
2 1⁄2
4
10
1
1
⁄8
⁄2
1 ⁄2
3
5
12
3
1
⁄4
⁄4
2
3 1⁄ 2
7
15
Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program.
Order 252 series for radial leads. To order PICO II fuses
with ampere ratings color-coded, order 255 series for
axial leads and 256 for radial leads.
For data on 265 and 266 series High Reliability (Hi-Rel)
Picofuses, request Electronic Catalog. For information
on PICO II 250V fast-acting fuses, contact factory.
1

1

Voltage Rating: 125V: 1⁄ 16 – 10A; 32V: 12 – 15A.
Example part number (series & amperage): 251.125

1.47"

.28"

1.47"
.095"
DIA.

1A

LF

EPOXY COATING

473 Series
SLO-BLO® Pico®II Fuse

Subminiature time-delay fuse for soldered
mounting on printed circuit boards. Available on
tape and reel for automatic insertion. Request
bulletin PB-1027 for further information.

Ampere Ratings:

Voltage Rating: 125V AC
Example part number (series & amperage): 473005

Approvals: UL Recognized under the Components
Program and CSA Recognized under the Component
Acceptance Program. MITI approved 1 – 5 Amp.

1.47"

.28"

LF

3

⁄8
⁄2

1

3

⁄4
1

11⁄2
2

2 1⁄ 4
2 1⁄2

3
3 1⁄ 2

4
5

7

1.47"

1A

.095"
DIA.

EPOXY COATING

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

59

Midget & Electronic Fuses

Automotive Fuses
SFE and Blade Type
SFE Series
Fast-Acting Fuse

Low voltage fuse for automotive and electronic
applications.

Midget & Electronic Fuses

Voltage Rating: 32V AC/DC
Approvals: UL Listed under UL Standard #275.
Society of Automotive Engineers (SAE) J554.
Example part number (series & amperage): SFE006

ATO® /257 Series
Fast-Acting Fuse

The 257 series ATO fuse is a low voltage blade
type fuse for automotive and electronic applications. Designed, originated and patented by
Littelfuse, it has become the standard for OEM
circuit protection on foreign and domestic autos
and trucks. They are color-coded and readily identifiable and may be specified for a variety of low
voltage applications.

Voltage Rating: 32V AC/DC
Example part number (series & amperage): ATO015
Approvals: UL Listed. CSA Certified 3 – 30 A.

MIN/297 Series
®

MINI Fast-Acting Fuse

The MINI fuse is smaller than its predecessor,
the ATO fuse, which permits using more fuses
in the same amount of space. More fuses in the
same space satisfies the requirement that more
circuits be individually fused in newer automobiles.
Patented by Littelfuse.

Voltage Rating: 32V AC/DC
Example part number (series & amperage): MIN025
Approvals: UL Listed.
Note: For low-profile MINI® fuse, request 897 series

MAX/299 Series
MAXI™ SLO-BLO® Fuse

The patented MAXI Fuse is available in a higher
range of amperage ratings (20 – 80 amperes) than
the ATO or MINI fuses, and is physically larger
in size. It is color-coded for easy identification. A
typical MAXI Fuse application, in today’s more
sophisticated automobile circuits, is protection of
the wiring harness by replacing the fusible wire
or fusible link which is often a plain piece of small
wire.

Ampere Ratings/Dimensions:
Ampere Rating

Length

Diameter

4
6
71⁄ 2
9
14
20
30

5 8

14

⁄"
⁄"
78
⁄"
78
⁄"
11⁄16"
11⁄4"
17⁄ 16"

⁄"
⁄"
14
⁄"
14
⁄"
14
⁄"
14
⁄"
14
⁄"

3 4

14

Catalog No.

Amp. Rating

Volt. Rating

Color Code

ATO 001
ATO 002
ATO 003
ATO 004
ATO 005
ATO 07.5
ATO 010
ATO 015
ATO 020
ATO 025
ATO 030
ATO 040

1
2
3
4
5
7 1⁄ 2
10
15
20
25
30
40

32
32
32
32
32
32
32
32
32
32
32
32

Black
Grey
Violet
Pink
Tan
Brown
Red
Blue
Yellow
Natural
Green
Orange

Catalog No.

Amp. Rating

Volt. Rating

Color Code

MIN 002
MIN 003
MIN 004
MIN 005
MIN 07.5
MIN 010
MIN 015
MIN 020
MIN 025
MIN 030

2
3
4
5
71⁄ 2
10
15
20
25
30

32
32
32
32
32
32
32
32
32
32

Grey
Violet
Pink
Tan
Brown
Red
Blue
Yellow
Natural
Green

Catalog No.

Amp. Rating

Volt. Rating

Color Code

MAX 020
MAX 030
MAX 040
MAX 050
MAX 060
MAX 070
MAX 080

20
30
40
50
60
70
80

32
32
32
32
32
32
32

Yellow
Green
Orange
Red
Blue
Tan
Natural

Voltage Rating: 32V AC/DC
Example part number (series & amperage): MAX070
Approvals: UL Listed.

60

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Midget & Electronic Fuses

Automotive Fuses
Bolt-On Type

Specifications
Voltage Rating:
Interrupting Rating:

32V AC/DC
2000 A @ 32VDC
Amp. Rating

Volt. Rating

Color Code

MEG100
MEG125
MEG150
MEG175
MEG200
MEG225
MEG250

100
125
150
175
200
225
250

32
32
32
32
32
32
32

Yellow
Green
Orange
White
Blue
Tan
Pink

Midget & Electronic Fuses

Catalog No.

Example part number (series & amperage): MEG200

MEGA® SLO-BLO® Bolt-On Fuse

Recommended Fuse Holder

The MEGA Fuse is designed for the protection of high current
applications. Designed and patented by Littelfuse, it is ideal for battery
and alternator protection and other heavy gauge cable applications.

298900

Specifications
Voltage Rating:
Interrupting Rating:

MIDI® SLO-BLO® Bolt-On Fuse
The patented design of the Littelfuse MIDI fuse offers a bolt-on space
saving fuse with SLO-BLO characteristics for high current wiring
protection.

32V AC/DC
1000 A @ 32VDC

Catalog No.

Amp. Rating

Volt. Rating

Color Code

498030
498040
498050
498060
498070
498080
498100
498125
498150
498200

30
40
50
60
70
80
100
125
150
200

32
32
32
32
32
32
32
32
32
32

Pink
Green
Red
Yellow
Brown
White
Blue
Orange
Grey
Violet

Example part number (series & amperage): 498080

Recommended Fuse Holder
498900

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

61

Midget & Electronic Fuses

Automotive Fuses
Miscellaneous
JCASE® SLO-BLO® Fuse
The patented JCASE is a cartridge style fuse with female terminals. It
was designed to provide increased time-delay to handle in-rush currents
and low voltage drop to protect high current automotive circuits.

Specifications
Midget & Electronic Fuses

Voltage Rating:
Interrupting Rating:

32V AC/DC
1000 A @ 32VDC

Catalog No.

Amp. Rating

Volt. Rating

Color Code

JCAS20
JCAS30
JCAS40
JCAS50
JCAS60

20
30
40
50
60

32
32
32
32
32

Blue
Pink
Green
Red
Yellow

Example part number (series & amperage): JCAS60

Specifications
Voltage Rating:
Interrupting Rating:

32V AC/DC
2000 A @ 32VDC

Catalog No.

Amp. Rating

Volt. Rating

Wire Gauge

496060
496080
496100
496125
496150
496175
496200

60
80
100
125
150
175
200

32
32
32
32
32
32
32

10AWG
8AWG
8AWG
6AWG
4AWG
4AWG
4AWG

Example part number (series & amperage): 496060
Standard item:
1 foot cable on one side; 3 foot cable on the other side.

CablePro® Cable Protector Fuse
The CablePro Fuse is a high performance alternative for providing a
reliable, safe, and cost effective fusible link. It provides similar circuit
protection as the MEGA® fuse in a slim package that fits into tight
locations. The standard CablePro features 1 one foot wire lead and 1
three foot wire lead. Contact the factory for custom wire lead lengths.

62

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

64

R Rated Medium Voltage Fuses

65-68

E Rated Medium Voltage Fuses

69-73

E Rated Potential Transformer Fuses

74

Live Parts

75

www.littelfuse.com

Medium Voltage Fuses

Medium Voltage Fuses
2,400 - 38,000 VAC • Current-Limiting
Current-limiting “E” and “R” rated fuses
are equipped with a mechanical indicator
or striker pin that protrudes through the
fuse cap upon operation of the fuse. This
provides visual identification of a blown
fuse and can be used as a trigger for
external devices.

Note: Extension distance 1/2” min; extension
force 2lb. min

General Information

Medium Voltage Fuses

The terms “Medium Voltage” and “High Voltage” have been used
interchangeably by many people to describe fuses operating above 600
volts. Technically speaking, “medium voltage” fuses are those intended
for the voltage range from 2,400 to 38,000 VAC. “High voltage” fuses
are for circuits carrying voltages greater than 38,000 VAC.
“E” rated fuses are considered to be general purpose fuses and can be
used to protect against low and high values of fault current. “R” rated
fuses are designed for back-up protection. They must be used in series
with other devices such as motor overload relays in order to achieve
both overload and short-circuit protection.
Medium voltage fuses are not intended to provide overload protection in
the same sense as fuses rated 600 volts or less. Medium voltage fuse
current ratings do not have the same meanings as the ampere ratings of
low voltage fuses.
Littelfuse now offers a complete selection of “E” and “R” rated
medium voltage fuses for the protection of transformers, potential
transformers, feeders, and motor circuits. Single, double, and triple
barrel designs are available to cover a wide range of current, voltage,
and interrupting ratings. Conventional ferrule type, clip lock, and bolt-in
mounting configurations are now available for virtually any application.
Hermetically sealed fuses for use in hazardous environments are also
offered.

All medium voltage fuses are limited in their ability to interrupt low value
overcurrents, especially those between 100% and 200% of the fuse’s
continuous current rating. They are designed to carry their rated current
without exceeding the temperature rise permitted by NEMA and ANSI
standards.
Additional application data can be found in the Fuse Application section
of this catalog.

Contact the factory or your local Littelfuse representative for additional
fuse ratings or custom mounting configurations.
24 Hour Emergency Service is available. Call 847 824 1188.

Applications
Power Transformer Protection
Potential Transformer Protection
Motor Controller Back-up Protection
Fused Switches
Feeder Circuits

Bolt-in Mount Fuses

64

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

R Rated Medium Voltage Fuses
Current-Limiting

Features

Characteristics

“R” rated fuses provide required short-circuit protection for medium
voltage motors, motor controllers and associated circuitry. These
components have limited ability to absorb the energy of large shortcircuit currents. Medium voltage motor controllers contain overload
relays which provide both overload protection and locked rotor
protection to the motor. The controllers are also intended to interrupt
low value short-circuits within the capability of the motor controller. This
protects the medium voltage fuse from sustained overcurrents which
are less than their minimum interrupting rating.

Voltage Rating:
Current Range:

2,400 volts – 8,250 volts
2R – 36R

Options
• Hermitically sealed for use in hazardous locations
(add “S” suffix to part number)
• Bolt-in mounting configurations

NEMA Standards for “R” rated medium voltage power fuses require
they operate within 15-35 seconds when subjected to an rms current
100 times the “R” rating. For example, a fuse with a 2R rating will open
within 15 to 35 seconds on an applied current of 2 x 100 = 200 amperes.

Hookeye Feature*

130-4R-1C-5.5

Medium Voltage Fuses

*For hookeye attachment; add “W” suffix
to part number

Part Number System

Max Voltage (KV)
Style (C-Cartridge)
No. of Barrels
Rating (size)
Continuous Current
6.38"

3"DIA

Dim.A
Clip
Center

R

2.75 KV

Rated

9.75"

Dim.B

D

DD

DDD

Figure 1

Figure 2

Figure 3

Catalog
Number

Old
Catalog
Number

Size

70-2R-1C-2.75
100-3R-1C-2.75
130-4R-1C-2.75
150-5R-1C-2.75
170-6R-1C-2.75
200-9R-1C-2.75
230-12R-1C-2.75
390-18R-2C-2.75
450-24R-2C-2.75

LCK 2R
LCK 3R
LCK 4R
LCK 5R
LCK 6R
LCK 9R
LCK 12R
LCK 18R
LCK 24R

2R
3R
4R
5R
6R
9R
12R
18R
24R

Maximum
Dim. A
Continuous Current
(inches)
@ 40 deg C.
70
100
130
150
170
200
230
390
450

7"
7"
7"
7"
7"
7"
7"
7"
7"

Dim. B Min. Interrupting Max Interrupting Figure
(inches) Rating RMS Amps Rating RMS Asym Number
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"

170
250
340
390
500
760
1000
1500
1950

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

1
1
1
1
1
1
1
2
2

Add “w” suffix to part number for hookeye attachment.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

65

Medium Voltage Fuses

R Rated Medium Voltage Fuses
Current-Limiting
3"DIA

Dim.A
(Clip
Center)

5.5 KV

14”Clip Centers

5.5 KV

Medium Voltage Fuses

Rated

R

8.25 KV

Rated

Catalog
Number
70-2R-1C-5.5
100-3R-1C-5.5
130-4R-1C-5.5
150-5R-1C-5.5
170-6R-1C-5.5
200-9R-1C-5.5
230-12R-1C-5.5
390-18R-2C-5.5
450-24R-2C-5.5
480-26R-2C-5.5
550-30R-2C-5.5
600-32R-2C-5.5
650-36R-2C-5.5
550-30R-3C-5.5
600-32R-3C-5.5
650-36R-3C-5.5
70-2R-1C-5.5X
100-3R-1C-5.5X
130-4R-1C-5.5X
150-5R-1C-5.5X
170-6R-1C-5.5X
200-9R-1C-5.5X
230-12R-1C-5.5X
390-18R-2C-5.5X
450-24R-2C-5.5X
550-30R-2C-5.5X
Catalog
Number
70-2R-1C-8.25
100-3R-1C-8.25
130-4R-1C-8.25
150-5R-1C-8.25
170-6R-1C-8.25
200-9R-1C-8.25
230-12R-1C-8.25
390-18R-2C-8.25
450-24R-2C-8.25

Old
Catalog
Number
LCL 2R
LCL 3R
LCL 4R
LCL 5R
LCL 6R
LCL 9R
LCL 12R
LCL 18R
LCL 24R
—
—
—
—
—
—
LCL 36R
—
—
—
—
—
—
—
—
—
—

Old
Catalog
Number
—
—
—
—
—
—
—
—
—

9.75"

Figure 5

Figure 6

Dim.B

Figure 4

R

6.38"

2R
3R
4R
5R
6R
9R
12R
18R
24R
26R
30R
32R
36R
30R
32R
36R

Maximum
Continuous Current
@ 40 Degrees C°
70
100
130
150
170
200
230
390
450
480
550
600
650
550
600
650

2R
3R
4R
5R
6R
9R
12R
18R
24R
30R

70
100
130
150
170
200
230
390
450
550

Size

Size
2R
3R
4R
5R
6R
9R
12R
18R
24R

Maximum
Continuous Current
@ 40 Degrees C°
70
100
130
150
170
200
230
390
450

Dim. A
(inches)

Dim. B
(inches)

Min. Interrupting Max Interrupting
Figure
Rating RMS Amps Rating RMS (Asym) Number

12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"

15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"

170
250
340
390
500
760
1000
1500
1950
2100
2400
2600
2900
2400
2600
2900

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

4
4
4
4
4
4
4
5
5
5
5
5
5
6
6
6

14"
14"
14"
14"
14"
14"
14"
14"
14"
14”

17.875"
17.875"
17.875"
17.875"
17.875"
17.875"
17.875"
17.875"
17.875"
17.875”

170
250
340
390
500
760
1000
1500
1950
2400

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

4
4
4
4
4
4
4
5
5
5

Dim. A
(inches)

Dim. B
(inches)

12"
12"
12"
12"
12"
12"
12"
12"
12"

15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"

Min. Interrupting Max Interrupting
Figure
Rating RMS Amps Rating RMS (Asym) Number
190
225
330
440
500
740
955
1440
1910

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

4
4
4
4
4
4
4
5
5

Add “w” suffix to part number for hookeye attachment.

66

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

R Rated Medium Voltage Fuses
Current-Limiting
Littelfuse POWR-GARD™ medium voltage fuses are available in
several bolt-in mounting configurations. Contact factory for custom
configurations.

“B”
“BI”
“IB”

Bolt mount
Bolt-In mount
Inverted-Bolt mount

Refer to illustrations for mounting dimensions.

(2) .34" X .660 Slots
1.38" Apart

Medium Voltage Fuses

3" Dia.

Indicator

Indicator

Indicator

Dim.B

Indicator

3" Dia.

Dim.B

Dim.B

(2) .34" Holes
1.38" Apart

Dim.A

Dim.A

Figure 7

Figure 8

Figure 9

Bolt Mount “B”

2.75 KV

2.75 KV

Rated

Number

Old
Catalog
Number

70-2R-1B-2.75
00-3R-1B-2.75
30-4R-1B-2.75
150-5R-1B-2.75
170-6R-1B-2.75
200-9R-1B-2.75
230-12R-1B-2.75
390-18R-2B-2.75
450-24R-2B-2.75

—

Bolt Mount “B”

Catalog

70-2R-1IB-2.75
100-3R-1IB-2.75
130-4R-1IB-2.75
150-5R-1IB-2.75
170-6R-1IB-2.75
200-9R-1IB-2.75
230-12R-1IB-2.75
390-18R-2IB-2.75
450-24R-2IB-2.75

—

Inverted Bolt “IB”

R

—
—
—
—
—
—
—
—

—
—
—
—
—
—
—
—

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Figure 10

Inverted-Bolt “IB”

Size

Maximum
Dim. A
Continuous Current
(inches)
@ Degrees C°

Dim. B Min. Interrupting Max Interrupting
Figure
(inches) Rating RMS Amps Rating RMS (Asym) Number

2R
3R
4R
5R
6R
9R
12R
18R
24R

70
100
130
150
170
200
230
390
450

4.6"
4.6"
4.6"
4.6"
4.6"
4.6"
4.6"
7.4"
7.4"

13"
13"
13"
13"
13"
13"
13"
13"
13"

170
250
240
390
500
760
1000
1500
1950

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

7
7
7
7
7
7
7
8
8

2R
3R
4R
5R
6R
9R
12R
18R
24R

70
100
130
150
170
200
230
390
450

—
—
—
—
—
—
—
—
—

13"
13"
13"
13"
13"
13"
13"
13"
13"

170
250
340
390
500
760
1000
1500
1950

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

9
9
9
9
9
9
9
10
10

www.littelfuse.com

67

Medium Voltage Fuses

R Rated Medium Voltage Fuses
Current-Limiting
.44" X .91" Slots (1.53" c.t.c.)

3"Dia.

Indicator

Indicator

Dim.B

Dim.B

Bolt-In Mount “BI”

Dim.A

Dim.A

Front View
Dim.A

Size

Bolt In Mount “BI”

70-2R-1BI-5.5
100-3R-1BI-5.5
130-4R-1BI-5.5
150-5R-1BI-5.5
170-6R-1BI-5.5
200-9R-1BI-5.5
230-12R-1BI-5.5
390-18R-2BI-5.5
450-24R-2BI-5.5
480-26R-2BI-5.5
550-30R-2BI-5.5
600-32R-2BI-5.5
650-36R-2BI-5.5
550-30R-3BI-5.5
600-32R-3BI-5.5
650-36R-3BI-5.5
700-38R-3BI-5.5

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

2R
3R
4R
5R
6R
9R
12R
18R
24R
26R
30R
32R
36R
30R
32R
36R
38R

70
100
130
150
170
200
230
390
450
480
550
600
650
550
600
650
700

3.6”
3.6”
3.6”
3.6”
3.6”
3.6”
3.6”
7.6”
7.6”
7.6”
7.6”
7.6”
7.6”
—
—
—
—

18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"

170
250
340
390
500
760
1000
1500
1950
2200
2400
2650
2900
—
—
—
—

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

11
11
11
11
11
11
11
12
12
12
12
12
12
13
13
13
13

Bolt Mount “B”

70-2R-1B-5.5
100-3R-1B-5.5
130-4R-1B-5.5
150-5R-1B-5.5
170-6R-1B-5.5
200-9R-1B-5.5
230-12R-1B-5.5
390-18R-2B-5.5
450-24R-2B-5.5
550-30R-2B-5.5
600-32R-2B-5.5
650-36R-2B-5.5

—
—
—
—
—
—
—
—
—
—
—
—

2R
3R
4R
5R
6R
9R
12R
18R
24R
30R
32R
36R

70
100
130
150
170
200
230
390
450
550
600
650

4.6”
4.6”
4.6”
4.6”
4.6”
4.6”
4.6”
7.4”
7.4”
8.4”
8.4”
8.4”

18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"

170
250
340
390
500
760
1000
1500
1950
2400
2650
2900

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

7
7
7
7
7
7
7
8
8
8
8
8

Inverted Bolt “IB”

70-2R-1IB-5.5
100-3R-1IB-5.5
130-4R-1IB-5.5
150-5R-1IB-5.5
170-6R-1IB-5.5
200-9R-1IB-5.5
230-12R-1IB-5.5
390-18R-2IB-5.5
450-24R-2IB-5.5
550-30R-2IB-5.5
600-32R-2IB-5.5
650-36R-2IB-5.5

—
—
—
—
—
—
—
—
—
—
—
—

2R
3R
4R
5R
6R
9R
12R
18R
24R
30R
32R
36R

70
100
130
150
170
200
230
390
450
550
600
650

—
—
—
—
—
—
—
—
—
—
—
—

18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"
18"

170
250
340
390
500
760
1000
1500
1950
2400
2650
2900

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

9
9
9
9
9
9
9
10
10
10
10
10

70-2R-1BI-8.25
100-3R-1BI-8.25
130-4R-1BI-8.25
150-5R-1BI-8.25
170-6R-1BI-8.25
200-9R-1BI-8.25
230-12R-1BI-8.25
390-18R-2BI-8.25
450-24R-2BI-8.25

—
—
—
—
—
—
—
—
—

2R
3R
4R
5R
6R
9R
12R
18R
24R

70
100
130
150
170
200
230
390
450

3.6”
3.6”
3.6”
3.6”
3.6”
3.6”
3.6”
7.6”
7.6”

18"
18"
18"
18"
18"
18"
18"
18"
18"

190
225
330
400
500
740
955
1440
1910

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

11
11
11
11
11
11
11
12
12

Rated

Number

5.5 KV

5.5 KV

5.5 KV

Catalog

Maximum
Dim. A
Continuous Current
(inches)
@ 40˚ C.

Figure 13

Old
Catalog
Number

R

8.25 KV
68

Figure 12

Bolt-In Mount “BI”

Medium Voltage Fuses

Figure 11

Dim. B Min. Interrupting Max Interrupting
Figure
(inches) Rating RMS Amps Rating RMS (Asym) Number

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

E Rated Medium Voltage Fuses
Current-Limiting

Characteristics

“E” Rated fuses have time current characteristics designed to
provide current-limiting protection for power transformers, potential
transformers, power centers, feeder centers, and unit sub stations.
When properly applied, they can protect against high and low fault
currents.

Voltage Rating: 2,400 volts – 38,000 volts
Current Range: 10E – 600E

Options
NEMA Standards for “E” rated medium voltage fuses require that
fuses rated 100E or less open within 300 seconds (5 minutes) when
subjected to an RMS value of 200-240% of the fuse continuous current
rating; and fuses with an “E” rating larger than 100E must open within
600 seconds (10 minutes) when subjected to an RMS current of 220240% of the fuse’s continuous current rating. These values establish
one point on the time-current curve.

• Hermetically sealed for use in hazardous locations
(add “S” suffix to part number)
• Clip-lock (CL) and bolt-in styles available.

Application Note:
Since these fuses are used for the protection of general purpose
circuits which may contain transformers, motors, and other equipment
producing in-rush and/or overload currents, fuses should generally be
rated at 140% of the normal full load current, and circuits should be
analyzed to ensure that system load currents will not exceed the current
rating of the fuse.

6.38"

Dim.A
(Clip
Center)

Dim.B

Figure 14

E

2.75 Max. KV

Rated

9.75"

Medium Voltage Fuses

3"DIA

Figure 15

Figure 16

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure Number

10E-1C-2.75
15E-1C-2.75
20E-1C-2.75
25E-1C-2.75
30E-1C-2.75
40E-1C-2.75
50E-1C-2.75
65E-1C-2.75
80E-1C-2.75
100E-1C-2.75
125E-1C-2.75
150E-1C-2.75
200E-1C-2.75
125E-2C-2.75
150E-2C-2.75
175E-2C-2.75
200E-2C-2.75
225E-2C-2.75
250E-2C-2.75
300E-2C-2.75
350E-2C-2.75
400E-2C-2.75
450E-2C-2.75

LCX 10E
—
—
—
LCX 30E
LCX 40E
LCX 50E
LCX 65E
LCX 80E
LCX 100E
—
—
—
LCX 125E
LCX 150E
LCX 175E
LCX 200E
—
LCX 250E
LCX 300E
—
LCX 400E
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
200E
125E
150E
175E
200E
225E
250E
300E
350E
400E
450E

7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"
7"

10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"
10.875"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

14
14
14
14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
15
15
15
15
15

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

69

Medium Voltage Fuses

E Rated Medium Voltage Fuses
Current-Limiting
Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Diagram

5.5 Max. KV

10E-1C-5.5
15E-1C-5.5
20E-1C-5.5
25E-1C-5.5
30E-1C-5.5
40E-1C-5.5
50E-1C-5.5
65E-1C-5.5
80E-1C-5.5
100E-1C-5.5
125E-1C-5.5
150E-1C-5.5
175E-1C-5.5
200E-1C-5.5
125E-2C-5.5
150E-2C-5.5
175E-2C-5.5
200E-2C-5.5
250E-2C-5.5
300E-2C-5.5
350E-2C-5.5
400E-2C-5.5
450E-2C-5.5
500E-3C-5.5
550E-3C-5.5
600E-3C-5.5

—
—
—
—
LCY 30E
LCY 40E
LCY 50E
LCY 60E
LCY 80E
LCY 100E
LCY 125E
LCY 150E
LCY 175E
LCY 200E
—
—
—
—
LCY 250E
LCY 300E
LCY 350E
LCY 400E
LCY 450E
—
—
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
175E
200E
125E
150E
175E
200E
250E
300E
350E
400E
450E
500E
550E
600E

12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"

15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"
15.875"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

14
14
14
14
14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
15
15
15
15
16
16
16

5.5 Max. KV

E

5NLE-10E
5NLE-15E
5NLE-20E
5NLE-25E
5NLE-30E
5NLE-40E
5NLE-50E
5NLE-65E
5NLE-80E
5NLE-100E
5NLE-125E
5NLE-150E
5NLE-175E
5NLE-200E
5NLE2-225E
5NLE2-250E
5NLE2-300E
5NLE2-350E
5NLE2-400E
5NLE2-450E

—
—
—
—
LCU 30E
LCU 40E
LCU 50E
LCU 65E
LCU 80E
LCU 100E
LCU 125E
LCU 150E
LCU 175E
LCU 200E
—
LCU 250E
LCU 300E
LCU 350E
LCU 400E
LCU 450E

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
175E
200E
225E
250E
300E
350E
400E
450E

14”
14”
14”
14”
14”
14”
14”
14”
14”
14”
14“
14”
14”
14”
14”
14”
14”
14”
14”
14”

17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

14
14
14
14
14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
15

Medium Voltage Fuses

Rated

70

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

E Rated Medium Voltage Fuses
Current-Limiting
Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Diagram

8.25 Max. KV

10E-1C-8.25
15E-1C-8.25
20E-1C-8.25
25E-1C-8.25
30E-1C-8.25
40E-1C-8.25
50E-1C-8.25
65E-1C-8.25
80E-1C-8.25
100E-1C-8.25
125E-1C-8.25
150E-1C-8.25
125E-2C-8.25
150E-2C-8.25
200E-2C-8.25
250E-2C-8.25
300E-2C-8.25
350E-3C-8.25
400E-3C-8.25

—
—
—
—
LDZ 30E
LDZ 40E
LDZ 50E
LDZ 65E
LDZ 80E
LDZ 100E
LDZ 125E
LDZ 150E
LDZ 125E
LDZ 150E
LDZ 200E
LDZ 250E
LDZ 300E
LDZ 350Z
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
125E
150E
200E
250E
300E
350E
400E

12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"
12"

15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"
15 7⁄ 8"

80,000,
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

14
14
14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
16
16

8NLE-10E
8NLE-15E
8NLE-20E
8NLE-25E
8NLE-30E
8NLE-40E
8NLE-50E
8NLE-65E
8NLE-80E
8NLE-100E
8NLE2-100E
8NLE2-125E
8NLE2-150E
8NLE2-200E
8NLE2-250E

—
—
—
—
LCZ 30E
LCZ 40E
LCZ 50E
LCZ 65E
LCZ 80E
LCZ 100E
LCZ 100E
LCZ 125E
LCZ 150E
LCZ 200E
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
100E
125E
150E
200E
250E

14"
14"
14"
14"
14"
14"
14"
14"
14"
14"
14"
14"
14"
14"
14"

17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"
17 7⁄8"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

14
14
14
14
14
14
14
14
14
14
14
15
15
15
15

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

10E-1C-15.5
15E-1C-15.5
20E-1C-15.5
25E-1C-15.5
30E-1C-15.5
40E-1C-15.5
50E-1C-15.5
65E-1C-15.5
80E-1C-15.5
100E-1C-15.5
65E-2C-15.5
80E-2C-15.5
100E-2C-15.5
125E-2C-15.5
150E-2C-15.5
175E-2C-15.5
200E-2C-15.5
200E-3C-15.5
250E-3C-15.5
300E-3C-15.5

LDN 10E
LDN 15E
LDN 20E
LDN 25E
LDN 30E
LDN 40E
LDN 50E
LDN 65E
LDN 80E
LDN 100E
—
—
—
—
LDN 150E
LDN 175E
—
—
—
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
65E
80E
100E
125E
150E
175E
200E
200E
250E
300E

15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"
15"

18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"
18.875"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
15
15
16
16
16

Rated

E

15.5 Max. KV

Rated

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Medium Voltage Fuses

Catalog Number

8.25 Max. KV

E

71

Medium Voltage Fuses

E Rated Medium Voltage Fuses
Current-Limiting
Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

15.5
Max. KV

15GSE-65E
15GSE-80E
15GSE-100E
15GSE2-125E
15GSE2-150E
15GSE2-175E
15GSE2-200E

—
—
—
—
—
—
—

65E
80E
100E
125E
150E
175E
200E

18"
18"
18"
18"
18"
18"
18"

21 7⁄ 8"
21 7⁄ 8"
21 7⁄ 8"
21 7⁄ 8"
21 7⁄ 8"
21 7⁄ 8"
21 7⁄ 8"

60,000
60,000
60,000
60,000
60,000
60,000
60,000

14
14
14
15
15
15
15

15.5 Max. KV

E

15NLE-10E
15NLE-15E
15NLE-20E
15NLE-25E
15NLE-30E
15NLE-40E
15NLE-50E
15NLE-65E
15NLE-80E
15NLE-100E
15NLE2-80E
15NLE2-100E
15NLE2-125E
15NLE2-150E
15NLE2-175E
15NLE2-200E
15NLE3-150E
15NLE3-175E
15NLE3-250E
15NLE3-300E

—
—
—
—
LCN 30E
LCN 40E
LCN 50E
LCN 65E
LCN 80ES
LCN 100ES
LCN 80E
LCN 100E
LCN 125X
LCN 150E
—
LCN 200ED
—
—
—
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
80E
100E
125E
150E
175E
200E
150E
175E
250E
300E

20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"
20"

23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"
23 7⁄ 8"

60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000

14
14
14
14
14
14
14
14
14
14
15
15
15
15
15
15
16
16
16
16

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

15E-1C-25.8
20E-1C-25.8
25E-1C-25.8
30E-1C-25.8
40E-1C-25.8
50E-1C-25.8
65E-2C-25.8
80E-2C-25.8
100E-2C-25.8

—
—
—
—
—
—
—
—
—

15E
20E
25E
30E
40E
50E
65E
80E
100E

21"
21"
21"
21"
21"
21"
21"
21"
21"

24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"
24 5 ⁄ 8"

40,000
40,000
40,000
40,000
40,000
40,000
40,000
40,000
40,000

14
14
14
14
14
14
14
15
15

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

3E-1C-38.0
7E-1C-38.0
10E-1C-38.0
15E-1C-38.0
20E-1C-38.0
25E-1C-38.0
30E-1C-38.0
40E-1C-38.0
50E-2C-38.0
65E-2C-38.0
80E-2C-38.0

—
—
—
—
—
—
—
—
—
—
—

3E
7E
10E
15E
20E
25E
30E
40E
50E
65E
80E

27"
27"
27"
27"
27"
27"
27"
27"
27"
27"
27"

30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"
30 5 ⁄ 8"

20,000
20,000
20,000
20,000
20,000
20,000
20,000
20,000
20,000
20,000
20,000

14
14
14
14
14
14
14
14
15
15
15

Medium Voltage Fuses

Rated

E
25.8 Max. KV

Rated

E

38 Max. KV

Rated

72

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

E Rated Medium Voltage Fuses
Current-Limiting

4.75

A B

The clip lock type designs ensures a positive contact between the fuse
and the connection cam. The fuse’s clip lock tab slides in between the
clip casting and the cam to prevent the fuse from slipping or blowing out
of the holder. This positive contact improves heat dissipation and allows
fuses to run cooler.

Clip Lock

E

Clip Lock

8.25 Max. KV

Rated

E

Clip Lock

15.5 Max. KV

Rated

.25

3.0
1.25

Figure 17

Figure 18

Figure 19

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

10E-1CL-5.5
15E-1CL-5.5
20E-1C-5.5
25E-1CL-5.5
30E-1CL-5.5
40E-1CL-5.5
50E-1CL-5.5
65E-1CL-5.5
80E-1CL-5.5
100E-1CL-5.5
125E-1CL-5.5
150E-1CL-5.5
225E-2CL-5.5
250E-2CL-5.5
300E-2CL-5.5
350E-2CL-5.5
400E-2CL-5.5
450E-2CL-5.5
500E-3CL-5.5
550E-3CL-5.5
600E-3CL-5.5

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
225E
250E
300E
350E
400E
450E
500E
550E
600E

16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
16.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"

15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
15.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

17
17
17
17
17
17
17
17
17
17
17
17
18
18
18
18
18
18
19
19
19

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

10E-1CL-8.25
15E-1CL-8.25
20E-1C-8.25
25E-1CL-8.25
30E-1CL-8.25
40E-1CL-8.25
50E-1CL-8.25
65E-1CL-8.25
80E-1CL-8.25
100E-1CL-8.25
125E-2CL-8.25
150E-2CL-8.25
175E-2CL-8.25
200E-2CL-8.25
225E-2CL-8.25
250E-2CL-8.25
300E-2CL-8.25
350E-3CL-8.25

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125E
150E
175E
200E
225E
250E
300E
350E

17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"
17.38"

16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"
16.13"

80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000
80,000

17
17
17
17
17
17
17
17
17
17
18
18
18
18
18
18
18
19

Catalog Number

Old Catalog Number

Size

Dim. A (inches)

Dim. B (inches)

Max Interrupting
Rating RMS (Asym)

Figure
Number

10E-1CL-15.5
15E-1CL-15.5
20E-1CL-15.5
25E-1CL-15.5
30E-1CL-15.5
40E-1CL-15.5
50E-1CL-15.5
65E-1CL-15.5
80E-1CL-15.5
100E-1CL-15.5
125E-2CL-15.5
150E-3CL-15.5
175E-3CL-15.5
200E-3CL-15.5
225E-3CL-15.5
250E-3CL-15.5
300E-3CL-15.5

—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—

10E
15E
20E
25E
30E
40E
50E
65E
80E
100E
125
150E
175E
200E
225E
250E
300E

19.8"
19.8"
19.8"
19.8"
19.8"
19.8"
19.8"
22.81"
22.81"
22.81"
22.81"
22.81"
22.81"
22.81"
22.81"
22.81"
22.81"

18.1"
18.1"
18.1"
18.1"
18.1"
18.1"
18.1"
21.13"
21.13"
21.13"
19.1"
19.1"
19.1"
19.1"
19.1"
19.1"
19.1"

60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000
60,000

17
17
17
17
17
17
17
17
17
17
18
19
19
19
19
19
19

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Medium Voltage Fuses

5.5 Max. KV

Rated

11.56

1.25

Clip Lock Design

E

7.94

73

Medium Voltage Fuses

E Rated Potential Transformer Fuses
Current-Limiting
Potential Transformer (PT) fuses are current-limiting fuses with high
interrupting ratings designed for the protection of potential transformers.

Characteristics
Voltage Rating:
Current Range:

Application Note:

600VAC – 25,500 VAC
1/2E – 10E

When applying fuses for the protection of transformers, the magnetizing
current in-rush must be considered. The characteristics of the in-rush,
which can be matched with a fuse time-current curve, should be
available from the transformer manufacturer.

B

A

Catalog Number

Old Catalog Number

Size

Length Dim. A (inches)

Diameter Dim. B (inches)

Max Interrupting
Rating RMS (Sym)

600
Volt

3E-4PT-6
5E-4PT-6
7E-4PT-6
10E-4PT-6

—
—
—
—

3E
5E
7E
10E

4.6”
4.6”
4.6”
4.6”

0.8125”
0.8125”
0.8125”
0.8125”

37,500
37,500
37,500
37,500

2.75
Max.
kV

500E-4PT-2.4
1E-4PT-2.4
2E-4PT-2.4

—
LCD 1E-4
LCD 2E-4

1/2E
1E
2E

4.6”
4.6”
4.6”

0.8125”
0.8125”
0.8125”

37,000
37,000
37,000

2.75
Max.KV

1E-6PT-2.75
2E-6PT-2.75
3E-6PT-2.75
1E-8PT-2.75
2E-8PT-2.75
3E-8PT-2.75

—
—
—
—
—
—

1E
2E
3E
1E
2E
3E

7.4”
7.4”
7.4”
9.5”
9.5”
9.5”

1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”

37,500
37,500
37,500
37,000
37,000
37,000

1E-5PT-4.8

LCE 1E-4

1E

5.6”

0.8125”

50,000

2E-5PT-4.8

LCE 2E-4

2E

5.6”

0.8125”

50,000

5.5
Max. kV

1/2E-6PT-5.5
1E-6PT-5.5
2E-6PT-5.5
3E-6PT-5.5
5E-6PT-5.5
1/2E-8PT-5.5
1E-8PT-5.5
2E-8PT-5.5
3E-8PT-5.5
5E-8PT-5.5
10E-8PT-5.5

—
—
—
—
—
LCQ .5E
LCQ 1E
LCQ 2E
LCQ 3E
LCQ 5E
LCQ 10E

1/2E
1E
2E
3E
5E
1/2E
1E
2E
3E
5E
10E

7.4”
7.4”
7.4”
7.4”
7.4”
9.5”
9.5”
9.5”
9.5”
9.5”
9.5”

1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”

50,000
50,000
50,000
50,000
50,000
50,000
50,000
50,000
50,000
50,000
50,000

8.25
Max.
kV

1/2E-8PT-8.25
1E-8PT-8.25
2E-8PT-8.25
3E-8PT-8.25

—
—
—
—

1/2E
1E
2E
3

9.5”
9.5”
9.5”
9.5”

1.5625”
1.5625”
1.5625”
1.5625”

50,000
50,000
50,000
50,000

15.5
Max. kV

E

1/2E-11PT-15.5
1E-11PT-15.5
2E-11PT-15.5
3E-11PT-15.5
3E-16PT-15.5
5E-16PT-15.5

LCT .5E
LCT 1E
LCT 2E
LCT 3E
—
—

1/2E
1E
2E
3E
3E
5E

12.8”
12.8”
12.8”
12.8”
17.5”
17.5”

1.5625”
1.5625”
1.5625”
1.5625”
1.5625”
1.5625”

35,000
35,000
35,000
35,000
35,000
35,000

1/2E-16PT-25.5

LCJ 1E-4

1/2E

17.5”

1.5625”

43,500

1E-16PT-25.5

LCJ 2E-4

1E

17.5”

1.5625”

43,500

25.8
Max.
kV

4.8
Max.
kV

Medium Voltage Fuses

Rated

74

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Medium Voltage Fuses

Live Parts

Live parts are available for mounting “E”, “R”, and “PT” single, double, and triple barrel fuses.
Mounting clips are available for ferrule type and clip lock style fuses. All clips are sold in pairs.
Contact factory for additional live parts.

Part Number: 700-300*

System Number: 0700156.Z

System Number: 0700300.Z

For use with 1- 9 /16" to 1- 5/ 8” (1.625”) diameter PT fuses.

For use with 3" diameter fuses.

Medium Voltage Fuses

Part Number: 700-156*

2.00

3.74

2.85

Part Number: 700-500*

Part Number: 700-530*

.08

System Number: 0700500.Z

System Number: 0700530.Z

For use with all 13/16" (.8125”)
diameter PT fuses.

For use with all 3" diameter fuses.
.31
.71
.30

.78

.038" HOLES
.08

1.50
1.15

4.50

.05

3.08
4.16

.78

.63

Part Number: 700-520-CL*

Mounting Details for Clip Lock

System Number: 0700520.ZXCL
Clip Lock Design (For CL-14)
3.63

TRIPLE BARREL

3.63

DOUBLE BARREL

Bottom Lever In
Closed Position

SINGLE BARREL
4.85
1.75

Blown Fuse
Indicator

* One Pair. Dimensions for reference only.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

1.00
2.00
4.9
TOP
VIEW

3.75 2.00
Top Lever in
Open Position

www.littelfuse.com

A
2.00

.56 Dia. (2) Holes
For Mounting
Cable/Bus

.44 DIA. (2) HOLES

75

Telecom Products

Telecom Products

L17T Series Telecommunications Power Fuse

77

TLN Series Telecommunications Power Fuse

78

TLS Series Telecommunications Power Fuse

79

Alarm Indicating Fuses

80

LTFD 101 Series Telecommunications Disconnect Switch

81

LTFD Series Telecommunications Disconnect Switch

82

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Telecom Products

L17T Series Telecommunications Power Fuse
170 VDC • Current-Limiting • 70 – 1200 Amperes
Specifically designed for short-circuit protection of telecommunications
circuits, the Littelfuse L17T series fuses provide reliable protection of
sensitive DC power distribution systems. Constructed with silver plated
elements for low I2t and peak let-through, these advanced fuses virtually
eliminate equipment damage due to surges and spikes. The L17T series
fuse unique element geometry also provides cooler running temperatures,
helping to minimize heat within enclosures.

Ordering Information & Cross Reference

G

A
B
C
D

Ampere Rating

L17T 70
L17T 90
L17T 100
L17T 125
L17T 150
L17T 175
L17T 200
L17T 225
L17T 250
L17T 300
L17T 350
L17T 400
L17T 450
L17T 500
L17T 600
L17T 800
L17T 900
L17T 1000
L17T 1100
L17T 1200

70
90
100
125
150
175
200
225
250
300
350
400
450
500
600
800
900
1000
1100
1200

Ampere
Rating

E

Dimensions in Inches (mm in parentheses)
B
C
D
E
F
G
78
5 16
1 7⁄ 8
2 3 ⁄16
2 21 ⁄ 32
1
⁄
⁄
(47.6) (55.6) (67.5) (25.4) (22.2)
(7.9)
13 32
1 15 ⁄16
2 9 ⁄16
3 1⁄ 2
11⁄ 2
1
⁄
(49.2) (65.1) (88.9) (38.1) (25.4) (10.3)
4 1⁄16
11⁄ 2
—
—
—
—
(103.1)
(38.1)

Contact Littelfuse for characteristic curves.

Specifications

Ampere Ratings
170 VDC
100,000 amperes
70 – 1200 amperes
UL Recognized under the Components Program
(File No: E71611)
CSA Recognized under the Component Acceptance
Program (File No: LR29862)

Recommended Fuse Blocks
LTFD 6001 and LTFD 1200 series
Refer to the LTFD series in this catalog section for additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Competitor B
Part Number
TGL-BA
TGL-BC
TGL-BD
TGL-BE
TGL-BF
TGL-BG
TGL-BH
TGL-BK
TGL-BL
TGL-CN
TGL-CO
TGL-CR
TGL-CU
TGL-CV
TGL-CZ
TGL-CZH
–
–
–
–

H
A
1 5 ⁄ 32
70 – 250
(29.4)
11⁄ 4
300 – 800
(31.8)
1 11 ⁄ 32
1000–1200
(34.0)

Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

Competitor A
Part Number
TPL-BA
TPL-BC
TPL-BD
TPL-BE
TPL-BF
TPL-BG
TPL-BH
TPL-BK
TPL-BL
TPL-CN
TPL-CO
TPL-CR
TPL-CU
TPL-CV
TPL-CZ
TPL-CZH
–
–
–
–

Telecom Products

F

Catalog Number

70
80
90

100
125
150

175
200
225

250
300
350

400
450
500

600
800
900

H
⁄
(4.8)
14
⁄
(6.35)
14
⁄
(6.35)
3 16

1000
1100
1200

Example part number (series & amperage): L17T 200

Features
• Low I2t
• Extremely current-limiting
• Low operating temperature
• 170 VDC rating

www.littelfuse.com

77

Telecom Products

TLN Series Telecommunications Power Fuse
170 VDC • Current-Limiting • 1 – 600 Amperes

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

170 VDC
100,000 amperes
1 – 600 amperes
UL Recognized under the components program
(File No: E71611)

Ampere Ratings
1
3
5
6
10

15
20
25
30
35

40
45
50
60
70

80
90
100
110
125

150
175
200
225
250

300
350
400
450
500

600

Example part number (series & amperage): TLN450

Recommended Fuse Blocks

Telecom Products

LR250 Series
Refer to the Blocks & Holders section of this catalog for additional information.

Features
• 170 VDC
• Fast acting and current-limiting
• 1 to 600 amperes
• Dimensionally similar to 250V Class R fuses
The TLN Series fuses are specifically designed for the protection of
telecommunications DC power distribution circuits.

Replaces competitors’ TPN and TGN Series.

Dimensions in Inches (mm in parentheses)

Ampere Rating

A

B

C

D

E

F

G

H

J

K

⁄ (9.5)
⁄ (15.9)

—
—

—
—

—
—

Figure 1
1 – 30
35 – 60

12

12

⁄ (12.7)
⁄ (15.9)

9 16

5 64

3 4

58

13 16

3 32

11 ⁄16 (27.0)
115 ⁄ 32 (37.3)
115 ⁄16 (49.2)
2 3 ⁄8 (60.3)

11 ⁄16
119 ⁄ 32
2 3 ⁄ 32
2 19 ⁄ 32

⁄ (12.7)
⁄ (19.1)

2 (50.8)
3 (76.2)

⁄ (14.3)
⁄ (20.6)

⁄
⁄

(2.0)
(2.4)

18

(3.2)
(4.8)
(6.4)
(6.4)

5 32

⁄
⁄

3 16

(4.0)
(4.8)

3 8
5 8

Figure 2
70 – 100
110 – 200
225 – 400
450 – 600

5 7⁄ 8 (149.2)
7 1⁄8 (181.0)
8 5 ⁄8 (219.1)
10 3 ⁄ 8 (263.5)

1 (25.4)
11⁄ 2 (38.1)
2 (50.8)
2 1⁄2 (63.5)

(27.0)
(40.5)
(53.2)
(65.9)

⁄
⁄
14
⁄
14
⁄

3 16

3 4
⁄ (19.1)
11⁄ 8 (28.6)
15 ⁄ 8 (41.3)
2 (50.8)

A
F
G

14

⁄
⁄
5 8
⁄
3 4
⁄

7 16

(6.4)
(11.1)
(15.9)
(19.1)

9 32

⁄
⁄
13 32
⁄
17 32
⁄

(7.1)
(7.1)
(10.3)
(13.5)

F

D

9 32

12

⁄ (12.7)
⁄ (17.5)
15 16
⁄ (23.8)
11⁄ 8 (28.6)

11 16

A

K

C

D

B

11⁄ 4 (31.6)
1 27⁄ 32 (46.8)
2 11 ⁄ 32 (59.5)
2 27⁄ 32 (72.2)

B
H

E

C

J

FIG. 2

FIG. 1

78

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Telecom Products

TLS Series Telecommunications Power Fuse
170 VDC • Current-Limiting • 1 – 125 Amperes

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

170 VDC
100,000 amperes
1 – 125 amperes
UL Recognized under the components program
(File No: E71611)
Caps: Silver-plated brass
Glass melamine

Construction:
Body:

Ampere Ratings
1
2
3
5

6
10
15
20

25
30
35
40

50
60
70
80

90
100
110
125

Example part number (series & amperage): TLS050
Note: To order leaded versions of TLS fuses, add suffix V, L, LB, or LS to part
number.
Telecom Products

Recommended Fuse Blocks
Littelfuse TLS Series fuses are designed specifically for the protection
of telecommunications equipment. TLS fuses have been engineered to
operate up to 170 VDC to provide current-limiting short-circuit protection
for cables and components found in the DC power distribution circuits
of telecommunications systems. The compact design and multiple
mounting configurations of the TLS series allow it to be used in a variety
of applications.

Features

LTFD series disconnect switches
LT30060 for TLS series cartridge style fuse
Contact factory for more information.

Contact Littelfuse for characteristic curves. Dimensions for reference only. Replaces competitors’ TPS and TGS Series.

• 170 VDC
• Current-limiting
• 1 to 125 amperes
• Multiple mounting configurations
• RoHS Compliant

TLS

TLS-V

TLS-L

TLS-LB

TLS-LS

Cartridge

Vertical Mount

Leaded

Bolt-In

Solder

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

79

Telecom Products

Telecommunications Power Fuses
Alarm Indicating Fuses

Specifications
Voltage Rating:
Interrupting Rating:

125 VAC, 300 VDC
1,000 amperes @ 125 VAC
1,000 amperes @ 300 VDC

Ampere Ratings
100mA
150mA
180mA

200mA
250mA
350mA

500mA
750mA
1.33

2
3
3.5

5
8
10

Ordering Information
10 Minute Rating

70 Series Alarm Indicating Fuses
Telecom Products

Catalog Number System Number

100mA
150mA
180mA
200mA
250mA
250mA
350mA
500mA
750mA
1.33A
2A
3A
3.5A
5A
8A
10A

The 70 Series alarm indicating fuses are designed for use in
telecommunications equipment. A color coded tip provides visual
identification of the ampere rating and the fuse status.

Features
• Color coded tip
• Rated 125 VAC, 300 VDC

70P
70R
70E
70X
70F
70K
70S
70G
70H
70A
70B
70C
70J
70D
70M
70N

70P00000Z
70R00000Z
70E00000Z
70X00000Z
70F00000Z
70K00000Z
70S00000Z
70G00000Z
70H00000Z
70A00000Z
70B00000Z
70C00000Z
70J00000Z
70D00000Z
70M00000Z
70N00000Z

Color Code
Grey/White
Red/White
Yellow
Black
Violet
Violet/White
Gray
Red
Brown
White
Orange
Blue
Black/White
Green/Black
Tan/White
Yellow/Purple

Specifications
Voltage Rating:
Approvals:

125V AC, DC
UL Recognized under the Components Program and
CSA Recognized under the Component Acceptance
Program.

Ampere Ratings
18

⁄100
⁄5
1
⁄4
1

3

⁄8
⁄2
65
⁄100
1

3

⁄4
1
1 1⁄ 3

11⁄2
2
2 1⁄2

3
3 1⁄ 2
4

5
7 1⁄ 2
10

12
15
20

Example part number (series & amperage): 481005

Recommended Fuse Blocks
481 Series Alarm Indicating Fuses
For telecommunications equipment and similar applications. Color coded
indicator flags indicate ampere rating. Body is constructed of black
polyphenylene sulfide with UL 94V0 flammability rating, contacts are of
bright alloy-plated beryllium copper. Available with or without protective lens.

80

482 Series
Available 1-20 pole with PCB or panel mounting
To order with protective lens add suffix XL
NOTE: For 481 Dummy fuse order 481000.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Telecom Products

LTFD 101 Series Telecommunications Disconnect Switch
80 VDC • 1 – 125 Amperes
Littelfuse compact LTFD 101 fuseholders for TLS fuses are designed for
quick installation into telecom equipment panels. Their modular design
fits into spaces originally designed for circuit breakers and they can
be front panel mounted or rear mounted using bullet connectors. The
innovative new pull-out design eliminates the need for tools to replace
fuses and includes an alarm signaling circuit to identify the blown fuse.

Features
• Extremely compact
• Quick mounting
• Replaces circuit breakers
• Includes alarm signaling circuit

CL

6-32 INSERT

3.75"
2.00"

Telecom Products

0.75"

0.305" Dia.
Bullet Terminal

0.85"

LOAD
Alarm pin
0.02" x 0.11"
position optional

2.50"
2.062"

1.940"

LINE

Dimensions for reference only. For additional options and dimensions, contact the factory.

Specifications
Voltage Rating:
Ampere Range:
Approvals:

Ordering Information
80 VDC
1 – 125 A
UL Recognized (File No. E122874)

Recommended Fuses

Catalog Number

System Number

Terminal Type

LTFD101-1
LTFD101-2
LTFD101-3
LTFD101-4

LTFD0101ZX1
LTFD0101ZX2
LTFD0101ZX3
LTFD0101ZX4

Bullet
Screw
Stud
Clip

Littelfuse TLS Series fuses
Littelfuse 481 Series Alarm fuses

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

81

Telecom Products

LTFD Series Telecommunications Disconnect Switch
145 VDC, 60 VDC • 70 – 1200 Amperes

Features
• Innovative pullout design of the 1200A switch eliminates the need for
tools to replace the fuse
• Thermoplastic housing material
• Alarm signaling circuit

Specifications
Voltage Rating:

145 VDC for 70 – 600 amperes
60 VDC for 800 – 1200 amperes
70 – 1200 amperes
UL Recognized (E122674)

Ampere Range:
Approvals:

Recommended fuses
L17T Series fuses

Ordering Information

Telecom Products

Catalog Number
Littelfuse compact LTFD Series holders are designed for use as a
combination fuseholder and disconnect switch for telecommunications
equipment. The rugged unit utilizes a pull-out fuse carrier to safely
disconnect power and provide easy fuse replacement.

82

LTFD6001-00
LTFD6001-01
LTFD1200-01
LTFD1200-01A

Stud Size (A)
3 4

⁄ – 16 x 3.5 in.
⁄ – 14 x 3.5 in.
1.12 – 12 x 4 in
1.12 – 12 x 4 in

78

LTFD 6001 Series

LTFD 1200A

(70–800 Amperes)

(900–1200 Amperes)

www.littelfuse.com

Amperes
70 – 600
70 – 800
900 – 1200
900 – 1200

Contact Nut Max.
Torque
100 feet-pound
120 feet-pound
120 feet-pound
120 feet-pound

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Semiconductor Fuses

84

Traditional Semiconductor Fuses

85-87

LA15QS Semiconductor Fuses

88-89

LA30QS Semiconductor Fuses

90-91

LA50QS Semiconductor Fuses

92-93

LA60Q Semiconductor Fuses

94

LA60X Semiconductor Fuses

95

LA70QS Semiconductor Fuses

96-97

LA70QS French Cylindrical Fuses

98

LA100P Semiconductor Fuses

99-100

LA120X Semiconductor Fuses

101

Square Body Semiconductor Fuses

102-106

Fork-Lift and Stud-Mounted Fuses

107

Cable Limiters

108

LGR/LMF In-Line Fuses

109

LHR Holder

109

www.littelfuse.com

Special Purpose Fuses

Semiconductor Fuses
150 – 1300 VAC • Very Fast Acting • 1 – 6000 Amperes

Semiconductor Fuses
Littelfuse Semiconductor fuses are very fast acting fuses designed
specifically for the protection of diodes, thyristors, triacs, and other
solid-state power semiconductor devices. These fuses are used in
power electronic applications including variable speed drives, power
rectifiers, UPS systems, and DC power supplies. They can be used
wherever extremely fast acting, current-limiting fuses are needed to
provide superior protection against the potentially damaging effects of
short-circuit currents.
The extensive line of Littelfuse Semiconductor fuses includes the
traditional round body fuses, enhanced state-of-the-art round body
fuses, and North American style square body fuses. Available ratings
range from 150 to 1300 volts and up to 6000 amps.

Applications
Semiconductor fuses are designed specifically for supplementary
protection of semiconducting devices such as silicon controlled rectifiers
(SCR’s), diodes, thyristors, triacs, transistors, and similar solid-state
devices. These devices are used in power equipment including variable
speed drives, power rectifiers, UPS systems, DC power supplies, and in
a wide range of electronic equipment.
May be used wherever extremely fast acting, current-limiting fuses with
no time-delay are required.

Special Purpose Fuses

Features & Benefits
• Extremely current-limiting
• Low I2t and peak let-through currents
• Low watts loss
• High Interrupting ratings
• UL Recognized
• Wide range of ampere ratings
• Optional mounting types
• DC ratings
• Superior cycling abilities
• Compact sizes
• Optional blown fuse indicators

Ratings
150V:
250V:
300V:
500V:
600V:
700V:
1000V:
1200V:
1300V:

1 – 6000A
1 – 4500A
35 – 4500A
10 – 1200A
1 – 2000A
6 – 2500A
15 – 1000A
1 – 30A
50 – 1800A

Recommended Fuse Blocks:
LSCR and 1LS series: Refer to the Blocks & Holders section of this catalog
for additional information.

84

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

Traditional Semiconductor Fuses
150/250/500/600/700 VAC • Very Fast Acting • 1 – 1200 Amperes

Specifications

Series & Voltage
Ampere
Ratings

L25S

150V AC
250V AC
150V DC (1 – 60A)
250V DC (1 – 200A)
100V DC (70 – 1000A) 200V DC (225 – 800A)

L15S 1
L15S 2
L15S 3
L15S 4
L15S 5
L15S 6
L15S 7
L15S 8
L15S 9
L15S 10
L15S 12
L15S 15
–
L15S 20
L15S 25
L15S 30
L15S 35
L15S 40
L15S 45
L15S 50
L15S 60
L15S 70
L15S 80
L15S 90
L15S 100
–
L15S 125
L15S 150
–
L15S 200
–
L15S 250
–
L15S 300
L15S 350
L15S 400
L15S 450
L15S 500
–
L15S 600
–
L15S 800
–
L15S 1000
–

L25S 1
L25S 2
L25S 3
L25S 4
L25S 5
L25S 6
–
L25S 8
–
L25S 10
L25S 12
L25S 15
–
L25S 20
L25S 25
L25S 30
L25S 35
L25S 40
L25S 45
L25S 50
L25S 60
L25S 70
L25S 80
L25S 90
L25S 100
–
L25S 125
L25S 150
L25S 175
L25S 200
L25S 225
L25S 250
L25S 275
L25S 300
L25S 350
L25S 400
L25S 450
L25S 500
–
L25S 600
L25S 700
L25S 800
–
–
–

L50S

L70S

500V AC
450V DC

L60S

KLC‡

600V AC

600V AC

700V AC
650V DC

–
–
–
–
–
–
–
–
–
L50S 10
L50S 12
L50S 15
–
L50S 20
L50S 25
L50S 30
L50S 35
L50S 40
–
L50S 50
L50S 60
L50S 70
L50S 80
L50S 90
L50S 100
–
L50S 125
L50S 150
L50S 175
L50S 200
L50S 225
L50S 250
L50S 275
L50S 300
L50S 350
L50S 400
L50S 450
L50S 500
L50S 550
L50S 600
L50S 700
L50S 800
LA50P9004
LA50P10004
LA50P12004

L60S 1
L60S 2
L60S 3
L60S 4
L60S 5
L60S 6
–
L60S 8
–
L60S 10
L60S 12
L60S 15
L60S 17 1⁄2
L60S 20
L60S 25
L60S 30
L60S 35
L60S 40
L60S 45
L60S 50
L60S 60
L60S 70
L60S 80
L60S 90
L60S 100
–
L60S 125
L60S 150
L60S 175
L60S 200
L60S 225
L60S 250
–
L60S 300
L60S 350
L60S 400
L60S 450
L60S 500
–
L60S 600
L60S 700
L60S 800
–
–
–

KLC 1
KLC 2
KLC 3
KLC 4
KLC 5
KLC 6
KLC 7
KLC 8
–
KLC 10
KLC 12
KLC 15
KLC 17 1⁄2
KLC 20
KLC 25
KLC 30
KLC 35
KLC 40
KLC 45
KLC 50
KLC 60
KLC 70
KLC 80
KLC 90
KLC 100
KLC 110
KLC 125
KLC 150
KLC 175
KLC 200
KLC 225
KLC 250
–
KLC 300
KLC 350
KLC 400
KLC 450
KLC 500
–
KLC 600
KLC 700
KLC 800
–
–
–

–
–
–
–
–
–
–
–
–
L70S 10
–
L70S 15
–
L70S 20
L70S 25
L70S 30
L70S 35
L70S 40
–
L70S 50
L70S 60
L70S 70
L70S 80
L70S 90
L70S 100
–
L70S 125
L70S 150
L70S 175
L70S 200
L70S 225
L70S 250
–
L70S 300
L70S 350
L70S 400
L70S 450
L70S 500
–
L70S 600
L70S 700
L70S 800
LA70P9004
LA70P10004
LA70P12004

Voltage Ratings:
L15S:

L25S:

L50S:
L60S:
KLC:
L70S:

150 V AC/DC (1 – 60A)
150 VAC (70 – 1000A)
100 VDC (70 – 1000A)
250 V AC/DC (1 – 200A)
250 VAC (225 – 800A)
200 VDC (225 – 800A)
500 VAC/450 VDC
600 VAC
600 VAC
700VAC/650VDC

Interrupting Rating:
AC:
200,000 rms amperes
(L15S series 100,000A)
DC:
20,000 amperes
Ampere Range:
1 – 1200 amperes
See Rating Table for ratings available in each
series.
Approvals:
UL Recognized under the Components
Program and CSA Recognized under the
Component Acceptance Program.
UL File No: E71611
CSA File No: LR29862
L25S series fuses are Littelfuse Certified for
DC ratings shown in Rating Table.

Special Purpose Fuses

1
2
3
4
5
6
7
8
9
10
12
15
17 1⁄ 2
20
25
30
35
40
45
50
60
70
80
90
100
110
125
150
175
200
225
250
275
300
350
400
450
500
550
600
700
800
900
1000
1200

L15S

‡ KLC series fuses are recommended for replacement use only.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

85

Special Purpose Fuses

Traditional Semiconductor Fuses
150/250/500/600/700 VAC • Very Fast Acting • 1 – 1000 Amperes
L15S SERIES, 150 VOLTS AC
(Replaces KLA, KLW, L13S)
Ampere
Rating

Fig.
No.

1 – 30

1

31 – 60

1

61 – 450

3

451 – 1000

3

Dimensions in Inches (mm in parentheses)
A
11⁄ 2
(38.1)
2
(50.8)
1 5 ⁄32
(29.4)
11⁄ 4
(31.8)

B
—
—
1 7⁄ 8
(47.6)
115 ⁄16
(49.2)

C
⁄
(9.5)
5 8
⁄
(15.9)
2 3 ⁄16
(55.6)
2 9 ⁄16
(65.1)

D
⁄
(10.3)
13 16
⁄
(20.6)
2 21 ⁄ 32
(67.5)
3 1⁄ 2
(88.9)

3 8

13 32

E

F

G

H

—

—

—

—

—

—

—

—

1
(25.4)
1 1⁄ 2
(38.1)

43 64

5 16

⁄
(7.9)
13 32
⁄
(10.3)

3 16

⁄
(4.8)
14
⁄
(6.4)

G

H

⁄
(17.1)
1
(25.4)

L25S SERIES, 250 VOLTS AC
(Replaces KLB)
Ampere
Rating

Fig.
No.

Special Purpose Fuses

1 – 30

1

31 – 60

2

61 – 200

3

201 – 700

3

701 – 800

3

Dimensions in Inches (mm in parentheses)
A
2
(50.8)
15 ⁄8
(41.3)
15 ⁄8
(41.3)
119 ⁄32
(40.5)
119 ⁄32
(40.5)

B
—
2 1⁄4
(57.2)
2 5 ⁄ 16
(58.7)
2 9 ⁄32
(57.9)
2 9 ⁄32
(57.9)

C
⁄
(12.7)
2 1⁄2
(63.5)
2 7⁄16
(61.9)
2 29 ⁄ 32
(73.8)
2 29 ⁄ 32
(73.8)

D
⁄
(14.3)
3 3 ⁄16
(81.0)
3 1⁄8
(79.4)
3 27⁄32
(97.6)
3 27⁄32
(97.6)

12

E

9 16

F

—

—

—

—

13 16

23 32

11 32

⁄
(8.7)
5 16
⁄
(7.9)
13 32
⁄
(10.3)
13 32
⁄
(10.3)

18
⁄
(3.2)
3 16
⁄
(4.8)
14
⁄
(6.4)
14
⁄
(6.4)

G

H

—

—

11 32

1 8
⁄
(3.2)
1 8
⁄
(3.2)
3 16
⁄
(4.8)
14
⁄
(6.4)
14
⁄
(6.4)
3 8
⁄
(9.5)

⁄
(20.6)
1 7⁄32
(31.0)
11⁄ 2
(38.1)
2
(50.8)

⁄
(18.3)
1
(25.4)
1
(25.4)
11⁄ 2
(38.1)

L50S SERIES, 500 VOLTS AC / 450 VOLTS DC
(Replaces KLH)
Ampere
Rating

Fig.
No.

10 – 30

1

31 – 60

2

61 – 100

3

101 – 200

3

201 – 400

3

401 – 600

3

601 – 800

3

A
2
(50.8)
15 ⁄8
(41.3)
2 1 ⁄8
(54.0)
2 1 ⁄8
(54.0)
2 3 ⁄ 32
(53.2)
2 7⁄ 32
(56.4)
2 7⁄ 32
(56.4)

B
—
2 1⁄4
(57.2)
2 11 ⁄16
(68.3)
2 13 ⁄16
(71.4)
2 25 ⁄ 32
(70.6)
2 29 ⁄ 32
(73.8)
4 9 ⁄ 32
(108.7)

Dimensions in Inches (mm in parentheses)
C
D
E
F
12
9 16
⁄
⁄
—
—
(12.7)
(14.3)
13 16
23 32
2 1⁄ 2
3 3 ⁄16
⁄
⁄
(63.5)
(81.0)
(20.6)
(18.3)
3 4
3
3 5 ⁄8
1
⁄
(76.2)
(92.1)
(25.4)
(19.1)
2 15 ⁄16
3 5 ⁄8
1 7⁄ 32
1
(74.6)
(92.1)
(31.0)
(25.4)
3 13 ⁄ 32
4 11 ⁄ 32
11⁄2
1
(86.5)
(110.3)
(38.1)
(25.4)
17 32
15 32
3 ⁄
4 ⁄
2
11⁄2
(89.7)
(113.5)
(50.8)
(38.1)
4 5 ⁄8
6 15 ⁄ 32
2 1⁄ 2
2
(117.5)
(164.3)
(63.5)
(50.8)

D

Contact Littelfuse for characteristic curves.

A

Fig. 1

86

F
G

C

www.littelfuse.com

⁄
(8.7)
11 32
⁄
(8.7)
5 16
⁄
(7.9)
13 32
⁄
(10.3)
13 32
⁄
(10.3)
17 32
⁄
(13.5)

A
B
C
D

H
E

Fig, 2

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

Traditional Semiconductor Fuses
150/250/500/600/700 VAC • Very Fast Acting • 1 – 1000 Amperes
L60S SERIES, 600 VOLTS AC
Ampere
Rating

Fig.
No.

1 – 30

1

31 – 60

2

61 – 100

2

101 – 200

2

201 – 400

2

401 – 600

2

601 – 800

2

A
5
(127.0)
2 25 ⁄ 32
(70.6)
2 29 ⁄ 32
(73.8)
2 29 ⁄ 32
(73.8)
2 29 ⁄ 32
(73.8)
2 7⁄ 8
(73.0)
3 1 ⁄ 32
(77.0)

B
—
3 7⁄ 16
(87.3)
3 17⁄32
(89.7)
3 9 ⁄16
(90.5)
3 31 ⁄ 32
(100.8)
3 31 ⁄ 32
(100.8)
5 5 ⁄ 32
(133.4)

Dimensions in Inches (mm in parentheses)
C
D
E
F
5 8
13 16
⁄
⁄
—
—
(15.9)
(20.6)
13 16
23 32
3 11 ⁄16
4 3 ⁄8
⁄
⁄
(93.7)
(111.1)
(20.6)
(18.3)
23 32
3 25 ⁄32
4 15 ⁄32
11 ⁄ 16
⁄
(96.0)
(113.5)
(27.0)
(18.3)
3 3 ⁄4
413 ⁄ 32
1 5 ⁄ 16
1
(95.3)
(111.9)
(33.3)
(25.4)
4 5 ⁄ 32
5 1⁄ 8
137⁄64
1
(105.6)
(130.2)
(40.1)
(25.4)
4 9 ⁄64
5 1⁄ 8
2 1 ⁄16
11⁄ 2
(105.2)
(130.2)
(52.8)
(38.1)
5 11 ⁄32
7 1⁄ 4
2 1⁄2
2
(135.7)
(184.2)
(63.5)
(50.8)

G

H

—

—

11 32

18
⁄
(3.2)
18
⁄
(3.2)
3 16
⁄
(4.8)
14
⁄
(6.4)
14
⁄
(6.4)
3 8
⁄
(9.5

⁄
(8.7)
11 32
⁄
(8.7)
5 16
⁄
(7.9)
13 32
⁄
(10.3)
13 32
⁄
(10.3)
17 32
⁄
(13.5)

L70S SERIES, 700 VOLTS AC / 650 VOLTS DC
Ampere
Rating

Fig.
No.

10 – 30

1
3

61 – 100

3

101 – 200

3

201 – 400

3

401 – 600

3

601 – 800

F

4

B
—
3 7⁄16
(87.3)
3 9 ⁄16
(90.5)
3 17⁄ 32
(89.7)
3 17⁄ 32
(89.7)
4 29 ⁄ 32
(124.6)
5 5 ⁄16
(134.9)

Dimensions in Inches (mm in parentheses)
C
D
E
F
G
12
9 16
⁄
⁄
—
—
—
(12.7)
(14.3)
43 64
11 32
3 25 ⁄ 32
4 3 ⁄8
1
⁄
⁄
(96.0)
(111.1)
(25.4)
(17.1)
(8.7)
29 32
5 16
3 11 ⁄16
4 3 ⁄8
1 7⁄ 32
⁄
⁄
(93.7)
(111.1)
(31.0)
(22.9)
(7.9)
13 32
4 5 ⁄ 32
5 3 ⁄ 32
1 1⁄ 2
1
⁄
(105.6) (129.4)
(38.1)
(25.4)
(10.3)
13 32
4 5 ⁄ 32
5 3 ⁄ 32
2
1 1⁄ 2
⁄
(105.6) (129.4)
(50.8)
(38.1)
(10.3)
17 32
5 1⁄ 4
7 3 ⁄ 32
2 1⁄ 2
2
⁄
(133.4) (180.2)
(63.5)
(50.8)
(13.5)
5 8
6 13 ⁄16
2 7⁄ 8
2
⁄
—
(173.0)
(73.0)
(50.8)
(15.9)

H

J

—

—

18

⁄
(3.2)
3 16
⁄
(4.8)
14
⁄
(6.4)
14
⁄
(6.4)
3 8
⁄
(9.5)
3 8
⁄
(9.5)

—
Special Purpose Fuses

31 – 60

A
2
(50.8)
2 7⁄ 8
(73.0)
2 7⁄ 8
(73.0)
2 27⁄ 32
(72.2)
2 27⁄ 32
(72.2)
2 27⁄ 32
(72.2)
3 5 ⁄16
(84.1)

—
—
—
—
5 16

⁄
(7.9)

KLC SERIES, 600 VOLTS AC
G

H

A
B
C
D

E

Fig. 3

F
G

A
B
C

Ampere
Rating

Fig.
No.

1 – 30

2

31 – 60

2

61 – 100

3

101 – 200

3

201 – 400

3

401 – 800

3

J
H
E

Fig. 4

A
1 7⁄ 8
(47.6)
2 3 ⁄4
(69.9)
2 7⁄ 8
(73.0)
2 27⁄ 32
(72.2)
2 27⁄ 32
(72.2)
2 27⁄ 32
(72.2)

B
2 1⁄ 2
(63.5)
3 3 ⁄8
(85.7)
3 21 ⁄ 32
(92.9)
3 17⁄ 32
(89.7)
4 21 ⁄ 32
(118.3)
4 21 ⁄ 32
(118.3)

Dimensions in Inches (mm in parentheses)
C
D
E
F
9 16
13 32
2 7⁄ 8
⁄
⁄
—
(73.0)
(14.3)
(10.3)
13 16
23 32
3 5 ⁄8
4 5 ⁄16
⁄
⁄
(92.1)
(109.5)
(20.6)
(18.3)
3 4
4 1 ⁄16
5
1
⁄
(103.2)
(127.0)
(25.4)
(19.1)
4 3 ⁄8
5 3 ⁄ 32
11⁄ 2
1
(111.1)
(129.4)
(38.1)
(25.4)
4 27⁄ 32
6 1⁄ 4
2
1 5 ⁄8
(123.0)
(158.8)
(50.8)
(41.3)
5 11 ⁄ 32
6 1⁄4
2 1⁄ 2
2
(135.7)
(158.8)
(63.5)
(50.8)

G
⁄
(6.4)
11 32
⁄
(8.7)
13 32
⁄
(10.3)
13 32
⁄
(10.3)
9 16
⁄
(14.3)
9 16
⁄
(14.3)
14

H
⁄
(1.2)
1 8
⁄
(3.2)
1 8
⁄
(3.2)
14
⁄
(6.4)
14
⁄
(6.4)
3 8
⁄
(9.5)
3 64

Contact Littelfuse for characteristic curves.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

87

Special Purpose Fuses

LA15QS Semiconductor Fuses
150 VAC • Very Fast Acting • 1 – 6000 Amperes
Littelfuse LA15QS series Semiconductor fuses were designed for the
specific protection of diodes and other semiconductor devices rated
150VAC/DC. The LA15QS product line compact design is perfect for
those applications that have limitations on available space.

Features
• Low I2t minimizes damage to protected components on short-circuit.
• Controlled arc voltage reduces stress to circuit components during
fuse clearing.
• Choice of mounting types provides options for unique termination
requirements.
• Indicator options allow identification of blown fuses.

Applications
Protection of heavy duty devices such as electromechanical rectifiers.

Ordering Information
LA 15 QS 400 -4 TI
Littelfuse

Special Purpose Fuses

Voltage
(150)

Style
Ampere Rating
Mounting Type
Ferrule
Ferrule, midget dim.
Blades/Bolt-in
Hockey Puck, bolt-in

1
2
4
128

Integral BlownFuse Indicator
Trigger Indicator
Trigger Actuator

TI
IL

Note: Mounting types and integral blown fuse indicators are optional for
specified ratings.

Specifications
Voltage Rating:

Contact Littelfuse for characteristic curves.

88

Interrupting Rating:
Ampere Range:
Approvals:

www.littelfuse.com

AC: 150 volts
DC: 150 volts
100,000 Amperes
1 – 6000 Amperes
UL Recognized under the components program.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA15QS Semiconductor Fuses
150 VAC • Very Fast Acting • 1 – 6000 Amperes

Catalog Numbers & Technical Data
Maximum
Watts Loss @
Ampere
Littelfuse
Mounting
Clearing I2 t @150 Rated Current
Rating Catalog Number
Type
VAC (A 2S x 10 3 )
(W)
LA15QS1-2
LA15QS2-2
LA15QS3-2
LA15QS4-2
LA15QS5-2
LA15QS6-2
LA15QS7-2
LA15QS8-2
LA15QS10-2
LA15QS12-2
LA15QS15-2
LA15QS20-2
LA15QS25-2
LA15QS30-2
LA15QS35-1
LA15QS40-1
LA15QS40-4TI
LA15QS45-1
LA15QS50-1
LA15QS50-4
LA15QS55-1
LA15QS60-1
LA15QS70-4
LA15QS70-4TI
LA15QS80-4
LA15QS80-4TI
LA15QS90-4
LA15QS100-4
LA15QS100-4TI
LA15QS130-4
LA15QS130-4TI
LA15QS150-4
LA15QS150-4IL
LA15QS150-4TI
LA15QS200-4
LA15QS200-4IL
LA15QS250-4

2
2
2
2
2
2
2
2
2
2
2
2
2
2
1
1
4TI
1
1
4
1
1
4
4TI
4
4TI
4
4
4TI
4
4TI
4
4IL
4TI
4
4IL
4

0.0002
0.001
0.003
0.007
0.012
0.022
0.011
0.015
0.019
0.030
0.042
0.072
0.14
0.25
0.21
0.28
0.39
0.34
0.47
0.64
Contact Factory
0.94
2
2
2.5
2.5
3.1
3.6
3.6
5.3
5.3
6.8
6.8
6.8
9
9
15

Figure 1

0.68
1.3
1.7
2.1
2.8
3.1
2.2
2.5
2.6
3
3
4
5.2
5.6
9
10
3.1
12
13
4
Contact Factory
14
5.6
5.6
8
8
9
10
10
14
14
16
16
16
22
22
22

250
300
300
300
350
350
400
400
400
450
450
500
500
600
600
800
1000
1000
1000
1000
1000
1200
1200
1500
1500
2000
2000
2500
2500
3000
3000
3500
4000
4000
5000
6000

LA15QS250-4TI
LA15QS300-4
LA15QS300-4IL
LA15QS300-4TL
LA15QS350-4
LA15QS350-4TI
LA15QS400-4
LA15QS400-4IL
LA15QS400-4TI
LA15QS450-4
LA15QS450-4IL
LA15QS500-4
LA15QS500-4IL
LA15QS600-4
LA15QS600-4IL
LA15QS800-4
LA15QS1000-4
LA15QS1000-4IL
LA15QS1000-4TI
LA15QS1000-128
LA15QS1000-128IL
LA15QS1200-128
LA15QS1200-128IL
LA15QS1500-128
LA15QS1500-128IL
LA15QS2000-128
LA15QS2000-128IL
LA15QS2500-128
LA15QS2500-128IL
LA15QS3000-128
LA15QS3000-128IL
LA15QS3500-128
LA15QS4000-128
LA15QS4000-128IL
LA15QS5000-128
LA15QS6000-128

Figure 2

Figure 4

4TI
4
4IL
4TI
4
4TI
4
4IL
4TI
4
4IL
4
4IL
4
4IL
4
4
4IL
4TI
128
128IL
128
128IL
128
128IL
128
128IL
128
128IL
128
128IL
128
128
128IL
128
128

15
22
22
22
32
32
40
40
40
50
50
90
90
130
130
290
520
520
520
540
540
680
680
1200
1200
1900
1900
3200
3200
4800
4800
6500
8500
8500
Contact Factory
Contact Factory

27
33
33
33
40
40
45
45
45
50
50
30
30
35
35
57
75
75
75
88
88
100
100
130
130
165
165
195
195
240
240
260
270
270
Contact Factory
Contact Factory

Special Purpose Fuses

1
2
3
4
5
6
7
8
10
12
15
20
25
30
35
40
40
45
50
50
55
60
70
70
80
80
90
100
100
130
130
150
150
150
200
200
250

Maximum
Watts Loss @
Ampere
Littelfuse
Mounting
Clearing I2 t @150 Rated Current
Rating Catalog Number
Type
VAC (A 2S x 10 3 )
(W)

Figure 3

Figure 5

Figure 6

Figure 7

Figure 8

Dimensions

Dimensions for reference only.

Amperes

Mount.
Type

Fig.
No.

1 – 30
35 – 60
70 – 450
500 – 1000
750 – 2000
2500 – 3000
3500 – 4000
5000 – 6000

2
1
4, 4TI*, 4IL*
4, 4TI*, 4IL*
128, 128IL*
128, 128IL*
128, 128IL*
128

1
1
2, 3*
2, 3*
4, 5*
4, 5*
6, 7*
8

A
1.50
2.00
2.66
3.50
1.88
1.88
1.88
2.38

(38.1)
(50.8)
(67.6)
(88.9)
(47.9)
(47.9)
(47.9)
(60.5)

Dimensions in Inches (mm in parentheses)
C
D
E
F

B
0.41 (10.4)
0.81 (20.6)
1.13 (28.7)
1.50 (38.1)
2.00 (50.8)
3.00 (76.2)
3.50 (88.9)
5.75 (146)

–
–
1.16 (29.5)
1.25 (31.8)
1.63 (41.4)
1.63 (41.4)
1.63 (41.4)
1.88 (47.7)

–
–
2.19 (55.6)
2.56 (65.0)
1.75 (44.5)
2.50 (63.5)
3.00 (76.2)
5.00 (127)

–
–
1.91 (48.5)
1.94 (49.3)
1.00 (25.4)
1.50 (38.1)
1.06 (27.0)
1.50 (38.1)

–
–
0.31 (7.9)
0.41 (10.4)
–
–
1.06 (27.0)
1.50 (38.1)

G

H

–
–
0.88 (22.4)
1.00 (25.4)
–
–
–
–

–
–
0.19 (4.8)
0.25 (6.4)
–
–
–
–

Tap
–
–
–
–
3
⁄ 8 -24-1⁄2 deep
1
⁄2 -20-1⁄ 2 deep
1
⁄2 -20-1⁄ 2 deep
1
⁄2 -20-1⁄ 2 deep

* Optional Trigger Actuator (IL)
© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

89

Special Purpose Fuses

LA30QS Semiconductor Fuses
300 VAC • Very Fast Acting • 35 – 4500 Amperes
Littelfuse LA30QS series Semiconductor protection fuses are intended
for the protection of Power Semiconductors such as diodes, phase
control SCR’s and other power semiconductor devices. The LA30QS is
recommended for new applications providing solutions for your critical
protection needs for 300V and less semiconductors.

Features
• Low I2t minimizes damage to protected components on short-circuit.
• Controlled arc voltage reduces stress to circuit components during
fuse clearing.
• Choice of mounting types provides options for unique termination
requirements.
• Indicator options allow identification of blown fuses.
• Superior DC capabilities.

Applications
Protection of 300 volt heavy duty rectifiers and similar heavy duty
power supplies.

Ordering Information

Special Purpose Fuses

LA 30 QS 600 -4 TI
Littelfuse
Voltage
(300)

Style
Ampere Rating
Mounting Type
Ferrule
Blades/Bolt-in
Hockey Puck, bolt-in

1
4
128

Integral BlownFuse Indicator
Trigger Indicator
Trigger Actuator

TI
IL

Note: Mounting types and integral blown fuse indicators are optional for
specified ratings.

Specifications
Voltage Rating:

Contact Littelfuse for characteristic curves.

90

Interrupting Rating:
Ampere Range:
Approvals:

www.littelfuse.com

AC: 300 volts
DC: 300 volts
200,000 Amperes
35 – 4500 Amperes
UL Recognized under the components program.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA30QS Semiconductor Fuses
300 VAC • Very Fast Acting • 35 – 4500 Amperes

Catalog Numbers & Technical Data
Littelfuse
Catalog
Number

Mounting
Type

35
40
50
60
70
80
90
100
100
125
130
150
150
175
200
200
225
250
250
300
300
350
400
400
400
450

LA30QS35-4
LA30QS40-4
LA30QS50-4
LA30QS60-4
LA30QS70-4
LA30QS80-4
LA30QS90-4
LA30QS100-4
LA30QS100-4TI
LA30QS125-4
LA30QS130-4
LA30QS150-4
LA30QS150-4TI
LA30QS175-4
LA30QS200-4
LA30QS200-4TI
LA30QS225-4
LA30QS250-4
LA30QS250-4TI
LA30QS300-4
LA30QS300-4TI
LA30QS350-4
LA30QS400-4
LA30QS400-4IL
LA30QS400-4TI
LA30QS450-4

4
4
4
4
4
4
4
4
4TI
4
4
4
4TI
4
4
4TI
4
4
4TI
4
4TI
4
4
4IL
4TI
4

Maximum
Clearing I2 t
@300 VAC
(A 2S x 10 3 )
0.9
1.2
2
2.7
1.6
2.6
3.2
4.1
4.1
6.3
6.3
9.3
9.3
10
15
15
22
25
25
37
37
62
83
83
83
130

Figure 1

Watts Loss
@ Rated
Current (W)
6.4
7
9.9
11.6
11
11
13
13
13
16
16
19
19
27
30
30
33
41
41
47
47
49
56
56
56
53

Ampere
Rating

Littelfuse
Catalog
Number

Mounting
Type

500
550
600
600
600
700
700
800
800
800
1000
1000
1200
1500
1500
1600
2000
2000
2500
2500
3000
3500
3500
4000
4500

LA30QS500-4
LA30QS550-4
LA30QS600-4
LA30QS600-4TI
LA30QS600-4IL
LA30QS700-4
LA30QS700-128
LA30QS800-4
LA30QS800-4IL
LA30QS800-128
LA30QS1000-128
LA30QS1000-128IL
LA30QS1200-128
LA30QS1500-128
LA30QS1500-128IL
LA30QS1600-128
LA30QS2000-128
LA30QS2000-128IL
LA30QS2500-128
LA30QS2500-128IL
LA30QS3000-128
LA30QS3500-128
LA30QS3500-128IL
LA30QS4000-128
LA30QS4500-128

4
4
4
4TI
4IL
4
128
4
4IL
128
128
128IL
128
128
128IL
128
128
128IL
128
128IL
128
128
128IL
128
128

Figure 2

Figure 4

Maximum
Clearing I2 t
@300 VAC
(A 2S x 10 3 )
160
190
230
230
230
260
260
330
330
330
460
460
880
1400
1400
1690
2600
2600
4000
4000
4700
6500
6500
8600
11000

Watts Loss
@ Rated
Current (W)
59
65
69
69
69
90
73
108
108
84
105
105
110
140
140
150
190
190
230
230
340
380
380
450
500

Special Purpose Fuses

Ampere
Rating

Figure 3

Figure 5

Figure 6
TAP

F

1.17

E

[ 29.8 mm ]

D

C
A

0.50
[ 12.8 mm ]

Dimensions

B

Dimensions for reference only.

Amperes

Mount. Type

Fig. No.

35 – 60
70 – 200
225 – 700
700 – 1200
1500 – 2500
3000 – 4500

4
4
4, 4IL*
128
128, 128IL*
128, 128IL*

1
2
2, 3*
4
5, 6*
5, 6*

A
3.19 (81.0)
3.13 (79.5)
3.84 (97.5)
2.59 (65.8)
2.59 (65.8)
2.59 (65.8)

B
0.81 (20.6)
1.22 (31.0)
1.50 (38.1)
3.00 (76.2)
3.50 (88.9)
4.50 (114)

Dimensions in Inches (mm in parentheses)
C
D
E
F
1.63 (41.4) 2.50 (63.5) 2.25 (57.5) 0.34 (8.6)
1.63 (41.4) 2.44 (62.0) 2.31 (58.7) 0.31 (7.9)
1.59 (40.1) 2.91 (73.9) 2.28 (57.9) 0.41 (10.4)
2.34 (59.4) 2.50 (63.5) 1.50 (38.1)
–
2.34 (59.4) 3.00 (76.2) 1.50 (38.1) 1.50 (38.1)
2.34 (59.4) 3.75 (95.3) 1.50 (38.1) 1.50 (38.1)

G
0.72 (18.3)
1.00 (25.4)
1.00 (25.4)
–
–
–

H
0.13 (3.3)
0.19 (4.8)
0.25 (6.4)
–
–
–

Tap
–
–
–
3 8
⁄ -24-1⁄ 2 deep
3 8
⁄ -24-1⁄ 2 deep
12
⁄ -20-1⁄ 2 deep

* Optional Actuator (IL)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

91

Special Purpose Fuses

LA50QS Semiconductor Fuses
500 VAC • Very Fast Acting • 35 – 1200 Amperes
In response to new equipment requirements, Littelfuse LA50QS
series fuses were developed to improve the overall performance
of semiconductor fuses. The LA50QS provides the best protection
features including lower I2t, longer life when subjected to cyclic loading
and lower watts loss. LA50QS is today’s choice for the protection of
dynamic solid state equipment.

Features
•
•
•
•
•

Lowest I2t for greatest protection of semiconductor circuits.
Low watts loss for cooler operation.
Superior cycling ability gives an equipment design advantage.
State-of-the-art protection for 500 volt equipment.
Ultra compact sizes allow down-sizing of existing equipment.

Applications
Protection of 500 volts or less solid state equipment such as motor
drives, UPS, inverters, etc.

Ordering Information
LA 50 QS 250 -4

Special Purpose Fuses

Littelfuse
Voltage
(500)

Style
Ampere Rating

Mounting Type
(Blades/Bolt-in)

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

92

www.littelfuse.com

AC: 500 volts
DC: 500 volts
AC:
200,000 Amperes
DC: 100,000 Amperes
35 – 1200 Amperes
UL Recognized under the components program
CSA Certified.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA50QS Semiconductor Fuses
500 VAC • Very Fast Acting • 35 – 1200 Amperes

Catalog Numbers & Technical Data
Ampere
Rating

Littelfuse
Catalog
Number

35
40
50
60
70
80
90
100
125
150
175
200
225

LA50QS35-4
LA50QS40-4
LA50QS50-4
LA50QS60-4
LA50QS70-4
LA50QS80-4
LA50QS90-4
LA50QS100-4
LA50QS125-4
LA50QS150-4
LA50QS175-4
LA50QS200-4
LA50QS225-4

Maximum
Mounting
Clearing I2 t @500
Type
VAC (A 2S x 10 3 )
4
4
4
4
4
4
4
4
4
4
4
4
4

0.56
0.69
1.1
1.8
1.9
2.6
3.6
4.4
5.6
9
15
20
25

Watts Loss
@ Rated
Current (W)
6
7
8
10
12
14
15
17
21
25
29
33
37

Ampere
Rating

Littelfuse
Catalog
Number

250
300
350
400
450
500
600
700
800
900
1000
1200

LA50QS250-4
LA50QS300-4
LA50QS350-4
LA50QS400-4
LA50QS450-4
LA50QS500-4
LA50QS600-4
LA50QS700-4
LA50QS800-4
LA50QS900-4
LA50QS1000-4
LA50QS1200-4

Maximum
Mounting
Clearing I2 t @500
Type
VAC (A 2S x 10 3 )
4
4
4
4
4
4
4
4
4
4
4
4

29
55
88
98
130
160
220
270
360
500
560
930

Watts Loss
@ Rated
Current (W)
41
49
57
65
69
77
92
110
130
140
160
175

Special Purpose Fuses

Dimensions
Dimensions for reference only.
Amperes

Mount.
Type

35 – 100

4

125 – 200

4

225 – 400

4

450 – 600

4

700 – 800

4

900 – 1200

4

Dimensions in Inches (mm in parentheses)
A
3.63
(92.2)
3.63
(92.2)
4.34
(110)
4.47
(114)
6.47
(164.3)
6.97
(177.0)

B
1.00
(25.4)
1.22
(31.0)
1.50
(38.1)
2.00
(50.8)
2.50
(63.5)
3.00
(76.2)

C
2.13
(54.1)
2.13
(54.1)
2.09
(53.1)
2.22
(56.4)
2.22
(56.4)
3.22
(81.8)

D
2.94
(74.7)
2.94
(74.7)
3.41
(86.6)
3.53
(89.7)
5.00
(127.0)
5.47
(138.9)

E
2.75
(69.9)
2.81
(71.4)
2.78
(70.6)
2.91
(73.9)
3.44
(87.3)
4.47
(113.5)

F
0.31
(7.9)
0.31
(7.9)
0.41
(10.4)
0.41
(10.4)
0.53
(13.5)
0.63
(15.9)

G
0.75
(19.1)
1.00
(25.4)
1.00
(25.4)
1.50
(38.1)
1.50
(38.1)
2.38
(60.3)

H
0.13
(3.3)
0.19
(4.8)
0.25
(6.4)
0.25
(6.4)
0.25
(6.4)
0.44
(11.1)

Contact Littelfuse for characteristic curves.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

93

Special Purpose Fuses

LA60Q Semiconductor Fuses
600 VAC • Very Fast Acting • 5 – 40 Amperes
Littelfuse LA60Q semiconductor protection fuses feature a 600 volt
AC/DC rating in a compact size (11⁄ 2” x 13 ⁄ 32”). LA60Q also has the lowest
I2t of all similar fuses and excellent cycling ability. Applications include
inverters and small equipment requiring extremely fast response to
faults, without the need to carry sustained heavy overloads.

Features
• Lowest I2t of any fuse this size for greater protection.
• Excellent cycling ability gives advantage in equipment design.

Dimensions (in inches)

Ordering Information
Special Purpose Fuses

LA 60 Q 30 -2
Littelfuse
Voltage
(300)

Style

Catalog Numbers & Technical Data
Ampere
Rating

Littelfuse
Catalog
Number

5
8
10
12
15
20
25
30
35
40

LA60Q5-2
LA60Q8-2
LA60Q10-2
LA60Q12-2
LA60Q15-2
LA60Q20-2
LA60Q25-2
LA60Q30-2
LA60Q35-2
LA60Q40-2

Ampere Rating

Maximum
Mounting
Watts Loss @
Clearing I2 t @600
Type
Rated Current (W)
2
VAC (A S)
2
2
2
2
2
2
2
2
2
2

60
70
110
150
180
330
440
860
1300
1800

0.7
1.1
1.6
2
3
4.4
5.5
5.6
6.4
7

Mounting Type
Ferrule, midget dim. 1-½” x 13/ 32”

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

AC: 600 volts
DC: 600 volts
AC: 200,000 Amperes
DC: 100,000 Amperes
5 – 40 Amperes
UL Recognized under the components program.

Recommended Fuse Blocks
LPSM or L60030M
Contact Littelfuse for characteristic curves.

94

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA60X Semiconductor Fuses
600 VAC • Very Fast Acting • 700 – 2000 Amperes
Littelfuse LA60X semiconductor protection fuses are popular for the
protection of higher voltage heavy rectifiers such as traction rectifiers.
They can carry long sustained overloads common with heavy-duty
apparatus. The compact “hockey puck” design provides high power
protection in a small space.

Features
• Lowest I2t minimizes damage to protected components on
short- circuit.
• Controlled arc voltage reduces stress to circuit components during
fuse clearing.

Applications
Protection of heavy traction and electrochemical as well as rectifiers and
other heavy-duty equipment.

Ordering Information
LA 60 X 700 -128
Littelfuse
Voltage
Figure 1

Figure 2

(300)
Special Purpose Fuses

Style
Ampere Rating
Mounting Type
Hockey Puck, bolt-in

Dimensions

Dimensions for reference only.

Amperes

Mount.
Type

Fig.
No.

700 – 800

128

1

1000 – 1200

128

2

1500 – 2000

128

2

Dimensions in Inches (mm in parentheses)
A
4.00
(102)
4.00
(102)
4.00
(102)

B
3.00
(76.2)
3.50
(88.9)
4.50
(114)

C
3.75
(95.3)
3.75
(95.3)
3.75
(95.3)

D
2.50
(63.5)
3.00
(76.2)
3.75
(95.3)

E
1.50
(38.1)
1.50
(38.1)
1.50
(38.1)

Tap

F
1.50
(38.1)
1.50
(38.1)

3 8

⁄ -24-1⁄ 2 deep

3 8

⁄ -24-1⁄ 2 deep

12

⁄ -20-1⁄ 2 deep

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

AC: 600 volts
AC: 100,000 Amperes
700 – 2000 Amperes
UL Recognized under the components program.

Ampere Ratings

Contact Littelfuse for technical information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

700
800
1000

www.littelfuse.com

1200
1500
1600

1800
2000

95

Special Purpose Fuses

LA70QS Semiconductor Fuses
700 VAC • Very Fast Acting • 35 – 800 Amperes
Littelfuse LA70QS semiconductor fuses were developed to provide
improved performance required by today’s new equipment. The
LA70QS features lower I2t, improved cycling, and lower watts loss. It is
the best choice for the protection of dynamic solid-state equipment.

Features
•
•
•
•
•

Very low I2t improved protection of equipment.
Superior cycling ability for long, reliable life on high cycling loading.
Lower watts loss for cooler operation.
700 Volt AC/DC rating provides greater design versatility.
Compact sizes allow downsizing of equipment.

Applications
Protection of 700 volt or less solid state equipment such as motor
drives, UPS, inverters, etc.

Ordering Information
LA 70 QS 150 -4
Littelfuse
Voltage
Special Purpose Fuses

(300)

Style
Ampere Rating
Mounting Type
Blades/Bolt-in

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

96

www.littelfuse.com

AC: 700 Volts
DC: 700 Volts
AC: 200,000 Amperes
DC: 100,000 Amperes
35 – 800 Amperes
UL Recognized under the components program.
CSA Certified.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA70QS Semiconductor Fuses
700 VAC • Very Fast Acting • 35 – 800 Amperes

Catalog Numbers & Technical Data
Ampere
Rating

Littelfuse
Catalog
Number

35
40
50
60
70
80
90
100
125
125
150
150
175
175

LA70QS35-4
LA70QS40-4
LA70QS50-4
LA70QS60-4
LA70QS70-4
LA70QS80-4
LA70QS90-4
LA70QS100-4
LA70QS125-4
LA70QS125-4K
LA70QS150-4
LA70QS150-4K
LA70QS175-4
LA70QS175-4K

Maximum
Mounting
Watts Loss @
Clearing I2 t @700
Type
Rated Current (W)
VAC (A 2S x 10 3 )
4
4
4
4
4
4
4
4
4
4K
4
4K
4
4K

0.47
0.58
0.88
1.2
1.8
2.3
3
3.6
6.9
6.9
11
11
14
14

6.2
7.5
9.8
12
15
16
20
24
22
22
28
29
35
35

Maximum
Watts Loss @
Ampere
Littelfuse
Mounting
Clearing I2 t @700
Rated Current (W)
Rating Catalog Number Type
VAC (A 2S x 10 3 )
200
200
250
300
350
400
450
450
500
500
600
600
700
800

LA70QS200-4
LA70QS200-4K
LA70QS250-4
LA70QS300-4
LA70QS350-4
LA70QS400-4
LA70QS450-4
LA70QS450-4K
LA70QS500-4
LA70QS500-4K
LA70QS600-4
LA70QS600-4K
LA70QS700-4
LA70QS800-4

4
4
4
4
4
4
4
4K
4
4K
4
4K
4
4

19
19
42
55
72
99
125
125
150
160
222
222
332
433

41
41
42
53
64
75
75
75
92
92
116
116
125
143

Special Purpose Fuses

Dimensions

Dimensions for reference only.

Amperes

Mount. Type

35 – 100

4

125 – 200

4

125 – 200

4K

225 – 400

4

450 – 600

4

450 – 600

4K

700 – 800

4

Dimensions in Inches (mm in parentheses)
A
4.38
(111)
4.38
(111)
5.09
(129)
5.09
(129)
5.09
(129)
7.09
(180)
7.09
(180)

B
1.00
(25.4)
1.22
(31.0)
1.22
(31.0)
1.50
(38.1)
2.00
(50.8)
2.00
(50.8)
2.50
(63.5)

C
2.88
(73)
2.88
(73)
2.88
(73)
2.84
(72.2)
2.84
(72.2)
2.84
(72.2)
2.84
(72.2)

D
3.69
(93.6)
3.69
(93.6)
4.19
(106)
4.16
(106)
4.16
(106)
6.16
(156)
5.28
(134)

E
3.50
(88.9)
3.56
(90.5)
3.50
(88)
3.53
(89.7)
3.53
(89.7)
3.53
(89.7)
4.91
(125)

F
0.31
(7.9)
0.31
(7.9)
0.41
(10.3)
0.40
(10.3)
0.41
(10.3)
0.53
(13.5)
0.53
(13.5)

G
0.75
(19.0)
1.00
(25.4)
1.00
(25.4)
1.50
(38.1)
1.50
(38.1)
1.50
(38.1)
2.00
(50.8)

H
0.13
(3.2)
0.19
(4.8)
0.19
(4.8)
0.25
(6.4)
0.25
(6.4)
0.25
(6.4)
0.38
(9.5)

Contact Littelfuse for characteristic curves.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

97

Special Purpose Fuses

LA70QS French Cylindrical Fuses
690 Volts • Very Fast Acting • 10 – 100 Amperes

Ordering Information
LA 70 QS 20 -14F I
Littelfuse
Voltage
(700)

Style
Ampere Rating
Size
14 x 51mm
22 x 58mm

14F
22F

Optional Striker
(I)
B
C

A

Special Purpose Fuses

Littelfuse French Cylindrical style semiconductor fuses are an extension
to the LA70QS series. They offer a solid-fill design with high interrupting
ratings and an optional striker for visual or remote blown fuse indication.
The international 14x51mm and 22x58mm sizes are accepted
worldwide.

B
C
D

E

A

Catalog Numbers & Technical Data

98

Ampere
Rating

Littelfuse
Catalog
Number
(No Striker)

10
12
16
20
25
32
40
50
20
25
32
40
50
63
80
100

LA70QS10-14F
LA70QS12-14F
LA70QS16-14F
LA70QS20-14F
LA70QS25-14F
LA70QS32-14F
LA70QS40-14F
LA70QS50-14F
LA70QS20-22F
LA70QS25-22F
LA70QS32-22F
LA70QS40-22F
LA70QS50-22F
LA70QS63-22F
LA70QS80-22F
LA70QS100-22F

Littelfuse
Catalog
Body
Number
Size
(With Striker)
LA70QS10-14FI
LA70QS12-14FI
LA70QS16-14FI
LA70QS20-14FI
LA70QS25-14FI
LA70QS32-14FI
LA70QS40-14FI
LA70QS50-14FI
LA70QS20-22FI
LA70QS25-22FI
LA70QS32-22FI
LA70QS40-22FI
LA70QS50-22FI
LA70QS63-22FI
LA70QS80-22FI
LA70QS100-22FI

14x51
14x51
14x51
14x51
14x51
14x51
14x51
14x51
22x58
22x58
22x58
22x58
22x58
22x58
22x58
22x58

Maximum
Watts Loss
Clearing I2 t
@ Rated
@700 VAC
Current (W)
2
3
(A S x 10 )
0.04
0.06
0.10
0.16
0.27
1.50
0.70
1.50
0.076
0.125
0.27
0.48
0.80
1.85
3.80
8.00

3.5
4.4
4.8
5.2
5.8
7.0
10.7
11.6
8.0
10.0
11.0
13.0
14.9
16.0
17.8
19.0

Fuse Size
14x51 (no striker)
22x58 (no striker)
14x51 (with striker)
22x58 (with striker)

Dimensions in mm
A
14
22
14
22

B
51
58
51
58

C
14
16
14
16

D
–
–
7.5
7.5

E
–
–
3.8
3.8

Dimensions for reference only.

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

AC: 690 Volts
DC: 700 Volts
AC: 200,000 Amperes
DC: 100,000 Amperes
10 – 100 Amperes
UL Recognized under the components program.
CSA Certified.

Recommended Fuse Blocks
CYH series for non-striker fuses LA70QS(amp)22F
LPSG series for the striker style LA70QS(amp)22FI

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA100P Semiconductor Fuses
1000 VAC • Very Fast Acting • 15 – 1000 Amperes
Littelfuse LA100P semiconductor protection fuses are rated 1000V,
extending the range of protection for UPS systems, AC and DC drives,
reduced voltage motor starters and similar applications where lower I2t
and superior reliability are needed. With ratings from 15-1000 amperes,
a wide range of high voltage applications can be served.

Features
• Low I2t minimizes damage to protected components on short-circuit.
• Controlled arc voltage reduces stress to circuit components during
fuse clearing.

Applications
Protection of UPS systems, AC/DC drives, reduced voltage motor
starters and other 1000V or less semiconductor devices.

Ordering Information
LA 100 P 80 -4 TI
Littelfuse
Voltage
(1000)
Special Purpose Fuses

Style
Ampere Rating
Mounting Type
Ferrule
Blades/Bolt-in

1
4

Integral BlownFuse Indicator
Trigger Indicator

TI

Note: Mounting types and integral blown fuse indicators are optional for
specified ratings.

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:
Approvals:

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

AC: 1000 Volts
DC: 750 Volts
100,000 Amperes
15 – 1000 Amperes
UL Recognized under the components program.

99

Special Purpose Fuses

LA100P Semiconductor Fuses
1000 VAC • Very Fast Acting • 15 – 1000 Amperes

Catalog Numbers & Technical Data
Ampere
Rating

Special Purpose Fuses

15
20
25
30
35
40
50
50
60
60
70
80
80
100
100
125
125
150
150

Maximum
Littelfuse
Mounting
Watts Loss @
Clearing I2 t @1000
Catalog
Type
Rated Current (W)
Number
VAC (A 2S x 10 3 )
LA100P15-1
1
0.6
3.4
LA100P20-1
1
0.8
5.9
LA100P25-1
1
1,3
9
LA100P30-1
1
1.5
12.8
LA100P35-4
4
2.2
7.3
LA100P40-4
4
2.9
8.3
LA100P50-4
4
4.5
11
LA100P50-4TI
4TI
4.5
11
LA100P60-4
4
6.5
13
LA100P60-4TI
4TI
6.5
13
LA100P70-4TI
4TI
8.8
13
LA100P80-4
4
12
14
LA100P80-4TI
4TI
12
14
LA100P100-4
4
18
18
LA100P100-4TI
4TI
18
18
LA100P125-4
4
28
23
LA100P125-4TI
4TI
28
23
LA100P150-4
4
41
28
LA100P150-4TI
4TI
41
28

Ampere
Rating
200
200
225
250
300
300
350
350
400
400
500
500
600
600
650
700
800
800
1000

Figure 1

Figure 2

Figure 3

Figure 4

Maximum
Littelfuse
Mounting
Watts Loss @
Clearing I2 t @1000
Catalog
Type
Rated Current (W)
Number
VAC (A 2S x 10 3 )
LA100P200-4
4
72
36
LA100P200-4TI
4TI
72
36
LA100P225-4
4
91
40
LA100P250-4
4
110
46
LA100P300-4
4
160
55
LA100P300-4TI
4TI
160
55
LA100P350-4
4
220
65
LA100P350-4TI
4TI
220
65
LA100P400-4
4
290
70
LA100P400-4TI
4TI
290
70
LA100P500-4
4
450
90
LA100P500-4TI
4TI
450
90
LA100P600-4
4
650
110
LA100P600-4TI
4TI
650
110
LA100P650-4
4
780
120
LA100P700-4
4
880
125
LA100P800-4
4
1200
140
LA100P800-4TI
4TI
1200
140
LA100P1000-4
4
1900
190

Dimensions

Dimensions for reference only.

Amperes

Mount. Type

Fig. No.

15 – 30

1

1

35 – 60

4, 4TI

2

65 – 100

4, 4TI

2

125 – 200

4, 4TI

2

225 – 400

4, 4TI

2

500 – 600

4, 4TI

2

650 – 800

4, 4TI

3

1000

4

4

Dimensions in Inches (mm in parentheses)
A
2.53
(66.8)
5.00
(127)
5.00
(127)
5.72
(145)
5.72
(145)
7.72
(196)
7.44
(189)
8.22
(209)

B
0.56
(14.2)
1.00
(25.4)
1.22
(31)
2.00
(38.1)
2.00
(50.8)
2.50
(63.5)
2.88
(73.2)
3.50
(88.9)

C

D

E

F

G

H

J

–

–

–

–

–

–

–

3.50
(173)
3.50
(173)
3.47
(88.1)
3.47
(88.1)
3.47
(88.1)
3.94
(100)
4.47
(114)

4.31
(109)
4.31
(109)
4.78
(121)
4.78
(121)
5.88
(149)
5.94
(151)
6.59
(167)

4.19
(106)
4.19
(106)
4.16
(106)
4.16
(106)
5.56
(147)

0.31
(7.9)
0.31
(7.9)
0.41
(10.4)
0.41
(10.4)
0.53
(13.5)
0.63
(16)
0.63
(16)

0.75
(19.1)
1.00
(25.4)
1.00
(25.4)
1.50
(25.4)
2.00
(50.8)
2.00
(50.8)
2.75
(69.9)

0.13
(3.3)
0.19
(4.8)
0.25
(6.4)
0.25
(6.4)
0.38
(9.7)
0.38
(9.7)
0.50
(12.7)

–

5.84
(148)

–
–
–
–
–

0.31
(7.9)
1.38
(35.1)

Contact Littelfuse for characteristic curves.

100

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LA120X Semiconductor Fuses
1200 VAC • Very Fast Acting • 1/2 – 30 Amperes
Littelfuse LA120X semiconductor protection fuses, rated 1/ 2 through
30A, 1200 VAC are popular for use in traction drive auxiliary circuits and
similar applications. LA120X fuses are also suitable for use on 1000VDC
auxiliary circuits with low time constants.

Features
• 1000 Volt DC rating for a wide range of circuits.
• Compact size fits in where competitive sizes will not fit.

Applications
Protection of traction drive auxiliary circuits, etc.

Dimensions
In Inches (mm in parentheses)

4 5/8
(117)

.812
(20.6)

Special Purpose Fuses

Ordering Information
LA 120 X 25 -1
Littelfuse
Voltage
(1200)

Style

Catalog Numbers & Technical Data

Ampere Rating

Ampere
Rating

Littelfuse Catalog
Number

Mounting Type

Maximum Clearing I2 t
@1200 VAC (A 2S)

12

LA120A1/2-1
LA120X1-1
LA120X2-1
LA120X3-1
LA120X4-1
LA120X5-1
LA120X6-1
LA120X10-1
LA120X15-1
LA120X20-1
LA120X25-1
LA120X30-1

1
1
1
1
1
1
1
1
1
1
1
1

1.9
7.5
30
69
120
190
280
970
2100
3700
5700
8300

⁄
1
2
3
4
5
6
10
15
20
25
30

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Mounting Type
Ferrule

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Range:

AC: 1200 Volts
DC: 1000 Volts
100,000 Amperes
1
⁄ 2 – 30 Amperes

Note: Mounting type 1 can use 109002 and 129002 clips.

www.littelfuse.com

101

Special Purpose Fuses

Square Body Semiconductor Fuses
700/1300 VAC • Very Fast Acting • 40 – 2500 Amperes
Littelfuse North American style square body semiconductor fuses
provide maximum flexibility in equipment design and ultimate protection
for today’s power conversion equipment. Available in different body
sizes and multiple mounting styles, the broad range of ampere ratings
allows great flexibility in equipment design.
Engineered to provide state-of-the-art protection for SCR’s, diodes,
thyristors, GTO’s, and IGBT devices, Littelfuse square body fuses have
pure die-cut elements embedded in solidified sand to control arcing and
lower I2t. All fuses are also equipped with a blown fuse trip indicator.

Features
• Choice of mounting styles provides a wide choice for equipment
design.
• Broad range of ampere ratings in a given body size for design
flexibility.
• Very low I2t minimizes damage to protected components.
• Superior cycling ability for long, reliable life on high cyclic loading.
• Extremely fast acting and current-limiting for improved protection to
equipment.

Applications
Special Purpose Fuses

Ordering Information

Protection of rectifiers, inverters, DC drives, UPS systems, reduced
voltage motor starters, and other equipment in globally accepted
applications.

LA 070 URD 31 LI 350

Specifications

Littelfuse

Voltage Rating:

Voltage
(070=700V
130=1300V)

Interrupting Rating:

Class
Ampere Range:
Approvals:

Size
700V
30
31
32
33

1300V
70
71
72
73

AC: 700 Volts (LA070)
1300 Volts (LA130)
DC: Contact factory
AC:
200,000 Amperes (LA070)
100,000 Amperes (LA130)
DC: Contact factory
40 – 2500 Amperes
UL Recognized Component

Mounting Type
Straight-blade
Straight-blade
Flat-type, one hole

KI
LI
TTI

LI
LLI
TTI

Amp Rating

102

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

Square Body Semiconductor Fuses
700/1300 VAC • Very Fast-Acting • 40 – 2500 Amperes
700 Volt North American Style Ratings and Application Data
Body Size

30

31

33

Rated
Voltage

Melting I2 t
(A 2S x 10 3 )

Total I2 t
@ Rated
Voltage
(A 2S x 10 3 )

**Watts
Loss @ Rated
Current
(W)

Long Blade
Catalog No.
Type LI

Short Blade
Catalog No.
Type KI

Tapped Terminal
Catalog No.
Type TTI

63
80
100
125
160
200
250
315
350
400
450
500
550
200
250
315
350
400
450
500
550
630
700
800
400
450
500
550
630
700
800
900
1000
1100
1250
1400
1600
1800
500
550
630
700
800
900
1000
1100
1250
1400
1600
1800
2000
2250
2500

700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
700
650
600
550
550
500
700
700
700
700
700
700
700
700
700
700
650
650
600
550
500

0.2
0.33
0.47
0.85
1.6
3
5.8
12
15.5
23
26
41
52
2.5
4.7
7.5
10.5
19
26.5
37
52
75
95
140
15
22
28
37
54
76
115
170
240
270
410
555
870
1050
19
27
40
55
95
135
170
240
350
480
555
720
950
1250
1870

1.2
1.9
2.7
4.9
9.2
16.7
32.4
67
86
130
165
264
330
14.6
27
43
59
110
150
210
300
421
530
880
86
124
157
211
302
432
648
972
1350
1620
2100
2600
4000
4400
108
151
227
324
529
760
970
1360
2000
2700
3250
4330
5000
5900
7600

14
19
26
30
37
42 ⁄ 43
48 ⁄ 50
53 ⁄ 55
57 ⁄ 60
60 ⁄ 65
80 ⁄ 88
80 ⁄ 88
80 ⁄ 90
45
52
65
67
68
70
70 ⁄ 72
70 ⁄ 75
75 ⁄ 85
85 ⁄ 95
105 ⁄ 120
72 ⁄ 75
77 ⁄ 80
85 ⁄ 90
90 ⁄ 95
95 ⁄ 105
100 ⁄ 110
110 ⁄ 120
110 ⁄ 125
115 ⁄ 135
140 ⁄ 165
150 ⁄ 180
160 ⁄ 190
165 ⁄ 195
195 ⁄ 330
105
105 ⁄ 110
110 ⁄ 120
115 ⁄ 125
120 ⁄ 130
120 ⁄ 135
135 ⁄ 155
135 ⁄ 160
150 ⁄ 180
160 ⁄ 200
210 ⁄ 240
225 ⁄ 260
250 ⁄ 290
280 ⁄ 330
280 ⁄ 330

LA070URD30LI0063
LA070URD30LI0080
LA070URD30LI0100
LA070URD30LI0125
LA070URD30LI0160
LA070URD30LI0200
LA070URD30LI0250
LA070URD30LI0315
LA070URD30LI0350
LA070URD30LI0400
LA070URD30LI0450
LA070URD30LI0500
LA070URD30LI0550
LA070URD31LI0200
LA070URD31LI0250
LA070URD31LI0315
LA070URD31LI0350
LA070URD31LI0400
LA070URD31LI0450
LA070URD31LI0500
LA070URD31LI0550
LA070URD31LI0630
LA070URD31LI0700
LA070URD31LI0800
LA070URD32LI0400
LA070URD32LI0450
LA070URD32LI0500
LA070URD32LI0550
LA070URD32LI0630
LA070URD32LI0700
LA070URD32LI0800
LA070URD32LI0900
LA070URD32LI1000
LA065URD32LI1100
LA060URD32LI1250
LA055URD32LI1400
LA055URD32LI1600
LA050URD32LI1800
LA070URD33LI0500
LA070URD33LI0550
LA070URD33LI0630
LA070URD33LI0700
LA070URD33LI0800
LA070URD33LI0900
LA070URD33LI1000
LA070URD33LI1100
LA070URD33LI1250
LA070URD33LI1400
LA065URD33LI1600
LA065URD33LI1800
LA060URD33LI2000
LA050URD33LI2250
LA050URD33LI2500

LA070URD30KI0063
LA070URD30KI0080
LA070URD30KI0100
LA070URD30KI0125
LA070URD30KI0160
LA070URD30KI0200
LA070URD30KI0250
LA070URD30KI0315
LA070URD30KI0350
LA070URD30KI0400
LA070URD30KI0450
LA070URD30KI0500
LA070URD30KI0550
LA070URD31KI0200
LA070URD31KI0250
LA070URD31KI0315
LA070URD31KI0350
LA070URD31KI0400
LA070URD31KI0450
LA070URD31KI0500
LA070URD31KI0550
LA070URD31KI0630
LA070URD31KI0700
LA070URD31KI0800
LA070URD32KI0400
LA070URD32KI0450
LA070URD32KI0500
LA070URD32KI0550
LA070URD32KI0630
LA070URD32KI0700
LA070URD32KI0800
LA070URD32KI0900
LA070URD32KI1000
–
–
–
–
–
LA070URD33KI0500
LA070URD33KI0550
LA070URD33KI0630
LA070URD33KI0700
LA070URD33KI0800
LA070URD33KI0900
LA070URD33KI1000
LA070URD33KI1100
LA070URD33KI1250
LA070URD33KI1400
–
–
–
–
–

LA070URD30TTI0063
LA070URD30TTI0080
LA070URD30TTI0100
LA070URD30TTI0125
LA070URD30TTI0160
LA070URD30TTI0200
LA070URD30TTI0250
LA070URD30TTI0315
LA070URD30TTI0350
LA070URD30TTI0400
LA070URD30TTI0450
LA070URD30TTI0500
LA070URD30TTI0550
LA070URD31TTI0200
LA070URD31TTI0250
LA070URD31TTI0315
LA070URD31TTI0350
LA070URD31TTI0400
LA070URD31TTI0450
LA070URD31TTI0500
LA070URD31TTI0550
LA070URD31TTI0630
LA070URD31TTI0700
LA070URD31TTI0800
LA070URD32TTI0400
LA070URD32TTI0450
LA070URD32TTI0500
LA070URD32TTI0550
LA070URD32TTI0630
LA070URD32TTI0700
LA070URD32TTI0800
LA070URD32TTI0900
LA070URD32TTI1000
LA065URD32TTI1100
LA060URD32TTI1250
LA055URD32TTI1400
LA055URD32TTI1600
LA050URD32TTI1800
LA070URD33TTI0500
LA070URD33TTI0550
LA070URD33TTI0630
LA070URD33TTI0700
LA070URD33TTI0800
LA070URD33TTI0900
LA070URD33TTI1000
LA070URD33TTI1100
LA070URD33TTI1250
LA070URD33TTI1400
LA065URD33TTI1600
LA065URD33TTI1800
LA060URD33TTI2000
LA055URD33TTI2250
LA050URD33TTI2500

Special Purpose Fuses

32

Amp
Rating

** Watts loss data is published for both blade and tapped style mounting configurations.
When two watts loss values are shown, this represents tapped/blade values respectively.
Contact Littelfuse for characteristic curves.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

103

Special Purpose Fuses

Square Body Semiconductor Fuses
700/1300 VAC • Very Fast Acting • 40 – 2500 Amperes
North American Straight Blade, Type KI

Dimensions - 700V Fuses

TYPES KI AND LI

Catalog Number
J
C

B

LA070URD30KI (63-550)
LA070URD31KI (200-800)

1.925 MAX
[47.6]

LA070URD32KI (400-1000)

F
G

LA070URD33KI (500-1400)

H

A

Dimensions for reference only.
Dimensions in Inches (mm in parentheses)

A
1.57
(40)
2.01
(51)
2.36
(60)
2.93
(74.5)

B
0.98
(25)
0.98
(25)
1.26
(32)
1.57
(40)

C
0.49
(12.5)
0.49
(12.5)
0.63
(16)
0.79
(20)

D
0.83
(21)
1.0
(25.5)
1.18
(30)
1.46
(37.2)

E
0.71
(18)
0.89
(22.5)
1.06
(27)
1.35
(34.2)

F
2.68
(68)
2.66
(67.6)
2.92
(74.2)
2.97
(75.4)

G
H
4.21
5.08
(107)
(129)
4.22
5.07
(107.1) (128.8)
4.29
5.28
(109)
(134)
4.24
5.28
(107.6) (134)

J
0.41
(10.5)
0.56
(14.3)
0.57
(14.6)
0.63
(15.9)

North American Straight Blade Types LI

D

.24
[6]

E

Dimensions - 700V Fuses

Dimensions for reference only.

A

Catalog Number
LA070URD30LI (63-550)
Special Purpose Fuses

LA070URD31LI (200-800)
LA070URD32LI (400-1000)
LA065URD32LI (1250)
LA055URD32LI (1400-1600)
LA050URD32LI (1800)
LA070URD33LI (500-1400)
LA065URD33LI (1600-1800)
LA060URD33LI (2000)
LA055URD33LI (2250)
LA050URD33LI (2500)

TYPE TTI
C

Dimensions in Inches (mm in parentheses)
A
1.57
(40)
2.01
(51)

B
0.98
(25)
0.98
(25)

C
0.49
(12.5)
0.49
(12.5)

D
0.83
(21)
1.0
(25.5)

E
0.71
(18)
0.89
(22.5)

F
3.45
(87.6)
3.61
(91.6)

G
H
4.98
5.85
(126.6) (148.6)
4.82
5.85
(122.4) (148.6)

J
0.41
(10.5)
0.57
(14.6)

2.36
(60)

1.26
(32)

0.63
(16)

1.18
(30)

1.06
(27)

3.71
(94.2)

5.08
(129)

6.02
(153)

0.57
(14.6)

2.93
(74.5)

1.57
(40)

0.79
(20)

1.46
(37.2)

1.35
(34.2)

3.72
(94.4)

4.98
(126.6)

6.02
(153)

0.63
(15.9)

.26
[6.7]

B

A

North American Flat Single Hole, Type TTI

Dimensions - 700V Fuses
A

Catalog Number
LA070URD30TTI (100-550)
LA070URD31TTI (200-800)

1.93 MAX
[49]
2
[50.6]

104

LA070URD32TTI (400-1000)
LA065URD32TTI (1100)
LA060URD32TTI (1250)
LA055URD32TTI (1400-1600)
LA060URD33TTI (1800)
LA070URD33TTI (500-1400)
LA065URD33TTI (1600)
LA060URD33TTI (2000)
LA055URD33TTI (2250)
LA050URD33TTI (2500)

www.littelfuse.com

Dimensions for reference only.)
Dimensions in Inches (mm in parentheses)
A
1.57
(40)
2.00
(50.8)

B
1.00
(25)
1.19
(30.2)

C

2.37
(60.3)

1.50
(38.1)

3 8

2.94
(74.5)

1.81
(46)

12

5 16

⁄ -18 x 0.35

5 16

⁄ -18 x 0.35

⁄ -16 x 0.35

⁄ -18 x 0.35

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

Square Body Semiconductor Fuses
700/1300 VAC • Very Fast Acting • 40 – 2500 Amperes
1300 Volt North American Style Ratings and Application Data
Body
Size

70

71

73

63
80
100
125
160
200
250
315
350
160
200
250
280
315
350
400
450
500
550
630
630
280
315
350
400
450
500
550
630
630
700
700
800
800
315
350
400
450
500
550
630
700
800
800
900
900
1000
1100
1250
1400
1600
1800

1300
1300
1300
1300
1300
1300
1300
1300
1200
1300
1300
1300
1300
1300
1300
1300
1300
1200
1200
1100
1200
1300
1300
1300
1300
1300
1300
1300
1200
1300
1100
1200
1100
1200
1300
1300
1300
1300
1300
1300
1300
1300
1200
1300
1100
1300
1100
1000
1000
900
700
660

Melting I2 t
(A 2S x 10 3 )
0.21
0.47
0.83
1.3
2.5
4.7
9.6
20
28
2.6
4.7
8.9
12
16
22
38
47
68
84
125
125
10
15
21
32
44
57
68
105
105
145
145
215
215
12
17
25
35
44
57
84
110
190
190
250
250
370
445
585
755
1430
2040

Total I2 t @
**Watts Loss @
Rated Voltage
Rated Current (W)
2
3
(A S x 10 )
1.8
4
7.2
11
22
40
82
172
205
22
40
76
102
138
190
330
405
500
620
930
930
90
130
180
285
380
500
590
920
920
1040
1040
1590
1590
102
150
220
310
390
500
730
960
1630
1630
2160
2160
2430
2580
3480
3880
5630
7600

26
27
30
38
45
54 ⁄ 56
58 ⁄ 61
66 ⁄ 72
68 ⁄ 75
46
54
61
68 ⁄ 70
73 ⁄ 76
76 ⁄ 80
76 ⁄ 80
87 ⁄ 95
90 ⁄ 100
98 ⁄ 112
105
120
72
76
77
80
87 ⁄ 89
94 ⁄ 98
110 ⁄ 120
113
125
122
140
125
146
84
86
93
99 ⁄ 100
110 ⁄ 112
116 ⁄ 120
125 ⁄ 132
135 ⁄ 146
136
148
150
170
152 ⁄ 174
168 ⁄ 208
186 ⁄ 200
210 ⁄ 228
203
206

Long Blade
Catalog No. Type LI/LLI

Tapped Terminal
Catalog No. Type TTI

LA130URD70LI0063
LA130URD70LI0080
LA130URD70LI0100
LA130URD70LI0125
LA130URD70LI0160
LA130URD70LI0200
LA130URD70LI0250
LA130URD70LI0315
LA120URD70LI0350
LA130URD71IL0160
LA130URD71LLI0200
LA130URD71LLI0250
LA130URD71IL0280
LA130URD71LLI0315
LA130URD71LLI0350
LA130URD71LLI0400
LA130URD71LLI0450
LA120URD71LLI0500
LA120URD71LLI0550
LA110URD71LLI0630
–
LA130URD72LI0280
LA130URD72LI0315
LA130URD72LI0350
LA130URD72LI0400
LA130URD72LI0450
LA130URD72LI0500
LA130URD72LI0550
LA120URD72LI0630
–
LA110URD72LI0700
–
LA110URD72LI0800
–
LA130URD73LI0315
LA130URD73LI0350
LA130URD73LI0400
LA130URD73LI0450
LA130URD73LI0500
LA130URD73LI0550
LA130URD73LI0630
LA130URD73LI0700
LA120URD73LI0800
–
LA110URD73LI0900
–
LA100URD73LI1000
LA100URD73LI1100
LA100URD73LI1250
LA090URD73LI1400
LA070URD73LI1600
LA065URD73LI1800

LA130URD70TTI0063
LA130URD70TTI0080
LA130URD70TTI0100
LA130URD70TTI0125
LA130URD70TTI0160
LA130URD70TTI0200
LA130URD70TTI0250
LA130URD70TTI0315
LA120URD70TTI0350
LA130URDT1TTI0160
LA130URD71TTI0200
LA130URD71TTI0250
LA130URD71TTI0280
LA130URD71TTI0315
LA130URD71TTI0350
LA130URD71TTI0400
LA130URD71TTI0450
LA120URD71TTI0500
LA120URD71TTI0550
–
LA120URD71TTI0630
LA130URD72TTI0280
LA130URD72TTI0315
LA130URD72TTI0350
LA130URD72TTI0400
LA130URD72TTI0450
LA130URD72TTI0500
LA130URD72TTI0550
–
LA130URD72TTI0630
LA120URD72TTI0700
–
LA120URD72TTI0800
LA130URD73TTI0315
LA130URD73TTI0350
LA130URD73TTI0400
LA130URD73TTI0450
LA130URD73TTI0500
LA130URD73TTI0550
LA130URD73TTI0630
LA130URD73TTI0700
–
LA130URD73TTI0800
–
LA130URD73TTI0900
LA100URD73TTI1000
LA100URD73TTI1100
LA100URD73TTI1250
LA090URD73TTI1400
LA070URD73TTI1600
LA065URD73TTI1800

Special Purpose Fuses

72

Amp Rating Rated Voltage

** Watts loss data is published for both blade and tapped style mounting configurations.
When two watts loss values are shown, this represents tapped/blade values respectively.
Contact Littelfuse for characteristic curves.
© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

105

Special Purpose Fuses

Square Body Semiconductor Fuses
700/1300 VAC • Very Fast Acting • 40 – 2500 Amperes
TYPES LI AND LLI

A

J
C

B
D

2.85
[72.5]

E

F

A

0.2
[5.03]

G
H

North American Straight Blade, Types LI and LLI

Dimensions - 1300V Fuses
Catalog Number

Special Purpose Fuses

LA130URD70LI (63-315)
LA120URD70LI (350)
LA130URD71LLI (160-450)
LA120URD71LLI (500-550)
LA110URD71LLI (630)
LA130URD72LI (280-550)
LA120URD72LI (800)
LA110URD72LI (700-800)
LA130URD73LI (315-700)
LA120URD73LI (800)
LA110URD73LI (900-1000)
LA090URD73LI (1400)
LA070URD73LI (1600)
LA065URD73LI (1800)

Dimensions for reference only.
Dimensions In Inches (mm in parentheses)

A
1.57
(40)

B
0.98
(25)

C
0.49
(12.5)

D
0.83
(21)

E
0.71
(18)

F
3.60
(91.4)

G
5.13
(130.4)

H
6.00
(152.4)

J
0.41
(10.5)

2.01
(51)

0.98
(25)

0.49
(12.5)

1.0
(26.5)

0.89
(22.5)

3.60
(91.4)

5.13
(130.4)

6.00
(152.4)

0.57
(14.6)

2.36
(60)

1.26
(32)

0.63
(16)

1.18
(30)

1.06
(27)

3.84
(97.6)

5.2
(132.4)

6.20
(157.4)

0.57
(14.6)

2.93
(74.5)

1.57
(40)

0.79
(20)

1.46
(37.2)

1.35
(34.2)

3.89
(98.8)

5.21
(132.4)

6.20
(157.4)

0.63
(15.9)

North American Flat Single Hole, Type TTI

Dimensions - 1300V Fuses

TYPE TTI
C

Catalog Number
A

2.91
[74]

106

2.85 MAX
[72.5]
0.2
[5.03]

B
A

LA130URD70TTI (63-315)
LA120URD70TTI (350)
LA130URD71TTI (160-450)
LA120URD71TTI (550-630)
LA130URD72TTI (280-630)
LA120URD72TTI (700-800)
LA130URD73TTI (315-900)
LA120URD73TTI (1000)
LA110URD73TTI (1250)
LA090URD73TTI (1400)
LA070URD73TTI (1600)
LA065URD73TTI (1800)

www.littelfuse.com

Dimensions for reference only.

Dimensions in Inches (mm)
A
B
C
1.57
1.00
5 16
⁄ -18 x 0.23 DP
(40)
(26.4)
2.01
1.19
5 16
⁄ -18 x 0.36 DP
(51)
(30.2)
2.36
1.50
38
⁄ -18 x 0.36 DP
(60)
(38.1)

2.93
(74.5)

1.81
(46)

12

⁄ -18 x 0.36 DP

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

Fork-Lift and Stud-Mounted Fuses
32 – 130 Volts DC • Fast Acting and Time-Delay
CNL/CNN Limiter Fuses

Specifications
Voltage Ratings:

CNL: 32 Volts DC
CNN: 48 Volts DC, 75 Volts AC
2,500 amperes
10 – 800 amperes
90 Inch lbs.

Interrupting Rating:
Ampere Range:
Maximum Torque:

Recommended Fuse Block
LFFB001

Ampere ratings
CNL fast-acting and CNN very fast acting fuses are recommended for
use on battery operated lift trucks and other low voltage battery operated
equipment.

CNL

35
40
50
60

80
100
125
130

150
175
200
225

250
275
300
325

350
400
500

CNN

10
35
40
50
60

80
90
100
125
150

175
200
225
250
275

300
325
350
400

500
600
700
800

2.43"

0.343"
3.18"

Example part number (series & amperage): CNN 700
Special Purpose Fuses

CBO/CCK/CCL Lift-Truck Fuses
CBO fast acting, and CCK and CCL dual-element time-delay fuses are recommended for fork lift trucks and other similar battery operated equipment.

Specifications
Voltage Ratings:

Part No.
CCK 1-15A
CCK 20-30A
CCK 35-60A
CCK 70-120A
CCK 140-200A
CCK 225-300A
CCL 30-60A
CCL 80-120A

A
2.810
3.060
3.629
4.129
4.362
4.612
3.060
3.38

A

B
2.204
2.454

C
0.510
0.510
0.750
1.00
1.00
1.00
0.51
0.75

3.454
3.579
3.829
2.454
2.70
1.625"

CBO: 32 Volts DC
CCK: 130 Volts DC (1-100A)
72 Volts DC (120-200A)
48 Volts DC (225-300A)
CCL: 125 Volts DC
Interrupting Rating:
CBO, CCK & CCL: 10,000A
Ampere Range:
1 – 300 amperes
For operating characteristics contact factory

Ampere ratings
CBO
Fast Acting

CCK
Time-Delay

B
0.812"

C

CCL
Time-Delay

10
12
15
20
1
2
10
15
20
30
35

25
30
35
40
25
30
35
40
50
40
50

50
60
70
75
60
70
75
80
100
60
80

80
100
125
150
120
140
150
160
175
100
120

200
225
250
300

1.00"

Example part number (series & amperage): CCK 150
CCK/CCL
© 2005 Littelfuse • POWR-GARD™ Products Catalog

CBO

www.littelfuse.com

107

Special Purpose Fuses

Cable Limiters
600 Volts AC
Cable limiters are fusible devices that provide very fast short-circuit
protection, primarily to faulted cables, but also to other conductors such
as busway. Cable limiters do not have an ampere rating, and cannot be
used to provide overload protection. They are instead selected by cable
size; for example, a 500 kcmil cable requires a 500 kcmil cable limiter.
Their main use is to isolate faulted cables in circuits containing three or
more parallel conductors per phase. They may be installed on the line
side of the main service to provide short-circuit protection to the service
conductors. This is especially important when service conductors are
tapped from large low voltage networks or from large low impedance
transformers.
Cable limiters have terminals which permit them to be installed in a
variety of equipment. The most common configuration is the offset
blade on one end and the crimp terminal on the other end. This permits
the limiter to replace a cable terminal (lug).

Applications
Service entrance conductors
Between transformer or network bus and busway terminal boxes
Large feeders with three or more conductors per phase

Special Purpose Fuses

Features

Description
Type

Termination

1
Cable to Cable

3
Cable to Offset
Bus

5
Straight Bus to
Offset Bus

6
Mole to Cable

8
Mole to Offset
Bus

108

Catalog Number
Cable Size
4/0
250MCM
350MCM
500MCM
750MCM
4/0
250MCM
350MCM
500MCM
750MCM
4/0
250MCM
350MCM
500MCM
750MCM
4/0
250MCM
350MCM
500MCM
750MCM
4/0
250MCM
350MCM
500MCM
750MCM

Cable Type
Copper
Aluminum
LFCL4/0C1
LFCL4/0A1
LFCL250C1
LFCL250A1
LFCL350C1
LFCL350A1
LFCL500C1
LFCL500A1
LFCL750C1
LFCL750A1
LFCL4/0C3
LFCL4/0A3
LFCL250C3
LFCL250A3
LFCL350C3
LFCL350A3
LFCL500C3
LFCL500A3
LFCL750C3
LFCL750A3
LFCL4/0C5
–
LFCL250C5
–
LFCL350C5
–
LFCL500C5
–
LFCL750C5
–
LFCL4/0C6
LFCL4/0A6
LFCL250C6
LFCL250A6
LFCL350C6
LFCL350A6
LFCL500C6
LFCL500A6
LFCL750C6
LFCL750A6
LFCL4/0C8
–
LFCL250C8
–
LFCL350C8
–
LFCL500C8
–
LFCL750C8
–

• Current-limiting characteristics provide protection to conductor
insulation and reduce damage when faults occur.
• Properly applied cable limiters may permit the use of equipment with
reduced withstand ratings
• Wide variety of terminations and cable ratings permit use in almost
every situation.

Specifications
Voltage Rating:
Interrupting Rating:
Cable Size Range:

600 volts AC
200,000 Amperes
4⁄ 0 – 750MCM Copper or Aluminum

Note: For Type 5 and Type 8 Aluminum cable limiters, use the Copper Type C5
and C8.

Ordering Information

LFCL - 500 - C - 1
Littelfuse
Cable Limiter
Conductor Size
Terminal Material
(Aluminum or Copper)

Type of
Termination

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Special Purpose Fuses

LGR/ LMF In-Line Fuses and LHR Holder

Specifications

LGR Fuses
Fast Acting • 300 VAC
Used as in-line protection for
fluorescent fixtures, this fast
acting fuse is ideal for increasing
the safety and reliability of lighting
fixtures.

Voltage Rating:
Maximum Interrupting Rating:
Approvals:

300 volts AC
10,000A
Standard 248-14,
UL Listed (File No: E10480)
CSA Certified (File No: LR29862)

Ampere Ratings
12

⁄

0.610"

1
1 1⁄2
1.82"

1 6 ⁄10
2
2 1⁄2

3
4
5

6
7
8

9
10
12

15

Example part number (series & amperage): LGR 1 1⁄2

Specifications

LMF Fuses
Time-Delay • 300 VAC
Perfect for use in lighting systems,
this 300 VAC time-delay fuse
is designed to handle ballast
transformer in-rush currents.

Voltage Rating:
Maximum In terrupting Rating:
Approvals:

300 volts AC
10,000A
Standard 248-14,
UL Listed (File No: E10480)
CSA Certified (File No: LR29862)

3 10

8 10

12

1
1 1⁄4

⁄
⁄
6 10
⁄

0.610"

⁄

1 6 ⁄10
2
2 1⁄2

2 8 ⁄10
3
3 2 ⁄10

4
5
6 1⁄4

Special Purpose Fuses

Ampere Ratings
7
8
10

1.82"

Example part number (series & amperage): LMF 2 1⁄2

LHR Fuse Holder

Specifications

Used as in-line protection for
fluorescent fixtures, the Littelfuse
LGR and LMF series fuses and LHR
holder offer increased safety and
reliability to lighting systems. On a
277 volt system, a fault occurring
in an unfused fixture could take out
the entire branch circuit affecting
as many as 100 fixtures. This could
cause safety problems as well as
shut down operations.

Voltage Rating:
Ampere Rating:

7/8"

By individually fusing fixtures, these
problems will be avoided. The
added benefits of this is the ability to quickly identify the problem fixture
and reduce the repair time.

Approvals:
Flammability Rating:
Example part number:

300 volts AC
LHR 000: 10A
LHR 001: 10A
UL Recognized
94VO
LHR 000

3/4"

Knock-out Hole

Mounting Information

0.263"

LHR 001/LHR 000 will fit keyhole punch or
0.875" knock-out hole. Anti-rotation feature is
provided when used with keyhole punch.

0.630"
0.423"

A “U-shaped” clip is available for panel mounting (packaged 10 clips per bag): Order part
number LHR OCA.

Keyhole Punch

2.25"

Fuse holders are rated up to 10 amperes at 300 volts and are equipped
with 7" 18 AWG leads. Order part number LHR 000 for two leads, and
part number LHR 001 for one lead with the other terminal used for
insertion of 18 AWG ballast lead.

0.50"
0.50"

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

109

Blocks and Holders

Fuse Blocks

111

Class H/K5 and R Fuse Blocks

112-116

Class J Fuse Blocks

117-119

Class T Fuse Blocks

120-123

Class G Fuse Blocks

124

Class CC/CD and Midget Fuse Blocks

125-126

Class CC and Midget Fuse Block Accessories

127

Fuse Block, Holders and Accessories

128-133

Semiconductor Fuse Blocks

134-136

POWR-BLOKS™ Distribution/Splicer Blocks

137-144

In-Line Watertight Fuseholders

145-150

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Fuse Blocks
General Information
4. Determine if NEC, CSA, UL, or other requirements
are applicable
If fuse blocks will be installed in equipment to be submitted for agency
approval, the requirements should be obtained from the approving
agency in advance of fuse and fuse block selection.

5. Select the type of wire termination
A choice of three types of wire termination is available:
a) Screw* — for use with spade lugs or ring terminals.
b) Screw with Pressure Plate* — for use with solid or stranded wire
without terminal. Recommended where vibration will be a factor.
c) Box Lug — the most durable. For use with all types of solid wire and
Class B and Class C stranded wire. Not for use with welding cable or
other rope-stranded conductors.
* 1 / 4” Quick Connect terminals rated for up to 20A are
available on the Midget and Class CC fuse blocks.

Fuse Block Selection
The following guidelines should help simplify the selection of proper
fuse blocks:

Screw
with
Pressure
Plate
(P)

1. Determine the system voltage
Since fuses are selected on the basis of system voltage, fuse blocks are
selected to match the voltage rating of the fuse.

Screw
(S)

Box
Lug
(C)

6. Decide on the number of poles in each block
2. Determine the design short-circuit current

Class H fuse blocks will accept Class H or K5 fuses (which have an
interrupting rating of up to 50,000 amperes) and Class R fuses (which
have a 200,000 A.I.R.). To prevent the possibility of inserting a fuse
with the incorrect interrupting rating, the use of Class R fuse blocks is
recommended for use with Class R fuses. Use Class H fuse blocks with
Class H or K5 fuses. These fuse blocks are dimensionally the same, but
the Class R fuse blocks incorporate a rejection feature which allows only
Class R fuses to be inserted.

The number of poles for each set of fuses is determined by the
characteristics of the circuit. The option to gang individual fuse blocks
into long strips will be determined by the available space and by the
type of wire being used.

Blocks and Holders

Available and/or design short-circuit current is an important
consideration when determining the class of fuse and fuse blocks to
use. If available short-circuit current cannot be determined, or if it will
vary with equipment location, select fuses with a 200,000 ampere
interrupting rating (A.I.R.) and mating fuse blocks with a withstand rating
of 200,000 amperes for maximum safety.

7. Determine if fuse clips need to be reinforced
Fuse clips may have a tendency to lose some of their tension over a
period of time. This may be prevented by specifying reinforced fuse
clips. Reinforced clips are standard on certain fuse blocks (see individual
product pages).

Ordering Information
The Littelfuse fuse block part number consists of 6 or 7 components, as
shown below and in the individual fuse block data tables.

3. Determine the type and ampere rating of the fuse to be used
In addition to voltage and interrupting rating as discussed above, the
fuse ampere rating, opening characteristics (fast acting or time-delay)
and size are other important considerations in fuse selection. Once the
fuse type is selected, the mating fuse block can be chosen. Fuse blocks
are available in 30, 60, 100, 200, 400 and 600 amp ratings, and may be
used with a fuse rated at the corresponding amperage rating or below.
For example, a fuse block rated at 30 amperes may be used with a fuse
rated from 0 to 30 amperes.

For all Class R, H, J, T and 15, 20
& 60A Class G Fuse Blocks

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

For all Class CC, Midget and 30A
Class G Fuse Blocks

111

Blocks and Holders

Class H/K5 and R Fuse Blocks
250 and 600 Volt

Features/Benefits
• Class H and Class R fuse blocks feature clip designs to maximize
electrical contact and minimize heat rise.
• Reinforcing clips are standard on all Class H fuse blocks rated 100
amp and higher. Note: For reinforcing clips on Class H blocks rated 30-60

amp, add “R” suffix to connector type.
• Reinforcing clips are standard on all Class R fuse blocks

Specifications
Voltage Rating:
Ampere Ratings:
Approvals:

250 Volts; 600 Volts
0 – 600 amperes
UL Listed (File No. E14721)
CSA Certified (File No. LR73091)

Recommended Fuses
Class H Blocks
250V
600V
NLN
NLS
RLN
RLS

Class H and Class R fuse blocks are dimensionally the same, but Class R blocks
incorporate a rejection feature, which only allows Class R fuses to be inserted.

Note: For optional fuse block covers, refer to POWR-Covers section of this catalog.

Class H 250V

Class H 600V

Amp No. of
Rating Poles

Blocks and Holders

30
60
100
200
400
600

1
2
3
1
2
3
1
2
3
1
3
1
3
1
3

Catalog
Number
LH25030-1
LH25030-2
LH25030-3
LH25060-1
LH25060-2
LH25060-3
LH25100-1
LH25100-2
LH25100-3
LH25200-1
LH25200-3
LH25400-1
LH25400-3
LH25600-1
LH25600-3

Connector Type
(Add Suffix Shown)
Pressure
Box
Screw
Plate
Lug
S (R)
P (R)
C (R)
S (R)
P (R)
C (R)
S (R)
P (R)
C (R)
S (R)
C (R)
S (R)
C (R)
S (R)
C (R)
C
C
C
C
C
CR
CR
C
C

Maximum Wire
Size

Amp No. of
Rating Poles

S & P = #10 CU
C = #6 CU-AL

30

S = #10 CU
C = #2 CU-AL

60

# 2/0 CU-AL

100

250 MCM CU-AL

200

(2) 350 MCM CU-AL

400

(2) 500 MCM CU-AL

600

1
2
3
1
2
3
1
2
3
1
3
1
3
1
3

Catalog
Number
LH60030-1
LH60030-2
LH60030-3
LH60060-1
LH60060-2
LH60060-3
LH60100-1
LH60100-2
LH60100-3
LH60200-1
LH60200-3
LH60400-1
LH60400-3
LH60600-1
LH60600-3

Connector Type
(Add Suffix Shown)
Pressure
Box
Screw
Plate
Lug
S (R)
P (R)
C (R)
S (R)
P (R)
C (R)
S (R)
P (R)
C (R)
C (R)
C (R)
C (R)
C
C
C
C
C
CR
CR
C
C

Maximum Wire
Size
S & P = #10 CU
C = #6 CU-AL
S = #10 CU
C = #2 CU-AL
#2/0 CU-AL
250 MCM CU-AL
(2) 350 MCM CU-AL
(2) 500 MCM CU-AL

Note: Reinforcing springs standard on all Class H fuseblocks 100 amperes and above.

Note: Reinforcing springs standard on all Class H fuse blocks 100 amperes and above.

Class R 250V

Class R 600V

Amp No. of
Rating Poles
30
60
100
200
400
600

1
2
3
1
2
3
1
2
3
1
3
1
3
1
3

Catalog
Number
LR25030-1
LR25030-2
LR25030-3
LR25060-1
LR25060-2
LR25060-3
LR25100-1
LR25100-2
LR25100-3
LR25200-1
LR25200-3
LR25400-1
LR25400-3
LR25600-1
LR25600-3

Connector Type
(Add Suffix Shown)
Pressure
Box
Screw
Plate
Lug
SR
PR
CR
SR
PR
CR
SR
PR
CR
CR
CR
CR
C
C
C
C
C
CR
CR
C
C

Note: Reinforcing springs standard on all Class R fuse blocks.

112

Class R Blocks
250V
600V
FLNR/FLNR_ID
FLSR/FLSR_ID
KLNR
KLSR
LLNRK
LLSRK/LLSRK_ID
TLN
IDSR

Maximum Wire
Size

Amp No. of
Rating Poles

S & P = #10 CU
C = #6 CU-AL

30

S = #10 CU
C = #2 CU-AL

60

#2/0 CU-AL

100

250 MCM CU-AL

200

(2) 350 MCM CU-AL

400

(2) 500 MCM CU-AL

600

1
2
3
1
2
3
1
2
3
1
3
1
3
1
3

Catalog
Number
LR60030-1
LR60030-2
LR60030-3
LR60060-1
LR60060-2
LR60060-3
LR60100-1
LR60100-2
LR60100-3
LR60200-1
LR60200-3
LR60400-1
LR60400-3
LR60600-1
LR60600-3

Connector Type
(Add Suffix Shown)
Pressure
Box
Screw
Plate
Lug
SR
PR
CR
SR
PR
CR
SR
PR
CR
CR
CR
CR
C
C
C
C
C
CR
CR
C
C

Maximum Wire
Size
S & P = #10 CU
C = #6 CU-AL
S = #10 CU
C = #2 CU-AL
#2/0 CU-AL
250 MCM CU-AL
(2) 350 MCM CU-AL
(2) 500 MCM CU-AL

Note: Reinforcing springs standard on all Class R fuse blocks.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class H/K5 and R Fuse Blocks
250 Volt
250V 30A
1.91"

2.95"

[48.5]

[74.9]

.22/5.6 DIA. HOLE THRU
4 PLACES

1.25"
[31.8]

1.50"

1.50"

[38.1]

[38.1]

3.00"
[76.2]

.50"
[13]

.75"

.19"

[19]

[4.8]

.33"

.53"

.22"

[8.4]

1.12"

1.25"

[28.4]

[31.7]

1 POLE

2 POLE

[13]

[5.7]

2.50"
1.38"

[63.5]

[35.1]

3 POLE

250V 60A
.218/[5.54] DIA.
C'BORE .400/[10.16] DIA. X .63[16] DP

4.83"
[122.7]

1.24"

1.24"

[31.5]

[31.5]

1.79"

1.79"

1.79"

[45.6]

[45.6]

[45.6]

1.48"

.50"

.49"

[12.7]

[12]

.50"

[33.7]

[37.6]

1 POLE

250V 100A

.49
[12]

.50"
[12.7]

1.33"

1.33"

1.33"

[33.7]

[33.7]

.74"
[19]

2.86"

4.23"

2.01"

[72.7]

[108]

[51.1]

2 POLE

.28 (7.1) THRU
.53 (13.5) C'BORE x .60 (15.2) DP

[12.7]

Blocks and Holders

[12]

4.83"
[122.7]

[31.5]

1.24"

.49"

4.83"
[122.7]

3 POLE

3 POLE

2 POLE

.187 HEX
SOCKET

1 POLE

STRIP
GAUGE

.63

2.37

6.13

STRIP
GAUGE

STRIP
GAUGE

STRIP
GAUGE

1.88

2.44
[62.0]

.61

TYP.
1.56

TYP. FUSE q
1.56

3.49
[88.6]

1.93
[49.0]

5.05
[128.3]

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

113

Blocks and Holders

Class H/K5 and R Fuse Blocks
250 Volt
250V 200A

3.00"

9.00"

[76.2]

.50"

2.00"

[13]

[50.8]

[229]
.312" HEX.

.50"

2.00"

4.00"

[13]

[50.8]

[102]

7.13"

7.13"

[181.1]

[181.1]

3.00"

3.00"

[76.2]

[76.2]

2.06"

2.06"

3.01"
[76.5]

[52.3]

[52.3]

1.23"

3.00"

[31.2]

[76.2]

1 POLE

250V 400A

3 POLE

3.50"

9.25"

[88.9]

[235]

11.50"

[16.8]

[26.9]

3.31"
[84]

11.50"

[292.1]

[292.1]

4.00"

4.00"

[101.6]

[101.6]

3.75

3.75"

Blocks and Holders

.66"
1.06"

[95.2]

[95.3]

10.50"
[266.7]

1 POLE

250V 600A

4.50"
[114.3]

3 POLE

.75"
[19]

11.00"
[279.4]

4.37"
[111]

14.00"

14.00"

[355.6]

[355.6]

5.00"

5.00"

[127]

[127]

4.50"

4.50"

[114.3]

[114.3]

12.50"
[317.5]

1 POLE

114

3 POLE

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class H/K5 and R Fuse Blocks
600 Volt
600V 30A
.265" [6.7] DIA. THRU
.05" [12.7] C'BORE
x .44 [11.2] DP.

.34"
[8.7]

3.13"

3.13"

3.13"

[79.4]

[79.4]

[79.4]

.31"
[7.9]

6.25"

6.25"

[159]

[159]

6.25"
[159]

.38"

.25"

[97]

.62"

[6.5]

1.56"

1.63"

3.13"

[39.6]

[41.4]

1.69"

[79.2]

2.94"

4.25"

[74.7]

1 POLE

.69"

[16]

[18]

[42.9]

[108]

2 POLE

3 POLE

600V 60A
1.95"

3.51"

5.08"

[49.5]

[89.2]

[1.29]

6.75"
[171.4]

.281" D.
[7.1]

3.12"
[79.2]

.50" D.
[12.7]

1.81"
[46]

.66"

1.56"

[19.6]

3.12"

[39.6]

[79.2]

1.56"

1.29"

3.12"

[39.6]

[32.8]

[79.2]

1 POLE

2 POLE

.27"
.77"

Blocks and Holders

.62"

[15.7]

[6.8]

[19.6]

2.12"
[53.8]

3 POLE

600V 100A
1 POLE

2 POLE

3 POLE

.28 (7.1) DIA. THRU
.59 (14.9) C'BORE x .64 (16.2) DP.
TYP.

.187 HEX
SOCKET

STRIP
GAUGE

8.13

STRIP
GAUGE

STRIP
GAUGE

4.26
.87
STRIP
GAUGE

1.93

2.60
[66.0]

© 2005 Littelfuse • POWR-GARD™ Products Catalog

.61

1.81
TYP.
5.73
[145.5]

www.littelfuse.com

3.91
[99.3]

2.10
[53.3]

115

Blocks and Holders

Class H/K5 and R Fuse Blocks
600 Volt
600V 200A
3.00"

9.00"

[76.2]

.50"

2.00"

[13]

[50.8]

[229]

.312" HEX.

9.62"

.50"

2.00"

[13]

[50.8]

[102]

3.01"
[76.5]

9.62"

[244]

[244]

3.00"

3.00"

[76.2]

[76.2]

3.31"

3.31"

[84.1]

[84.1]

1.23"

3.00"

[31.2]

[76.2]

1 POLE

600V 400A

3.50 "

9.25"
[235]

14.50"

[16.8]

[26.0]

3.31"
[84.1]

14.50"

[368.3]

[368.3]

7.00"

7.00"

[177.8]

[177.8]

3.75

Blocks and Holders

.66"
1.06"

3 POLE

[88.9]

3.75"

[95.3]

[95.3]

2.25"

10.50"

[57.2]

[266.7]

1 POLE

3 POLE

600V 600A
4.50"
[114.3]

.75"

11.00"

[19]

[279.4]

4.31"
[109.5]

17.00"

17.00"

[431.8]

[431.8]

8.00"

8.00"

[203]

[203]

4.50"

4.50"

[114]

[114]

3.00"
[76.2 ]

1 POLE

116

4.00"

12.50"
[317.5]

3 POLE

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class J Fuse Blocks
600 Volt
Class J 600V
Connector Type
Amp
Rating

No. of
Poles

Catalog
Number

Maximum
Wire Size

(Add Suffix Shown)
Pressure
Box
Screw
Plate
Lug

1
LJ60030-1 S (R)
P (R)
C (R)
2
LJ60030-2 S (R)
P (R)
C (R)
S & P = #10 CU
30
C = #6 CU
3
LJ60030-3 S (R)
P (R)
C (R)
Adder LJ60030-A S (R)
P (R)
C (R)
1
LJ60060-1
C (R)
60
2
LJ60060-2
C (R)
C = #2 CU-AL
3
LJ60060-3
C (R)
1
LJ60100-1
CR
100
#2/0 CU-AL
3
LJ60100-3
CR
1
LJ60200-1
C
200
250 MCM CU-AL
3
LJ60200-3
C
1
LJ60400-1
CR
400
(2) 350 MCM CU-AL
3
LJ60400-3
CR
1
LJ60600-1
CR
600
(2) 500 MCM CU-AL
3
LJ60600-3
CR
Note: Reinforcing springs standard on all Class J fuse blocks rated 100A and above.
*For optional fuse block covers, refer to POWR-Covers section of this catalog. For
reinforcing clips on blocks rated 30-60 amp, add “R” suffix to connector type.

Specifications
Features/Benefits

Voltage Ratings:
Ampere Ratings:
Approvals:

LJ60030

.216[5.5] x .79[20.0] SLOT
MOUNTING HOLE

Recommended Fuses
JTD_ID/JTD (time-delay) and JLS (fast acting) series fuses

1.04"

1.04"

[26.4]

[26.4]

1.69"

1.69"

1.69"

[42.8]

[42.8]

[42.8]

3.38"

3.38"

[85.7]

[85.7]

.30"
TYP.
[7.6]

.57"
1.16"

3.38"
[85.7]

.57" TYP.
[14.5]

[14.5]

[29.4]

1 POLE

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

• Phenolic blocks have side barriers for isolation.
• Spring reinforced fuse clips are standard on 100A and larger blocks.
Reinforcing springs are optional on 30 and 60 amp blocks.
• Space saving 30A design — Up to 45% smaller than existing
30A fuse blocks. 30A interlocking adder block available to create
any number of poles (consult factory for availability). Integral DIN rail
mount allows this block to be securely fastened to 35 mm “hat” type
DIN rails without the use of tools.

600 Volts
0 – 600 amperes
UL Listed: File No. E14721
CSA Certified: File No. LR73091

2.20"

.71"

3.25"
[82.5]

[56.0]

1.95"

[17.9]

[49.5]

2 POLE

3 POLE

www.littelfuse.com

117

Blocks and Holders

Class J Fuse Blocks
600 Volt
LJ60060

.265" x .325" SLOT
[6.7 x 8.3] TYP.

1.67"

3.20"

4.72"

[42.4]

[81.2]

[120]

4.07"

4.07"

4.07"

[103]

[103]

[103]

2.03"

2.03"

2.03"

[51.7]

[51.7]

[51.7]

.57"
.76"

.76"

.76"

[19]

[19]

[19]

.45"
[12]

1.53"
[38.8]

1 POLE

.45"
[12]

1.53"
[38.8]

1.53"
[38.8]
3 POLE

2 POLE

[14 ]

2.09"
.45"

[53.0]

[12]

Blocks and Holders

LJ60100

1 POLE

3 POLE

LJ60200
3.00"
1.31"

[76.2]

[33.39]

.34" THRU [8.6]
.75" C'BORE [19.1]
x .400" DP. [10.2]

6.13"
[156]

.62"

.50"
[13]

2.00"
[50.8]

118

[16]

1 POLE

2.67"

3 POLE

[67.9]

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class J Fuse Blocks
600 Volt
LJ60400

1 POLE

3 POLE

1 POLE

3 POLE

LJ60600

www.littelfuse.com

Blocks and Holders

© 2005 Littelfuse • POWR-GARD™ Products Catalog

119

Blocks and Holders

Class T Fuse Blocks
300 and 600 Volt

Features/Benefits
Bases are molded phenolic. To provide a low resistance connection and
long-range reliability, steel reinforcing springs are supplied as standard.
Larger blocks employ an integral heat sink for maximum heat dissipation.

Specifications
Voltage Ratings:
Ampere Ratings:
Approvals:

300 Volts AC
600 Volts AC
0 – 600 amperes
UL Listed (File No. E14721)
CSA Certified (File No. LR73091)

Recommended Fuses
JLLN (300V) and JLLS (600V) series fuses
300 and 600 volt fuse blocks are designed for use with miniaturized Class T
fuses. Class T fuses are very fast acting, current-limiting, and approximately
one-third the size of electrically comparable Class RK1 fuses.

Class T 300V
Amp
Rating
30
60

Blocks and Holders

100
200
400
600

Class T 600V

No. of
Poles

Catalog
Number

2
3
2
3
4
1
2
3
1
1
1

LT30030-2
LT30030-3
LT30060-2
LT30060-3
LT30060-4
LT30100-1
LT30100-2
LT30100-3
LT30200-1
LT30400-1
LT30600-1

Connector Type
(Add Suffix Shown)
Screw Box Lug

CR
CR
CR
CR
CR
C
C
C
C
C
C

Maximum
Wire Size

Amp
Rating

S = #10 CU
C = #2 CU

30

100
250 MCM CU-AL
(2) 250 MCM CU-AL
(2) 500 MCM CU-AL

2.88

2.88"

[73.0]

[73.0]

2.25

2.25"

[57.2]

[57.2]

200
400
600

2.38
[60.3]

2 POLE

120

Connector Type
(Add Suffix Shown)
Screw Box Lug

SR
SR
SR

.31"
[7.9]

CR
CR
CR
CR
CR
CR
C
C
C
C
C
C

Maximum
Wire Size
S = #10 CU
C = #2 CU-AL

C = #2 CU-AL

#2 ⁄0 CU-AL
250 MCM CU-AL
(2) 250 MCM CU-AL
(2) 500 MCM CU-AL

Note: Reinforcing springs standard on all 600 volt Class T fuse blocks up to 60
amperes. 600 volt Class T blocks 100 amperes and larger have stud mountings.

1.19"

1.13"

[30.2]

[28.6]

0.218" [5.54] THRU
0.39" [9.91] C'BORE
x 0.44" [9.91] DP.

1.13"

1.13
[28.6]

LT60030-1
LT60030-2
LT60030-3
LT60060-1
LT60060-2
LT60060-3
LT60100-1
LT60100-2
LT60100-3
LT60200-1
LT60400-1
LT60600-1

# 2 ⁄0 CU-AL

[30.2]

.31

1
2
3
1
2
3
1
2
3
1
1
1

60

1.19

[7.9]

Catalog
Number

C = #2 CU-AL

Note: Reinforcing springs standard on all 300 volt Class T fuse blocks up to 100
amperes. 300 volt Class T blocks 200 amperes and larger have stud mountings.

LT30030

No. of
Poles

0.62"
[15.9]

[28.6]

3.50"

1.12"

[88.9]

[28.5]

3 POLE

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class T Fuse Blocks
300 Volt
4.47"

LT30060

[113.5]
1.19
[30.2]

1.19"

1.13"

[30.2]

[28.6]

0.218" [5.54] THRU
0.39" [9.91] C'BORE
x 0.44" [9.91] DP.

3.09"
[78.6]

2.88"

2.88
[73.0]

[73.0]

2.25"

2.25
[57.2]

0.31
[7.9]

[57.2]

1.13"

1.13
[28.6]

.31"

0.62"
0.44"

[28.6]

[7.9]

2.38
[60.3]

[15.9]

[11.1]

3.50"

1.28"

0.20"

[88.9]

[32.5]

[5.2]

2.06"
1.20"

52.4]

[30.6]

2 POLE

LT30100
1.37
[34.8]

3 POLE

.203" [5.1]
DIA.HOLE
.37" [9.5]
C'BORE

4 POLE

3.09"
[78.6]

1.41"
[35.7]

5.25"

0.18"
[4.6]

5.25"

4.78"

[133.3]

1.56"

4.12"
[104.6]

[133.3]

[121.4]

4.50"

4.50"

[114.3]

[114.3]

[39.6]

2.39"
[60.7]

[17.5]

1 POLE

LT30200

2.75"

0.69"

[69.8]

[17.5]

LT30400

LT30600
2.37"

1.50"
[38.1]

.281" [7.1]
DIA.HOLE
.50" [12.7]
C'BORE

1.87"
[47.5]

3 POLE

2 POLE

Blocks and Holders

0.69"

2.75"

[60.2]

2.25"

0.62"

[57.1]

[15.7]

0.37"

2.62"

[69.8]

[66.5]

0.62"

[9.5]

.18"

[15.7]

[4.6]

7.00"

8.75"

[177.8]

[222.2]

6.25"
[158.7]

1.69"

7.37"

[42.9]

[187.3]

1.84"

2.03"
[51.6]

[46.7]

8.06"

8.12"

[203.2]

[206.2]

.69"

2.25"

[17.5]

[57.1]

1.12"
[28.6]

1 POLE

© 2005 Littelfuse • POWR-GARD™ Products Catalog

0.28" [7.1] DIA HOLE 0.19"
0.50" [12.7] C'BORE [48]
x 0.43" [10.9] DEEP

1 POLE

www.littelfuse.com

0.28" [7.1] DIA HOLE 0.19"
0.50" [12.7] C'BORE [4.8]
x 0.43" [10.9] DEEP

1 POLE

121

Blocks and Holders

Class T Fuse Blocks
600 Volt
LT60030

0.218" x 0.655"

0.218" x 0.655"
3.13"

1.44"

[5.54 x 16.64]
SLOT 2 PLS.

[5.54 x 16.64]
SLOT 2 PLS.

4.69"

[79.4]

[36.5]

0.91"
[23.0]

[119]

0.78"

1.56"

0.78"

1.56"

[20]

[39.7]

[20]

[39.7]

0.33"
[8.3]

3.38"

3.38"

[85.7]

[85.7]

3.19"
[81.0]

1.69"

1.69"

[42.9]

[42.9]

0.62"
0.55"

[15.9]

[13.9]

1.28"

0.33"
[8.3]

[32.5]

1 POLE

3 POLE

2 POLE

LT60060

0.218" x 0.655"

0.218" x 0.655"
3.13"

1.81"
0.91"

[5.54 x 16.64]
SLOT 2 PLS.

[5.54 x 16.64]
SLOT 2 PLS.

4.69"

[79.4]

[46.0]

0.78"

[23.0]

[20]

[119]

1.56"

0.78"

1.56"

[39.7]

[20]

[39.7]

3.38"

3.38"

[85.7]

[85.7]

2.31"

Blocks and Holders

[58.7]

1.69"

1.69"

[42.9]

[42.9]

0.63"
1.74"
1 POLE

LT60100
1.37
[34.8]

2 POLE

0.203" [5.1]
DIA.HOLE
0.37" [9.5]
C'BORE

3.09'"

4.12"

[78.6]

[104.6]

6.06'

[16]

[44.2]

0.18"
[4.6]

6.06"

4.78"

[153.9]

2.36"

3 POLE

[153.9]

[121.4]

5.31"

5.31"

[134.9]

[134.9]

[6.0]

2.39"
[60.7]

1 POLE

122

0.69"

1.41"

2.75"

[17.5]

[35.7]

[69.8]

2 POLE

0.69"
[17.5]

1.87"
[47.5]

3 POLE

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class T Fuse Blocks
600 Volt
LT60200

1.50"

0.281" [7.1]
DIA.HOLE

[38.1]

0.50" [12.7]
C'BORE

LT60400

.18"

2.37"
[60.2]

2.25"
[57.1]

[4.6]

0.62"
[15.7]

7.75"
[196.8]

8.25"

7.0"

[209.5]

[177.8]

2.50"

2.72"

[63.5]

[69.1]

9.00"
[228.6]

2.25"

0.75"
[19.0]

1.12"

[57.1]

[28.6]

1 POLE

LT60600

0.37"
[9.5]

2.75"

2.62"

[69.8]

[66.5]

0.28" [7.1] DIA HOLE
0.50" [12.7] C'BORE
x 0.43" [10.9] DEEP

1 POLE

0.19"
[4.8]

0.62"
[15.7]

9.0"
[228.6]

2.95"
[75.0]

9.75"
[247.6]

1 POLE

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

0.28" [7.1] DIA HOLE
0.50" [12.7] C'BORE
x 0.43" [10.9] DEEP

0.19"
[4.8]

www.littelfuse.com

123

Blocks and Holders

Class G Fuse Blocks

Specifications
Voltage Ratings:

600 Volts AC (0 – 20A)
480 Volts AC (25 – 60A)
0 – 60 amperes
UL Listed:
15, 20 & 30A (File No. E14721)
60A (File No. E14853)
CSA Certified: 15, 20 & 30A (File No. LR7316)
60A (File No. LR47235)

Ampere Ratings:
Approvals:

Recommended Fuses
SLC series fuses
Amp No. of
Rating Poles

15*

20*

30*

60

Blocks and Holders

Class G fuse blocks are designed for use with 480 volt time-delay,
current-limiting Class G fuses. They meet requirements for branch
circuit protection.
0.36"
[9.13]

LG30015 &
LG30020 MOUNTING
SLOTS

1
2
3
1
2
3
1
2
3
1
2
3

Catalog
Number
LG30015-1
LG30015-2
LG30015-3
LG30020-1
LG30020-2
LG30020-3
L30030G-1
L30030G-2
L30030G-3
LG30060-1
LG30060-2
LG30060-3

Connector Type
(Add Suffix Shown)
Screw

SQ
SQ
SQ
SQ
SQ
SQ
SQ
SQ
SQ

Pressure
Plate

Box
Lug

Maximum
Wire Size

#10 CU

#10 CU
PQ
PQ
PQ

#10 CU
CR
CR
CR

#2 CU-AL

* Note: 15, 20 & 30A Class G fuse blocks are equipped with 20A Quick Connect
Terminals. 60A fuse block equipped with reinforcing spring as standard.

0.77"

0.42"

[19.45]

[10.72]

LG30060

0.17" X 0.22"
[4.37 x 5.56]

1 POLE

0.86"

2 POLE
1.675"
[42.55]

[21.83]

0.42"

1.53"
[38.89]

[10.72]

3.0"
[76.2]

3 POLE
2.375"

0.22"

[60.33]

[5.56]

Note: Refer to the Midget/Class CC Fuse Blocks for L30030G 30A Class G Block dimensions.

124

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class CC/CD and Midget Fuse Blocks
600 Volt
interrupting rating of 200,000 amperes. Midget fuse voltage ratings
vary and their interrupting rating may be as low as 10,000 amperes.

Note that Class CC fuses may be used in Midget fuse blocks, but Midget
fuses cannot be used in Class CC blocks.

Long life
• High-strength materials — Class CC and Midget fuse blocks are
molded of high-strength, high-temperature material to minimize
block breakage during handling and installation, as well as damage
caused by overheating.
• Reduced resistance, less heat — High conductivity, one-piece copper
alloy fuse clips have lower resistance than traditional two-piece brass
or phosphor bronze fuse clips, which minimizes heat rise and watts
loss within the fuse block.

Reduced inventory
• Gangable — Interlocking fuse blocks allow ganging to produce a fuse
block with any number of poles.
• Flexible terminal arrangements — 30A Class CC and Midget fuse
blocks are available with type C box lug, type SQ screw, or type
PQ pressure plate terminals. Type SQ terminals have binding-head
screws, while type PQ terminals have captive pressure plates. Both
terminal types can accommodate side or top mounted quick-connect
terminals. This flexibility allows the accommodation of most needs
and reduces part inventory requirements.
• 60A CD fuse blocks are available with type C box lug terminals.

Safety

• DIN rail mountable — FBDIN1 adapters permit snap-mounting
Littelfuse Class CC and Midget 30 amp fuse blocks directly to
standard or low profile 35mm symmetrical “hat” and 32mm
asymmetrical DIN rails. Patented DIN rail adapters snap securely to
Littelfuse fuse blocks and to DIN rails without tools. They can be
readily removed from rails by lifting the disconnect tab.

• Rejection feature — Class CC fuse blocks have a rejection feature
which prevents the insertion of fuses with lower interrupting rating
or voltage ratings. Class CC fuses are rated 600 volts and have an

• L60060C 60A fuse blocks have patented integral DIN rail adapters
which allow direct mounting to 35mm “hat” type DIN rails.

Specifications

Recommended Fuses

Voltage Rating:
Ampere ratings:

Class CC Blocks:

600 Volts AC/600 Volts DC
L60030C: 30 amps
L60030M: 30 amps
L60060C: 60 amps
Dielectric strength: 1200 volts minimum
Clip/terminals:
Tin-plated copper alloy
Box lug:
Copper
Screw and captive pressure plate: Zinc-plated steel
Base:
Thermoplastic. UL 94VO flammability rating.
Approvals:
Class CC:
UL Listed (File No. E14721)
Midget:
UL Recognized (File No. E14721)
Class CC/Midget:
CSA Certified (File No. LR7316)

CCMR

KLDR

Blocks and Holders

Space saving 600 volt, 30 amp molded case fuse blocks with side
barriers for isolation. Class CC blocks and Midget blocks are identical
except Class CC blocks incorporate a rejection feature to assure proper
fusing.

KLKR

Midget Blocks:
BLF
BLN

BLS
FLA

FLM
FLQ

FLU
KLK

KLKD
KLQ

LA60Q-2

Class CD Blocks:
CCMR
Note: L60030M can be used up to 40A.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

125

Blocks and Holders

Class CC/CD and Midget Fuse Blocks
600 Volt
Class CC 30A Fuse Blocks
Amp
Rating
30

30

30

No. of
Poles
1
2
3
1
2
3
1
2
3

Class CD 60A Fuse Blocks

Catalog
Number
L60030C-1C
L60030C-2C
L60030C-3C
L60030C-1PQ
L60030C-2PQ
L60030C-3PQ
L60030C-1SQ
L60030C-2SQ
L60030C-3SQ

Connector Type
(Add Suffix Shown)

Maximum
Wire Size

Amp
Rating

Box Lug

#6 CU

60

Pressure Plate/
Q. C. Terminal

#10 CU

Screw/ Q. C. Terminal

#10 CU

60

No. of
Poles
1
2
3
Adder
Block

Catalog
Number
L60060C-1C
L60060C-2C
L60060C-3C

Connector Type
(Add Suffix Shown)

Maximum
Wire Size

Box Lug

#6 CU

L60060C-AC

Box Lug

#6 CU

Note: Quick Connect Terminals are rated at 20 amperes.

Midget Fuse Blocks
Amp
Rating
30

30

30

No. of
Poles
1
2
3
1
2
3
1
2
3

Catalog
Number
L60030M-1C
L60030M-2C
L60030M-3C
L60030M-1PQ
L60030M-2PQ
L60030M-3PQ
L60030M-1SQ
L60030M-2SQ
L60030M-3SQ

Connector Type
(Add Suffix Shown)

Maximum
Wire Size

Box Lug

#6 CU

Pressure Plate/
Q. C. Terminal

#10 CU

Screw/ Q. C. Terminal

#10 CU

Note: Quick Connect Terminals are rated at 20 amperes.

0.783"

1.533"

2.283"

[19.89]

1.25"

[38.15]

[57.15]

[31.75]

Blocks and Holders

L60030

3.0"

3.0"

3.0"

[76.2]

[76.2]

[76.2]

1 POLE

2 POLE

3 POLE

1.01"

2.12"

3.12"

1.01"

[25.65]

[53.85]

[79.25]

[25.65]

L60060

3.35"

3.35"

3.35"

3.35"

[85.09]

[85.09]

[85.09]

[85.09]

1.01"

1.89"

[25.65]

1 POLE

126

2 POLE

[48.0]

3 POLE

www.littelfuse.com

ADDER

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Class CC and Midget Fuse Block Accessories
DIN Rail Adapters and Cover Pullers
0.750"

1.490"

0.770"

0.576"

0.484"
0.670"
1.360"

DIN Rail Adapter — FBDIN1
FBDIN1 is for use with 30A Midget, Class CC and Class G fuse blocks.
The patented design permits snap-mounting of Littelfuse Class CC and
Midget 30A fuse blocks directly to standard and low profile 35mm symmetrical “hat” and 32mm asymmetrical DIN rails. Adapters snap securely
to Littelfuse fuse blocks and to DIN rails without tools. They may be
readily removed from rails by lifting the disconnect tab.

DIN 35
Standard Rail

DIN 35
Low Profile

DIN 32
Standard Rail

Blocks and Holders

1.22"

0.665"

3.0"

Cover Puller — SPL001
Littelfuse Class CC and Midget fuse cover puller is designed to provide
protection to personnel, as well as make removal of fuses from fuse
blocks easy and safe. Once installed on the fuse, the cover puller allows
removal of the fuse without the use of a separate puller.
• Meets “Dead Front” requirements for use in control panels.
• Permits safe, easy removal.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

•
•
•
•
•
•

Works with existing fuse block. No special hinged fuse blocks are required.
Easily gangable with 1/ 8" diameter wire.
For use with all 600 volt Class CC and Midget 1/10 — 30A fuses.
Use with Class CC L60030C series and L60030M series fuse blocks.
Label provided for easy fuse identification.
For 2-pole cover puller, order DSPL001.

www.littelfuse.com

127

Blocks and Holders

Fuse Blocks, Holders and Accessories
POWR-SAFE “Dead Front” Holders

Features/benefits
•
•
•
•
•
•
•
•

Meets “Dead Front” requirements and IEC Type IP20 Protection
Mountable on 35mm Din Rail
Blown fuse identification (Indicating versions only)
Easy installation and removal of fuses. No special fuse pullers or tools
required.
UL Listed for branch circuit protection (Class CC versions only)
Compact design
Ventilated design for cooler operation
Indicates above 80 volts (ID versions only)

Ordering information
Indicating
Part Number
LPSC001ID
LPSC002ID
LPSC003ID
LPSC004ID
LPSM001ID
LPSM002ID
LPSM003ID
LPSM004ID

Non-Indicating
Part Number
LPSC001
LPSC002
LPSC003
LPSC004
LPSM001
LPSM002
LPSM003
LPSM004

Littelfuse POWR-SAFE “Dead Front” holders provide optimum
protection to personnel. Indicating and non-indicating versions are
available in 1, 2, 3, or 4 poles for Class CC and Midget fuses.

Multi-pole Assembly Kit:

Dimensions in inches (mm in parentheses)

NOTE: Contact factory for DC rated versions.

•

Fuse Type

Number of Poles

Class CC
Class CC
Class CC
Class CC
Midget
Midget
Midget
Midget

1
2
3
4
1
2
3
4

Order No: CYHP001
(Kit contains 20 connector pincers and 10 handle pins.)

LPSM/LPSC POWR-SAFE Holders

Blocks and Holders

.689
(17.50)

1.38
(35.05)

2.07
(52.58)

2.76
(70.10)

3.032
(77.01)

Specifications
Voltage Rating:
Ampere Rating:
Interrupting Rating:
Terminal type:
Suggested Torque:
Wire Range:

128

600 Volts AC/DC
30 amperes
200 kA (Class CC)
100 kA (Midget)
Pressure plate
15 lb.
#6— #14CU

Material:
Flammability Rating:
Approvals:

www.littelfuse.com

Thermo-Plastic
94VO
UL Listed (LPSC File No: E14721)
UL Recognized (LPSM File No: E14721)
CSA Certified (LPSC/LPSM File No: LR7316)
IEC Type IP20 Protection
CE Certified

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Fuse Blocks, Holders and Accessories
Class J POWR-SAFE Holders

Features/benefits
•
•
•
•

Meets “Dead Front” requirements and IEC Type IP20 protection.
Mountable on 35mm DIN-Rail.
Blown fuse identification (Indicating versions only).
Easy installation and removal of fuses. No special fuse pullers or tools
required.
• UL listed for branch circuit protection.
• Ventilated design for cooler operation.

Ordering Information

Littelfuse POWR-SAFE “Dead Front” fuseholders provide optimum
protection to personnel. An integral DIN-Rail adapter system allows fuse
holders to be mounted on 35mm DIN-Rail without the use of tools or
special parts. Indicating and non-indicating versions are available in 1, 2,
or 3 poles for Class J fuses.

Littelfuse
Catalog No.
LPSJ30-1
LPSJ30-2
LPSJ30-3
LPSJ30-1ID
LPSJ30-2ID
LPSJ30-3ID
LPSJ60-1
LPSJ60-2
LPSJ60-3
LPSJ60-1ID
LPSJ60-2ID
LPSJ60-3ID

Littelfuse
System No.
LPSJ301.Z
LPSJ302.Z
LPSJ303.Z
LPSJ301.ZXID
LPSJ302.ZXID
LPSJ303.ZXID
LPSJ601.Z
LPSJ602.Z
LPSJ603.Z
LPSJ601.ZXID
LPSJ602.ZXID
LPSJ603.ZXID

Multi-Pole Assembly Kit:

No. of
Poles
1
2
3
1
2
3
1
2
3
1
2
3

Pack
Qty.
6
3
2
6
3
2
6
3
2
6
3
2

Voltage
Rating
600V
600V
600V
600V
600V
600V
600V
600V
600V
600V
600V
600V

Ampere
Rating
30A
30A
30A
30A
30A
30A
60A
60A
60A
60A
60A
60A

Options
–
–
–
Indicating
Indicating
Indicating
–
–
–
Indicating
Indicating
Indicating

Order No: US3J2PAK to assemble two LPSJ30-1
US3J3PAK to assemble three LPSJ30-1
US6J2PAK to assemble two LPSJ60-1
US6J3PAK to assemble three LPSJ60-1

Dimensions in inches (mm in parentheses)
Blocks and Holders

30 Amp

60 Amp

Specifications
Voltage Rating:
Interrupting Rating:
Ampere Rating:
Terminal Type:
Suggested Torque:
Wire Range:

600 VAC
200 kA
30 and 60 amperes
Pressure plate
30A – 35 inch-pounds
60A – 45 inch-pounds
#2 – #14CU

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Material:
Flammability Rating:
Approvals:

www.littelfuse.com

Thermo-plastic
94V0
UL Listed
CSA Certified
IEC Type IP20 Protection
CE

129

Blocks and Holders

Fuse Blocks, Holders and Accessories

Features/benefits
• Meets “Dead Front” requirements and IEC Type IP20 Protection for
most applications (see note)
• Easily gangable with optional “gang-slide” adapters
• Added safety to personnel
• Unique design allows Littelfuse Indicator® fuses to be seen through
covers
• Ventilated to avoid fuse derating
• Covers are reusable
• Covers fit most competitor blocks
• LJ60100-3PC is a three pole clear plastic cover
For “Gang Slide” Adapters order:
PCGS-2 for 2 poles
PCGS-3 for 3 poles
NOTE: Contact Factory for specific applications.

Ordering information

POWR-Covers - Fuse Block Covers
Blocks and Holders

Littelfuse fuse block covers protect personnel from accidentally
contacting energized contacts. Covers are available for Class H, R, J,
and CD type fuses up to 100 amps.

Littelfuse Part
Number

For Use With Fuse
Block Number

Voltage

Amp

Fuse
Class

LH25030-PC
LH25060-PC
LH25100-PC
LH60030-PC
LH60060-PC
LH60100-PC
LJ60030-PC
LJ60060-PC
LJ60100-PC*
LJ60100-3PC
L60060C-PC

LH25030/LR25030 series
LH25060/LR25060 series
LH25100/LR25100 series
LH60030/LR60030 series
LH60060/LR60060 series
LH60100/LR60100 series
LJ60030 series only
LJ60060 series only
LJ60100-1CR only
LJ60100-3CR only
L60060C series only

250
250
250
600
600
600
600
600
600
600
600

30
60
100
30
60
100
30
60
100
100
60

H/R
H/R
H/R
H/R
H/R
H/R
J
J
J
J
CD

*Note: For use with Class J fuses with 1” diameter, Littelfuse series JLS.

Specifications
Voltage Rating:
Ampere Rating:

130

600 Volts
Class H:
Class R:
Class J:
Class CD:

0-100 amps
0-100 amps
0-100 amps
0-60 amps

Material:
Approvals:

www.littelfuse.com

Thermoplastic
UL Listed (File No: E184929)
CSA Certified (File No: LR7316)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Fuse Blocks, Holders and Accessories
Fuse Pullers
Littelfuse ergonomically designed fuse pullers are the safe way of
handling power fuses. They offer greater ease in removing fuses. This
new molded design is superior to standard pullers because it offers
a more comfortable and natural grip when pulling fuses, improving
performance. Part No. LPFP

Part Number & Application
Midget Fuse Puller
Pocket Fuse Puller

MFP:
LPFP:

Giant Fuse Puller

GFP:

Tri-Puller

097023:

For 3/16" to 1/2" dia. fuses.
For 0 – 200A 250V,
0 – 100A 600V
( 9/16" – 119/32" dia. fuses)
61 – 600A 250V,
61 – 400A 600V
(11/16" – 219/32" dia. fuses)
For ATO® and glass fuses.

POWR-JAW Clip Clamps
Blocks and Holders

POWR-JAW clamps improve the contact between fuse and clip. The
unnecessary heat from poor contact due to the loss of spring force in
the clips can cause nuisance fuse opening and premature aging of surrounding components.
• High temperature phenolic resin knob designed for the most severe
environments.
• 7 sizes to provide effective coverage.
• Simple design makes installation easy.

Part Number

Volts

Amperes

LCC 1
LCC 2
LCC 2
LCC 4
LCC 5
LCC 6
LCC 7
LCC 8

250
250
600
600
250/600
250/600
250/600
250/600

0-30
35-60
0-30
35-60
70-100
110-200
225-400
450-600

Note: POWR-JAW Clip Clamps are sold individually, not in pairs. A minimum
of 1/ 8” of clearance between the fuse block barrier and fuse clip is required to
install clip clamps.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

131

Blocks and Holders

Fuse Blocks, Holders and Accessories

Ordering Information
Part Number
Bottom
Fuse Length
For Use
Terminal
Range*
With
Standard
Watertight
571 027
571 027P
Straight
5 16
3 8
1⁄ ”–1⁄”
Midget Fuses
571 028
571 028P
Rt. Angle
571 007
571 007P
Straight
113 ⁄ 32” – 11⁄2” Midget Fuses
571 008
571 008P
Rt. Angle
571 OCC
571 OCCP
Straight
11⁄2”
Class CC Fuses
571 RCC
571 RCCP
Rt. Angle
*Fuse diameter is 13/32”.
Note: Contact the factory for versions with pre-assembled wire leads.

571 Series Panel Mounted Fuseholders

O-Rings:
Panel mount fuseholders are available for supplementary or Class CC
branch circuit protection. Class CC fuses have a rejection feature on
one end cap which mates with the rejection feature of Littelfuse Class
CC fuse blocks and fuseholders to prevent the installation of fuses with
lower voltage ratings or interrupting ratings. Watertight version must be
front panel mounted.
0.86"

.172 DIA.
[4.37]

1.312"

[21.84]

[33.33]

0.92"

[28.45]

[33.3]

0.890"
[22.6]

1.34"
[34.04]

Specifications
Voltage Rating:
Ampere Rating:
Dielectric strength:
Terminals:

1.12" 1.310"

[23.37]

901-184 (body)
901-260 (knob)

Molded parts:
Approvals:

1.74"

2.10"

[44.20]

[53.34]

Mounting Hole

600 Volts
30 amperes for Class CC and
Midget fuses
4000 Volts
Tin-plated brass combination solder
and quick-connect
Black thermoplastic
UL Recognized (File No. E14721) — 571 series
UL Recognized for branch circuit protection
— 571 OCC/RCC
CSA Certified (File No. LR7316)

Blocks and Holders

Ordering Information
Part Number
Standard
Watertight
572 027
572 027P
572 028
572 028P
572 007
572 007P
572 008
572 008P
572 OCC
572 OCCP
572 RCC
572 RCCP

NEW

Fuse Length
Range*

For Use With

15 ⁄16” – 13 ⁄ 8”

Midget Fuses

113 ⁄ 32” – 11⁄ 2”

Midget Fuses

11⁄2”

Class CC Fuses

*Fuse diameter is 13/32”
Note: Contact the factory for versions with preassembled wire leads.

572 Series Panel Mounted Fuseholders

Specifications

The 572 series panel mount fuse holders are designed to minimize
installation time. The unique design incorporates a snap-mount feature
that allows the holder to be installed without any tools or mounting
hardware.

Voltage Rating:
Ampere Rating:
Dielectric Strength:
Terminals:
Molder Parts:
Approvals:

2.10”
2.40”

132

Bottom
Terminal
Straight
Rt. Angle
Straight
Rt. Angle
Straight
Rt. Angle

0.69”
1.20”

Mounting:

DIA

www.littelfuse.com

600 Volts
30 Amperes for Class CC and Midget fuses
4000 Volts
Tin-plated brass combination solder and quick-connect
Black thermoplastic
UL Recognized (File No. E14721) – 572 Series
UL Recognized for branch circuit
protection – 571 OCC/RCC
CSA Certified (File No. LR7316)
Designed to fit 14-18 gauge panels with Double
”D” punch or 0.875” knock-out hole.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Fuse Blocks, Holders and Accessories

Ordering Information
Example catalog number: LFFB001
Example system number: LFFB0001Z

Dimensions

LFFB Series Limiter Fuse Block
The Littelfuse LFFB fuse block is designed to accept CNL and CNN
style limiter fuses. Typical applications include: forklifts, golf carts, and
other low voltage battery-operated equipment.

Specifications
Voltage Rating:
Ampere Range:
Approvals:
Construction:

150 VAC/VDC
1 – 400 amperes
Pending
Base — thermoplastic
Studs — steel zinc plated

Recommended fuses
Littelfuse CNL/CNN limiter fuses and competitors’ equivalents.
Blocks and Holders

The Littelfuse LHFB waterproof inline fuse holder is ideal for harsh
environments. The easy to assemble one-piece molded thermoplastic
body is a bright green color for high visibility. The LHFB holder accepts
#12 to #18 gauge wire and features the voltage and ampere rating
molded into the body, along with a wire strip gauge. Withstands
solvents and vibration, for use with 1/ 4” x 11/ 4” fuses.

Installation Instructions
1. Thread wire through fuse holder body.
2. Strip wire insulation per strip gauge.
3. Crimp wire to fuse clip.*
4. Pull wire through and seat fuse clip in the holder body.
5. Insert desired fuse type and rating.
6. Snap holder body together.
*Recommended crimping tools: Thomas & Betts No. WT-111M

NOTE: Wire is not supplied with the holder.

LHFB Inline Fuse Holder

Specifications
Voltage Rating:
Ampere Rating:

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

32 Volts
30 amperes

133

Blocks and Holders

Semiconductor Fuse Blocks

Recommended Fuses
Semiconductor fuses. See tables below.

LSCR001
Semiconductor fuse block selection guide

Modular-designed Semiconductor fuse blocks are designed to
accommodate a wide range of Semiconductor fuses, with a maximum diameter of 3". This modular design greatly reduces inventory
requirements. They are sold in pairs and are constructed of molded
phenolic, with plated steel studs.
1.88"
1.30"
0.70"

LSCR001

0.203" × 0.30" SL

Blocks and Holders

1/4-20" × 1.00"
USABLE LENGTH

2.38"
1.34"

0.25"

2.13"
0.203" × 0.30" SLOT

1.60"
1.00"

LSCR002

1.00"

Ampere Rating

L15S
L25S, LA30QS
L25S
L50S, LA50QS
L50S, LA50QS
L50S
L60S
L60S
L60S
L70S, LA70QS
L70S, LA70QS
KLC
KLC
LA100P

70 – 400
35 – 60
70 – 200
35 – 60
70 – 100
125 – 200
35 – 60
70 – 100
125 – 200
35 – 60
70 – 100
1 – 30
35 – 60
35 – 60

LSCR002
Semiconductor fuse block selection guide

0.70"
0.50"

Fuse Series

Fuse Series

Ampere Rating

L15S, LA15QS
L25S, LA30QS
L25S, LA30QS
L50S, LA50QS
L50S, LA50QS
L50S, LA50QS
L60S
L60S
L60S
L70S, LA70QS
L70S, LA70QS
L70S, LA70QS
KLC
KLC
KLC
KLC
LA100P
JLLN

500 – 800
225 – 700
800
225 – 400
450 – 600
700 – 800
225 – 400
450 – 600
700 – 800
125 – 200
225 – 400
450 – 800
70 – 100
125 – 200
225 – 400
450 – 800
70 – 800
700 – 1200

0.50"

Specifications

0.75"

Voltage rating:

3/8-16"x1.00"
USABLE LENGTH
3.44"
2.44"
0.25"
0.50"

134

LSCR001: Accepts fuses 1” diameter or less at 600V.
Also accepts 13 ⁄16" diameter fuses at 700 — 1000V.
LSCR002: Accepts fuses up to 3" diameter at 1000V.
Ampere ratings:
LSCR001: 1 – 400 ampere capacity.
LSCR002: 70 – 800 ampere capacity.
Approvals:
UL Recognized (File No. E14721)
Stud Size:
LSCR001: 1⁄4 - 20 thread (Torque: 65 In. LBS.)
LSCR002: 3 ⁄8 - 16 thread (Torque: 192 In. LBS.)
Base:
Molded phenolic. 150° C temperature rating.
Terminal construction: Plated steel. Supplied with nut and belleville washer.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

Semiconductor Fuse Blocks

Ordering Information
Littelfuse
Catalog No.
1LS101
1LS102
1LS103
1LS104
1LS108
1LS109
1LS110

Ampere
Rating
100A
400A
400A
600A
400A
400A
400A

Wire Range

Torque Rating

Approvals

#2/0 - 14 CU/AL
250MCM - #6 CU/AL
250MCM - #6 CU/AL
500MCM - #6 CU/AL
250MCM - #6 CU/AL
250MCM - #6 CU/AL
250MCM - #6 CU/AL

120 IN. LBS.
275 IN. LBS.
275 IN. LBS.
375 IN. LBS.
275 IN. LBS.
275 IN. LBS.
275 IN. LBS.

UL Recognized
UL Recognized
UL Recognized
UL Recognized
Self-Certified
Self-Certified
Self-Certified

Specifications
Voltage Rating:
Ampere Range:
Approvals:
Insulator Base:

600 Volts
1 – 600 amperes
UL Recognized under the components program
150° C general purpose phenolic
Box Lug Terminal: Tin plated aluminum

Littelfuse 1LS series modular style semiconductor fuse blocks
accommodate a wide range of semiconductor fuses. Blocks are
provided in pairs with fuse mounting hardware.
•
•
•
•
•

2-piece modular design
General purpose phenolic base
Tin plated aluminum box lugs
Dove-tailed interlocking feature (1LS101 only)
Hex-head bolts and belleville washers provided

Blocks and Holders

Dimensions
Dimensions for reference only.

1LS101

© 2005 Littelfuse • POWR-GARD™ Products Catalog

1LS102

www.littelfuse.com

135

Blocks and Holders

Semiconductor Fuse Blocks

Dimensions
1LS103

1LS104

Blocks and Holders

1LS108

1LS109

1LS110

136

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers

Connectors
Box lug connectors are designed for use with a single, solid or class
B or C stranded conductor. Use of more than one conductor per
connector opening or use of extra-flexible, fine stranded conductors,
such as welding cable, voids the UL Listing, and may cause overheating.
Manufacturers of cable terminations can furnish crimp-on sleeves for
fine stranded conductors which permit these conductors to be used with
box lugs.

Ampere Ratings
The ampere rating per pole for power distribution blocks is based on
the line ampacity of 75°C insulated conductors per NEC Table 310.16. If
60°C insulated conductors are used, load must not exceed the ampacity
of 60°C conductors. Use of conductors rated in excess of 75°C is
permitted (for example 90°C), however, load must not exceed the
ampacity of 75°C conductors.

Ordering Information
POWR-BLOKS power distribution blocks offer a safe, convenient way
of splicing cables, providing a fixed junction tap-off point or splitting
primary power into secondary circuits. LX2xxx-DIN series offers integral
DIN-Rail mount and an optional hinged safety cover.

Distribution Block
Example Part No.

Splicer Block
Example Part No.

Applications

Note: Aluminum blocks can use copper or aluminum wire; copper blocks can
only use copper wire.

Blocks and Holders

Typical applications include heating, air conditioning and refrigeration
systems, elevator systems, material handling equipment, control
panels, motor controls, switchgear, and anywhere power needs to be
distributed to more than one load.

Specifications
Voltage Rating:
Amperage:
Material:

600V
Based on NEC Table 310.16,
using 75°C copper wire
Phenolic rated at 150°C and Thermoplastic rated at
125°C (LD1400 and LS1300 series only)

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Connector:
Flammability Rating:
Approvals:

www.littelfuse.com

Standard: Highly conductive aluminum, tin plated
Copper: Highly conductive copper, tin plated
94V-0
UL Recognized (File No. E171395)
CSA Certified (File No. LR700111)

137

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
Distribution Block Covers
Hinged Plastic Covers
Littelfuse
Part Number
LCH132-1
LCH132-2
LCH132-3

For use with
Distribution/Splicer Block No.
LD2xxx-1DIN / LS2xxx-1DIN
LD2xxx-2DIN / LS2xxx-2DIN
LD2xxx-3DIN / LS2xxx-3DIN

Number
of Poles
1
2
3

Note: Optional hinged covers snap on to blocks.

Littelfuse optional power distribution block covers provide protection
against accidental shorting between poles caused by loose wires,
tools, or other conductive material. They also protect personnel from
accidentally contacting energized connectors. Clear plastic covers are
available for most blocks. New Lx2xxx-xDIN series blocks offer a hinged
cover. To order protective covers, match the number of poles for the
block to the cover.

Blocks and Holders

Clear Plastic Covers
Littelfuse
For use with
Number
Part Number
Distribution/Splicer Block No.
of Poles
LPBC0-2
LD0xxx-2 / LS0xxx-2
2
LPBC0-3
LD0xxx-3 / LS0xxx-3
3
LPBC2-1
LD2xxx-1 / LS2xxx-1
1
LPBC2-2
LD2xxx-2 / LS2xxx-2
2
LPBC2-3
LD2xxx-3 / LS2xxx-3
3
LPBC3-1
LD3xxx-1 / LS3xxx-1
1
LPBC3-2
LD3xxx-2 / LS3xxx-2
2
LPBC3-3
LD3xxx-3 / LS3xxx-3
3
LPBC4-1
LD4xxx-1 / LS4xxx-1
1
LPBC4-2
LD4xxx-2 / LS4xxx-2
2
LPBC4-3
LD4xxx-3 / LS4xxx-3
3
LPBC5-1
LD5xxx-1 / LS5xxx-1
1
LPBC5-2
LD5xxx-2 / LS5xxx-2
2
LPBC5-3
LD5xxx-3 / LS5xxx-3
3
Note: For installation of optional clear plastic covers, use the screws provided with
each cover.

138

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
Distribution Block Selection Guide
Connector
Configuration
Mat’l

Line

Load

AL

Amp
Rating
per Pole

Number
of Poles

115
115
115
115

1
2
3
4

#2 - #14
#2 - #14
#2 - #14
#2 - #14

Openings
per Pole
1
1
1
1

175

2

2⁄0 - #14

175

3

2⁄0 - #14

175

2

175
310

Line

Figure

Littelfuse
Catalog
Number

2
2
2
2

LD1400-1
LD1400-2
LD1400-3
LD1400-4

Load

#10 - #18
#10 - #18
#10 - #18
#10 - #18

Openings
per Pole
4
4
4
4

1

#4 - #14

6

1

LD0401-2

1

#4 - #14

6

1

LD0401-3

2⁄0 - #14

1

#4 - #14

4

1

LD0402-2

3

2⁄0 - #14

1

#4 - #14

4

1

LD0402-3

2

350mcm - #6

1

#4 - #14

6

1

LD0404-2

Wire Range

Wire Range

AL

AL

AL

AL

CU

AL

AL

AL

CU

AL

AL

AL

AL

AL

AL

© 2005 Littelfuse • POWR-GARD™ Products Catalog

3

350mcm - #6

1

#4 - #14

6

1

LD0404-3

1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3
1
2
3

4
4
4
4
4
4
4
4
4
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
8
8
8
12
12
12
6
6
6
8
8
8

3
3
3
3
3
3
5
5
5
5
5
5
5
5
5
5
5
5
5
5
5
6
6
6
6
6
6
7
7
7
7
7
7
7
7
7

LD2570-1
LD2570-2
LD2570-3
LD2970-1
LD2970-2
LD2970-3
LD3552-1
LD3552-2
LD3552-3
LD3553-1
LD3553-2
LD3553-3
LD3555-1
LD3555-2
LD3555-3
LD3953-1
LD3953-2
LD3953-3
LD3955-1
LD3955-2
LD3955-3
LD4551-1
LD4551-2
LD4551-3
LD4560-1
LD4560-2
LD4560-3
LD5552-1
LD5552-2
LD5552-3
LD5579-1
LD5579-2
LD5579-3
LD5586-1
LD5586-2
LD5586-3

1

2⁄0 - #14

4

7

LD5587-1

665

2

2⁄0 - #14

4

7

LD5587-2

665

3

1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
1
1
1
2
2
2
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
1
1
1
1
1
1

#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#4 - #14
#4 - #14
#4 - #14
#2 - #14
#2 - #14
#2 - #14
#4 - #14
#4 - #14
#4 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
#2 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14

665

2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
400mcm - #6
400mcm - #6
400mcm - #6
400mcm - #6
400mcm - #6
400mcm - #6
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
500mcm - #4
500mcm - #4
500mcm - #4
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
500mcm - #4
500mcm - #4
500mcm - #4
400mcm - #6
400mcm - #6
400mcm - #6
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
500mcm - #4
350mcm - #6
500mcm - #4
350mcm - #6
500mcm - #4
350mcm - #6

2⁄0 - #14

4

7

LD5587-3

www.littelfuse.com

Blocks and Holders

CU

310
175
175
175
175
175
175
335
335
335
335
335
335
350
350
350
380
380
380
350
350
350
380
380
380
335
335
335
380
380
380
380
380
380
760
760
760

139

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
Distribution Block Selection Guide
Connector Configuration
Mat’l

AL

AL

CU

CU

AL

AL

Load

Number
of Poles

760

Line

Load
Figure

Littelfuse
Catalog
Number

12

7

LD5592-1

#4 - #14

12

7

LD5592-2

#4 - #14

12

7

LD5592-3

#2 - #14

8

7

LD5594-1

Wire Range

Openings
per Pole

Wire Range

Openings
per Pole

1

500mcm-#4

2

#4 - #14

760

2

500mcm-#4

2

760

3

500mcm-#4

2

380

1

500mcm-#4

1

380

2

500mcm-#4

1

#2 - #14

8

7

LD5594-2

380

3

500mcm-#4

1

#2 - #14

8

7

LD5594-3

760

1

500mcm-#4

2

2⁄0 - #14

8

7

LD5986-1

760

2

500mcm-#4

2

2⁄0 - #14

8

7

LD5986-2

760

3

500mcm-#4

2

2⁄0 - #14

8

7

LD5986-3

760

1

500mcm-#4

2

#2 - #14

12

7

LD5992-1

760

2

500mcm-#4

2

#2 - #14

12

7

LD5992-2

760

3

500mcm-#4

2

#2 - #14

12

7

LD5992-3

175
175
175
175
175
175
175
175
175
175
175
175

1
2
3
Adder
1
2
3
Adder
1
2
3
Adder

2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14

1
1
1
1
1
1
1
1
1
1
1
1

#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14
#4 - #14

4
4
4
4
6
6
6
6
4
4
4
4

4
4
4
4
4
4
4
4
4
4
4
4

LD2570-1DIN
LD2570-2DIN
LD2570-3DIN
LD2570-ADIN
LD2580-1DIN
LD2580-2DIN
LD2580-3DIN
LD2580-ADIN
LD2970-1DIN
LD2970-2DIN
LD2970-3DIN
LD2970-ADIN

Blocks and Holders

CU

Line

Amp
Rating
per Pole

140

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
Splicer Block Selection Guide
Connector
Configuration
Mat’l

Line

Load

Amp
Rating
per Pole

Number
of Poles

310

Line

Load
Figure

Littelfuse
Catalog
Number

1

LS0303-2

Wire Range

Openings
per Pole

Wire Range

Openings
per Pole

2

350mcm-#6

1

350mcm-#6

1

310

3

350mcm-#6

1

350mcm-#6

1

1

LS0303-3

115
115
115
115

1
2
3
4

#2 - #14
#2 - #14
#2 - #14
#2 - #14

1
1
1
1

#2 - #14
#2 - #14
#2 - #14
#2 - #14

1
1
1
1

2
2
2
2

LS1300-1
LS1300-2
LS1300-3
LS1300-4

150

1

1⁄0 - #18

1

1⁄0 - #18

1

3

LS2121-1

150

2

1⁄0 - #18

1

1⁄0 - #18

1

3

LS2121-2

150

3

1⁄0 - #18

1

1⁄0 - #18

1

3

LS2121-3

115

1

#2 - #14

1

#2 - #14

1

3

LS2552-1

115

2

#2 - #14

1

#2 - #14

1

3

LS2552-2

115

3

#2 - #14

1

#2 - #14

1

3

LS2552-3

175

1

2⁄0 - #14

1

2⁄0 - #14

1

3

LS2572-1

175

2

2⁄0 - #14

1

2⁄0 - #14

1

3

LS2572-2

175

3

2⁄0 - #14

1

2⁄0 - #14

1

3

LS2572-3

255

1

250mcm-#6

1

250mcm-#6

1

5

LS3123-1

255

2

250mcm-#6

1

250mcm-#6

1

5

LS3123-2

255

3

250mcm-#6

1

250mcm-#6

1

5

LS3123-3

255

1

250mcm-#6

1

250mcm-#6

1

5

LS3124-1

255

2

250mcm-#6

1

250mcm-#6

1

5

LS3124-2

255

3

250mcm-#6

1

250mcm-#6

1

5

LS3124-3

310

1

350mcm-#6

1

350mcm-#6

1

5

LS3126-1

310

2

350mcm-#6

1

350mcm-#6

1

5

LS3126-2
LS3126-3

AL

AL

CU

AL

AL

AL

CU

AL

AL

AL

AL

CU

© 2005 Littelfuse • POWR-GARD™ Products Catalog

310

3

350mcm-#6

1

350mcm-#6

1

5

420

1

600mcm-#4

1

600mcm-#4

1

6

LS4557-1

420

2

600mcm-#4

1

600mcm-#4

1

6

LS4557-2

420

3

600mcm-#4

1

600mcm-#4

1

6

LS4557-3

620

1

350mcm-#4

2

350mcm-#4

2

7

LS5129-1

620

2

350mcm-#4

2

350mcm-#4

2

7

LS5129-2

620

3

350mcm-#4

2

350mcm-#4

2

7

LS5129-3

760

1

500mcm-#4

2

500mcm-#4

2

7

LS5301-1

760

2

500mcm-#4

2

500mcm-#4

2

7

LS5301-2

760

3

500mcm-#4

2

500mcm-#4

2

7

LS5301-3

175
175
175
175
175
175
175
175

1
2
3
A
1
2
3
A

2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14

1
1
1
1
1
1
1
1

2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14
2⁄0 - #14

1
1
1
1
1
1
1
1

4
4
4
4
4
4
4
4

LS2572-1DIN
LS2572-2DIN
LS2572-3DIN
LS2572-ADIN
LS2972-1DIN
LS2972-2DIN
LS2972-3DIN
LS2972-ADIN

www.littelfuse.com

Blocks and Holders

AL

141

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
LX0XXX

.218 x .375"

.07"

.218 x .375"

.07"

[5.5 x 9.5]SLOT

[1.8]

[5.5 x 9.5]SLOT

[1.8]

2.90"

2.90"

[73.7]

[73.7]

1.00"

1.00"

[25.4]

[25.4]

3.38"

4.63"

[85.8]

[118]

3.52"

.65 x .375"

[89.3]

3.38"

4.73"

.265 x .375"

[121]

[6.7 x 9.5] SLOT

[85.8]

[6.7 x 9.5] SLOT

4.13"

5.38"

[104.8]

[137]

2 POLE

3 POLE

Figure 1
LX1XXX

Blocks and Holders

1.52
[38.7]

3 POLE

2 POLE

1 POLE

4 POLE

Figure 2
LX2XXX
.31"

.56"

.56"
.205 [5.2]
DIA. HOLE

[14]

[14]

2.25"

2.25"

[57.2]

[57.2]

2.88"

2.88"

[73.0]

[73.0]

[42]

.56"

1.78"

.63"

[14]

[45.2]

[16.1]

2.25"
[57.2]

2.88"
[73.0]

.62"

.62"

[16]

[16]

1 POLE

[69.9]

1.62"

[49.2]

[28.6]
[7.9]

2.75"

1.94"

1.13"

2 POLE

3 POLE

Figure 3

142

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
LX2XXX-XDIN
2.42
[61.5]

2 POLE

1 POLE

Blocks and Holders

3 POLE

ADDER

Figure 4

LX3XXX

1.94"

3.47"

[49.3]

[88.1]

5.00"

.97"

.97"

1.53"

.97"

1.53"

[25]

(25)

[38.9]

[25]

[38.9]

3.38"
(85.7)

4.00"

4.00"

[102]

[102]

.31"
[7.9]

1.17"
[29.7]

2.61"

[127.0]

3.38"

3.38"

(85.7)

[85.7]

[66.2]

4.00"
[101.6]

.31"
[7.9]

1 POLE

1.17"

1.17"

.31"

[29.7]

[29.7]

[7.9]

2 POLE

3 POLE

Figure 5

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

143

Blocks and Holders

POWR-BLOKS™
Distribution/Splicer Blocks and Covers
LX4XXX

[7.9]

6.04"

4.16"

2.28"
.31"

1.14"
[29.0]

[7.9]

.31"
1.14"
[29.0]

4.13"
[105]

1.88"

[7.9]

[47.8]

4.13"

4.13"

[105]

[105]

4.75"

4.75"

4.75"

[121]

[121]

[121]

1 POLE

2.92
(74.0)

[153]

[106]

[57.9]

.31"

1.14"

1.88"

1.88"

[29.0]

[47.8]

[47.8]

2 POLE

3 POLE

Figure 6

Blocks and Holders

LX5XXX
3.17"

5.88"

[80.4]

[149]

8.54"
[217]

1.58"

1.58"

2.69"

1.58"

2.69"

2.30"

3.12"

[40.2]

[40.2]

[68.2]

[40.2]

[68.2]

[58.5]

[79.2]

4.75"

4.75"

[121]

4.75"

[121]

[121]

5.50"

5.50"

[140]

[140]

5.50"
[140]

.37"

.37"

.37"

(9.5)

[9.5]

[9.5]

1 POLE

2 POLE

3 POLE

Figure 7

144

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

In-Line Watertight Fuseholders

Littelfuse 600 volt in-line watertight fuse holders are the ideal answer
for all high humidity and corrosive environments where fuses are
required. Available in both breakaway and non-breakaway, single and
double pole versions, these fuseholders allow maximum flexibility for
any application.

Applications
Street, alley, and parking lot lighting
Security and perimeter lighting
Traffic signals
Outdoor illuminated signs
Sports lighting
Boat electrical circuits
Tractors and yard equipment
General outdoor circuit protection

Benefits

TO
LOAD

• Safety — Permits individual fixture or device to be disconnected from
circuit for servicing. Eliminates possibility of shock.
• Individual fixture fusing — Prevents loss of one fixture through
accident, vandalism, or end of life from darkening the entire circuit.
• Simplifies maintenance — Being able to immediately identify the one
faulted fixture eliminates testing the entire circuit, speeds repair, and
allows the individual unit to be serviced while the rest of the circuit is
functioning.
• Reduces damage from fault — Can prevent faulted ballast or other
failure from severely damaging fixture or device, reducing necessary
repair or need of replacement.

Blocks and Holders

ELECTRICAL TAPE

Features
• Watertight — Internal O-ring provides watertight seal.
• Superior terminal seals — Ultrasonically-welded terminals provide
maximum strength and eliminate leaking at terminals.
• Break resistant — Fiberglass reinforced polymer body resists damage
from dropping or impact much better than phenolic look-alikes.
• Flexible terminations — Accommodates a wide range of stranded or
solid copper or aluminum conductors. Terminations are available for
one or two conductors, with either crimp or screw terminals.
• One-pole and two-pole models available to accommodate all system
voltages up to 600V.

TO
SOURCE

Specifications
Voltage rating:
Ampere rating:
Approvals:
LEB/ LEX series:

LEC/ LEY series:

600 Volts
30 amperes
200,000 amperes rms symmetrical (with Class CC fuses)

Mating fuses
LEB/LEX series:

UL Recognized Miscellaneous
Fuseholder per UL 512 (File No. E14721)
CSA Certified per C22.2, No. 39 (File No. LR7316)
UL Listed Class CC Branch Circuit
Fuseholder per UL 512 (File No. E14721)
CSA Certified per C22.2, No. 39 (File No. LR7316)

LEC/LEY series:

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Accepts all 1 1⁄2” x 13 ⁄ 32” Midget and Class CC fuses
Littelfuse types BLF, BLN, FLM, FLQ, KLK, KLKD, KLKR,
KLDR and CCMR.
Accepts only Class CC fuses.
Littelfuse types KLKR, KLDR and CCMR.

145

Blocks and Holders

In-Line Watertight Fuseholders

One-pole LEB and LEC Fuseholders
LEB/LEC

Basic single-pole LEB and LEC watertight fuseholders provide
protection for a variety of circuits. LEB fuseholders ac cept all
13 32
/ ” x 11/ 2” midget fuses providing supplemental overcurrent
protection. LEC fuseholders are UL Listed Class CC fuseholders
which accept only Class CC fuses and meet National Electrical Code
requirements for branch circuit protection. The most common use for
either fuseholder is for protection of lighting circuits. However, consider
them wherever there is a need for secure in-line protection, from boat
circuits to electric wheelchairs. Great flexibility is achieved when the
basic holders are combined with breakaway receptacles, Y-terminals
and insulating boots.

LEX/LEY

Two-pole LEX and LEY Fuseholders

LET

LEX and LEY fuseholders are intended for use on line-to-line circuits up
to 600 volts and are ideal for line-to-line loads such as 240 or 480 volt
ballasts. When the line and load sections of LEX and LEY fuseholders
are separated, or when the fuseholder is removed from a two-pole
breakaway receptacle, both lines are disconnected simultaneously. This
prevents the possibility of shock from backfeeding through an exposed
fuse, which could happen with single-pole fuseholders. The LEX holder
is a two-pole version of the LEB and accepts midget fuses, providing
supplementary overcurrent protection. The LEY holder is a two-pole
version of the LEC, which accepts only Class CC fuses, and may be
used to provide branch circuit protection. Both fuseholders may be
equipped with Y-terminals, breakaway receptacles and insulating boots.

One-pole LET Solid Neutral Disconnects
Blocks and Holders

The LET solid neutral disconnect is designed for use as a no-load
non-fused disconnect. Similar in design to the LEB series fuseholders,
the LET is easily identified by its all white body. Internally, it has
a permanently installed solid tin-plated copper neutral slug which
eliminates the possibility of placing a fuse in the neutral side of the
circuit. Fusing the neutral side causes a safety hazard and also violates
the National Electrical Code. The LET is available in both breakaway and
non-breakaway configurations with a wide variety of terminations.

Breakaway Feature

Breakaway

146

Littelfuse LEB, LEC, and LET single-pole fuseholders and LEX and LEY
two-pole fuseholders are available with an optional breakaway feature
required to meet state and federal highway commission standards
requiring fuseholders to readily disconnect from the line in case of
a pole knockdown. The breakaway feature consists of a receptacle
permanently attached to the power line and a fuseholder with matching
terminals. When knockdown occurs, the parts separate readily. The
breakaway receptacle terminal is deeply recessed so that energized
parts are not exposed. The fuse remains safely enclosed inside the now
de-energized watertight fuseholder. After the pole has been reinstalled,
the fuseholder is easily plugged into the receptacle, immediately
restoring service. The breakaway feature may also be used in marinas,
travel trailer parks and other locations where circuits subjected to strain
must be safely disconnected.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

In-Line Watertight Fuseholders

WPB1 BOOT
(OPTIONAL)

A & B Crimp
Terminal

WPB1 BOOT
(OPTIONAL)

4.5"
9.3"
( ASSEMBLED LENGTH )

C & D Crimp
Terminal

INSULATING BOOT
(STANDARD)

J Terminal

INSULATING BOOT
(STANDARD)

4.5"
5.4"
( ASSEMBLED LENGTH )
10.3"
( ASSEMBLED LENGTH )

Y Terminal

Insulating Boots
Molded from engineering grade thermoplastics, the
WPB1 and WPB2 provide a high resistance to corrosive environments and deliver a watertight seal.
Boots are supplied as standard with all breakaway
versions. Weatherproof boots WPB1 and WPB2
can be purchased separately for all non-breakaway
holders. Part number WPB1 contains one standard
boot for use with A, B, C, D, or J termination. Part
number WPB2 contains one Y-pole boot for use with
the Y-pole termination. For watertight protection
of non-breakaway Y-pole fuseholders, order one
WPB1 and one WPB2 boot. For non-breakaway
double-pole LEX and LEY holders with A, B, C, D,
or J terminations, order four WPB1 boots. These
insulating boots are designed to fit snugly onto wire
insulation, but for best results with varying wire
insulation sizes, a tape wrap should be completed.

4.5"
9.3"
( ASSEMBLED LENGTH )

Blocks and Holders

4.2"
5.3"
( ASSEMBLED LENGTH )
10.3"
( ASSEMBLED LENGTH )

Recommended Crimping Tools

Terminal Size

T&B Part No.

Burndy Part No.

A
B
C
D

WT161M
WT161M
WT115A
WT115A

–
MR4C
Hypress Y34A
Hypress Y34A

The following crimping tools or equivalents may be used on either the
non-breakaway or breakaway watertight in-line fuseholders.

Ordering Information
To order Littelfuse in-line fuseholders and disconnects by part number,
refer to the charts on the next page.

LEB - AA - S
Type
Load Side/Term Size

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Breakaway Feature
Line Side/Term Size

Fuseholder Type

Description

LEB
LEC
LET
LEX
LEY

One-pole in-line fuseholder for Midget and Class CC fuses
One-pole in-line fuseholder for Class CC fuses
One-pole in-line solid neutral disconnect
Two-pole in-line fuseholder for Midget and Class CC fuses
Two-pole in-line fuseholder for Class CC fuses

www.littelfuse.com

147

Blocks and Holders

In-Line Watertight Fuseholders
Selection Guide For Single Pole LEB/LEC Fuseholders
Load Terminal Selection
Standard Breakaway
Fuse Type
Part No.
Part No.
LEB-AA
LEC-AA

LEB-AA-S
LEC-AA-S

Midget
Class CC

Copper
Crimp

LEB-AB
LEC-AB

LEB-AB-S
LEC-AB-S

Midget
Class CC

Copper
Crimp

LEB-AC
LEC-AC
LEB-AD
LEC-AD
LEB-AJ
LEC-AJ

—
—
—
—
LEB-AJ-S
LEC-AJ-S

Midget
Class CC
Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp
Copper
Crimp

LEB-AYC
LEC-AYC

LEB-AYC-S
LEC-AYC-S

Midget
Class CC

Copper
Crimp

LEB-BA
LEC-BA

LEB-BA-S
LEC-BA-S

Midget
Class CC

Copper
Crimp

LEB-BB
LEC-BB

LEB-BB-S
LEC-BB-S

Midget
Class CC

Copper
Crimp

LEB-BC
LEC-BC

—
—

Midget
Class CC

Copper
Crimp

LEB-BD
LEC-BD

Blocks and Holders

LEB-BJ
LEC-BJ

148

Terminal
Type

—
—
LEB-BJ-S
LEC-BJ-S

Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp

LEB-BYC
LEC-BYC

LEB-BYC-S
LEC-BYC-S

Midget
Class CC

Copper
Crimp

LEB-CA
LEC-CA

—
—

Midget
Class CC

Copper
Crimp

LEB-CB
LEC-CB

—
—

Midget
Class CC

Copper
Crimp

LEB-CC
LEC-CC
LEB-CD
LEC-CD
LEB-CJ
LEC-CJ

—
—
—
—
—
—

Midget
Class CC
Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp
Copper
Crimp

LEB-CYC
LEC-CYC

—
—

Midget
Class CC

Copper
Crimp

LEB-DA
LEC-DA

—
—

Midget
Class CC

Copper
Crimp

LEB-DB
LEC-DB

—
—

Midget
Class CC

Copper
Crimp

LEB-DC
LEC-DC
LEB-DD
LEC-DD
LEB-DJ
LEC-DJ

—
—
—
—
—
—

Midget
Class CC
Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp
Copper
Crimp

LEB-DYC
LEC-DYC

—
—

Midget
Class CC

Copper
Crimp

LEB-JJ
LEC-JJ

LEB-JJ-S
LEC-JJ-S

Midget
Class CC

Copper
Set Screw

LEB-JYC
LEC-JYC

LEB-JYC-S
LEC-JYC-S

Midget
Class CC

Copper
Set Screw

Load
No. of
Terminal
Wires per
Wire Size
Terminal
Range
#12 to #8
1
#12
2
#12 to #8
1

Line Terminal Selection

Solid
Wire

Stranded
Wire

Terminal
Type

X
X
X

X
X
X

Copper
Crimp

#12

2

X

X

#12 to #8
#12
#12 to #8
#12
#12 to #8
#12
#12 to #8

1
2
1
2
1
2
1

X
X
X
X
X
X
X

X
X
X
X
X
X
X

#12

2

X

X

#10
#6
#4
#10
#6
#4
#10
#6
#4
#10
#6
#4
#10
#6
#4
#10
#6
#4
#8
#4
#8

2
1
1
2
1
1
2
1
1
2
1
1
2
1
1
2
1
1
2
1
2

X
X
—
X
X
—
X
X
—
X
X
—
X
X
—
X
X
—
X
—
X

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

#4

1

—

X

#8
#4
#8
#4
#8
#4
#8

2
1
2
1
2
1
2

X
—
X
—
X
—
X

X
X
X
X
X
X
X

#4

1

—

X

#6
#2
#6

2
1
2

X
—
X

X
X
X

#2

1

—

X

#6
#2
#6
#2
#6
#2
#6

2
1
2
1
2
1
2

X
—
X
—
X
—
X

X
X
X
X
X
X
X

#2

1

—

X

#12 to #8
#10 to #2
#12 to #8

1
1
1

X

—

—

X

X

—

#10 to #2

1

—

X

www.littelfuse.com

Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Set-Screw
“Y” Type
Copper
Set-Screw
Copper
Crimp
Copper
Crimp
Copper
Crimp

Line
No. of
Terminal
Wires per
Wire Size
Terminal
Range
#12 to #8
1
#12
2
#10
2
#6
1
#4
1
#8
2
#4
1
#6
2
#2
1
#12 to #8
1
#10 to #2
1
#12 to #8
1
#10 to #2

1

Solid
Wire

Stranded
Wire

X
X
X
X
—
X
—
X
—
X
—
X

X
X
X
X
X
X
X
X
X
—
X
—

—

X

#12 to #8

1

X

X

#12

2

X

X

#10
#6
#4
#8

2
1
1
2

X
X
—
X

X
X
X
X

#4

1

—

X

Copper
Crimp

#6

2

X

X

#2

1

—

X

Copper
Set-Screw

#12 to #8

1

X

—

#10 to #2

1

—

X

“Y” Type
Copper
Set-Screw
Copper
Crimp

#12 to #8

1

X

—

Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Set-Screw
“Y” Type
Copper
Set-Screw
Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Set-Screw
“Y” Type
Copper
Set-Screw
Copper
Set-Screw
“Y” Type
Copper
Set-Screw

#10 to #2

1

—

X

#12 to #8
#12
#10
#6
#4
#8
#4
#6
#2
#12 to #8
#10 to #2
#12 to #8

1
2
2
1
1
2
1
2
1
1
1
1

X
X
X
X
—
X
—
X
—
X
—
X

X
X
X
X
X
X
X
X
X
X
X
—

#10 to #2

1

—

X

#12 to #8
#12
#10
#6
#4
#8
#4
#6
#2
#12 to #8
#10 to #2
#12 to #8

1
2
2
1
1
2
1
2
1
2
1
1

X
X
X
X
—
X
—
X
—
X
—
X

—
X
X
X
X
X
X
X
X
X
X
—

#10 to #2

1

—

X

#12 to #8
#10 to #2
#12 to #8

1
1
1

X
—
X

—
X
—

#10 to #2

1

—

X

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Blocks and Holders

In-Line Watertight Fuseholders
Selection Guide For Double Pole LEX/LEY Fuseholders
Load Terminal Selection
Standard Breakaway
Fuse Type
Part No.
Part No.

Terminal
Type

LEX-AA
LEY-AA

LEX-AA-S
LEY-AA-S

Midget
Class CC

Copper
Crimp

LEX-AB
LEY-AB

LEX-AB-S
LEY-AB-S

Midget
Class CC

Copper
Crimp

LEX-AC
LEY-AC
LEX-AD
LEY-AD

—
—
—
—

Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp

LEX-AYC
LEY-AYC

LEX-AYC-S
LEY-AYC-S

Midget
Class CC

Copper
Crimp

LEX-BA
LEY-BA

LEX-BA-S
LEY-BA-S

Midget
Class CC

Copper
Crimp

LEX-BB
LEY-BB

LEX-BB-S
LEY-BB-S

Midget
Class CC

Copper
Crimp

LEX-BC
LEY-BC

—
—

Midget
Class CC

Copper
Crimp

—
—

Midget
Class CC

Copper
Crimp

LEX-BYC
LEY-BYC

LEX-BYC-S
LEY-BYC-S

Midget
Class CC

Copper
Crimp

LEX-CA
LEY-CA

—
—

Midget
Class CC

Copper
Crimp

LEX-CB
LEY-CB

—
—

Midget
Class CC

Copper
Crimp

LEX-CC
LEY-CC
LEX-CD
LEY-CD
LEX-CJ
LEY-CJ

—
—
—
—
—
—

Midget
Class CC
Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp
Copper
Crimp

LEX-CYC
LEY-CYC

—
—

Midget
Class CC

Copper
Crimp

LEX-DA
LEY-DA

—
—

Midget
Class CC

Copper
Crimp

LEX-DB
LEY-DB

—
—

Midget
Class CC

Copper
Crimp

LEX-DC
LEY-DC
LEX-DD
LEY-DD
LEX-DJ
LEY-DJ

—
—
—
—
—
—

Midget
Class CC
Midget
Class CC
Midget
Class CC

Copper
Crimp
Copper
Crimp
Copper
Crimp

LEX-DYC
LEYDYC

—
—

Midget
Class CC

Copper
Crimp

LEX-JJ
LEY-JJ

LEX-JJ-S
LEY-JJ-S

Midget
Class CC

Copper
Set-Screw

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Line Terminal Selection

Solid
Wire

Stranded
Wire

Terminal
Type

X
X
X

X
X
X

Copper
Crimp

#12

2

X

X

#12 to #8
#12
#12 to #8
#12
#12 to #8

1
2
1
2
1

X
X
X
X
X

X
X
X
X
X

#12

2

X

X

#10
#6
#4
#10
#6
#4
#10
#6
#4
#10
#6
#4
#10
#6
#4
#8
#4
#8

2
1
1
2
1
1
2
1
1
2
1
1
2
1
1
2
1
2

X
X
—
X
X
—
X
X
—
X
X
—
X
X
—
X
—
X

X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X

#4

1

—

X

#8
#4
#8
#4
#8
#4
#8

2
1
2
1
2
1
2

X
—
X
—
X
—
X

X
X
X
X
X
X
X

#4

1

—

X

#6
#2
#6

2
1
2

X
—
X

X
X
X

#2

1

—

X

#6
#2
#6
#2
#6
#2
#6

2
1
2
1
2
1
2

X
—
X
—
X
—
X

X
X
X
X
X
X
X

#2

1

—

X

#12 to #8
#10 to #2

1
1

X
—

—
X

www.littelfuse.com

Copper
Crimp
Copper
Crimp
Copper
Crimp
“Y” Type
Copper
Set-Screw

Line
No. of
Terminal
Wires per
Wire Size
Terminal
Range
#12 to #8
1
#12
2
#10
2
#6
1
#4
1
#8
2
#4
1
#6
2
#2
1
#12 to #8
1

Solid
Wire

Stranded
Wire

X
X
X
X
—
X
—
X
—
X

X
X
X
X
X
X
X
X
X
—

#10 to #2

1

—

X

Copper
Crimp

#12 to #8

1

X

X

#12

2

X

X

Copper
Crimp

#10
#6
#4
#8

2
1
1
2

X
X
—
X

X
X
X
X

Copper
Crimp

#4

1

—

X

Copper
Crimp

#6

2

X

X

#2

1

—

X

“Y” Type
Copper
Set-Screw
Copper
Crimp

#12 to #8

1

X

—

#10 to #2

1

—

X

#12 to #8
#12
#10
#6
#4
#8
#4
#6
#2
#12 to #8
#10 to #2
#12 to #8

1
2
2
1
1
2
1
2
1
1
1
1

X
X
X
X
—
X
—
X
—
X
—
X

X
X
X
X
X
X
X
X
X
—
X
—

Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Set-Screw
“Y” Type
Copper
Set-Screw
Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Crimp
Copper
Set-Screw
“Y” Type
Copper
Set-Screw
Copper
Set-Screw

#10 to #2

1

—

X

#12 to #8
12
#10
#6
#4
#8
#4
#6
#2
#12 to #8
#10 to #2
#12 to #8

1
2
2
1
1
2
1
2
1
1
1
1

X
X
X
X
—
X
—
X
—
X
—
X

X
X
X
X
X
X
X
X
X
—
X
—

#10 to #2

1

—

X

#12 to #8

1
1

X
—

—
X

Blocks and Holders

LEX-BD
LEY-BD

Load
No. of
Terminal
Wires per
Wire Size
Terminal
Range
#12 to #8
1
#12
2
#12 to #8
1

149

Blocks and Holders

In-Line Watertight Fuseholders

Selection Guide For Solid Neutral LET Fuseholders
Load Terminal Selection
Standard Breakaway
Fuse Type
Part No.
Part No.

Terminal
Type

LET-AA

LET-AA-S

Solid
Neutral

Copper
Crimp

LET-AB

LET-AB-S

Solid
Neutral

Copper
Crimp

LET-AYC

LET-AYC-S

Solid
Neutral

Copper
Crimp

LET-BA

LET-BA-S

Solid
Neutral

Copper
Crimp

LET-BB

LET-BB-S

Solid
Neutral

LET-BYC

LET-BYC-S

Solid
Neutral

Copper
Crimp

LET-JJ

LET-JJ-S

Solid
Neutral

Copper
Set-Screw

LET-JYC

LET-JYC-S

Solid
Neutral

Copper
Set-Screw

Copper
Crimp

Load
No. of
Terminal
Wires per
Wire Size
Terminal
Range
#12 to #8
1
#12
2
#12 to #8
1

Line Terminal Selection

Solid
Wire

Stranded
Wire

Terminal
Type

X
X
X

X
X
X

Copper
Crimp

#12

2

X

X

#12 to #8

1

X

X

#12

2

X

X

#10
#6
#4
#10
#6
#4
#10
#6
#4
#12 to #8
#10 to #2
#12 to #8

2
1
1
2
1
1
2
1
1
1
1
1

X
X
—
X
X
—
X
X
—
X
—
X

X
X
X
X
X
X
X
X
X
—
X
—

#10 to #2

1

—

X

Copper
Crimp
“Y” Type
Copper
Set-Screw
Copper
Crimp
Copper
Crimp
“Y” Type
Copper
Set-Screw
Copper
Set-Screw
“Y” Type
Copper
Set-Screw

Line
No. of
Terminal
Wires per
Wire Size
Terminal
Range
#12 to #8
1
#12
2
#10
2
#6
1
#4
1
#12 to #8
1

Solid
Wire

Stranded
Wire

X
X
X
X
—
X

X
X
X
X
X
—

#10 to #2

1

—

X

#12 to #8

1

X

X

#12

2

X

X

#10
#6
#4
#12 to #8

2
1
1
1

X
X
—
X

X
X
X
—

#10 to #2

1

—

X

#12 to #8
#10 to #2
#12 to #8

1
1
1

X
—
X

—
X
—

#10 to #2

1

—

X

Blocks and Holders

Terminal Selection Guide
Terminal Designation

150

Terminal Description

A

Copper Crimp

B

Copper Crimp

C

Copper Crimp

D

Copper Crimp

J

Copper Set Screw

Y (2 terminals)

“Y” Style Copper Set Screw

Number of Wires per Terminal

Wire Range

Wire Type

1
2
2
1
1
2
1
2
1
1
2
1
1

#12-#8
#12
#10
#6
#4
#8
#4
#6
#2
#12-#8
#10-#2
#12-#8
#10-#2

Solid/Stranded
Solid/Stranded
Solid/Stranded
Solid/Stranded
Stranded
Solid/Stranded
Stranded
Solid/Stranded
Stranded
Solid
Stranded
Solid
Stranded

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Miscellaneous Products

© 2005 Littelfuse • POWR-GARD™ Products Catalog

LPS Series POWR-Switch

152-153

LPMP Series POWR-Switch Panel

154-155

Disconnect Switches

156

Misc. Products - Fuse Reducers

157

Box Cover Units

158-159

Misc. Products - Electronic Fuse Display; Spare Fuse Cabinet

160

www.littelfuse.com

Miscellaneous Products

LPS Series POWR-Switch

The Littelfuse POWR-Switch provides a simple and economical
solution for applications that require selective coordination and shunt
trip capabilities. Common applications include elevator circuits, data
processing rooms, and building emergency systems.
By utilizing Class J time-delay fuses, the POWR-Switch is easily
coordinated with other system overcurrent devices. The shunt trip
capability allows the POWR-Switch to meet the ANSI/ASME standard
that requires power to be automatically disconnected before water is
turned on by the fire safety system. The POWR-Switch also features
pre-wired control circuits that can help reduce installation costs.

Standard Features
•
•
•
•
•
•
•

600V 3-pole fuse power switch
200,000 RMS interrupting rating
Shunt trip 120V
Control power terminal block
Ground lug per NEC
Class J fuse block
NEMA 1 enclosures

Optional Features
•
•
•
•
•
•

Misc. Products

Control power transformer with fuses and blocks
Fire safety interface relay
Key to test switch
Pilot light ”On”
Isolated neutral lug
Mechanical interlock auxilliary contact for hydraulic elevators with
automatic recall (5 amp 120 VAC rated)
• Fire alarm voltage monitoring relay
• NEMA 3R, 4, and 12 enclosures

Benefits
•
•
•
•
•
•
•

152

Optional features offer flexibility for a variety of applications
UL Listed package
Lower installation costs than systems with many separate components
Pre-wired control circuits lower installation time
Lockable Operating handle meets all code and safety requirements
No confusion over which building trade is supplying the components
POWR-Switch is a single unit, which makes procurement easier than
systems with multiple components

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Miscellaneous Products

LPS Series POWR-Switch

Ordering Information
Complete catalog numbers consist of switch catalog numbers and the desired options. See example below.

Example Catalog Number:
LPS1

T48

R1

K

Control Power
Littelfuse
Transformer
Fire Safety
Switch Catalog Std. 100VA with
Interface Relay
Number
PRI & SEC Fuse (3PDT, 10amp, 120V)
(120V Sec.)
Catalog
Option
Rating Rating
No.
Code

Rating

N1

U

Key to
Test Switch

=

Pilot Light
“ON”

30A

208V

T20

24 VDC Coil

R2

LPS6

60A

240V

T24

120 VAC Coil

R1

LPS1

100A 480V

T48

LPS2

200A 600V

T60

LPS4

400A

120V

K

Mechanical
Interlock Auxilliary Fire Alarm Voltage
Contact for Hydraulic Monitoring Relay
Elevators w/
(To Monitor Shunt
Automatic Recall
Trip Voltage)
(5 amp 120 VAC rated)

Isolated
Neutral Lug

Option
Option
Option
Rating
Rating
Code
Code
Code

LPS3

Littelfuse Catalog Number LPS1T48R1KN1U

Optional
Enclosures

Rating

Option
Code

Rating

Option
Code

Rating

Option
Code

Rating

Option
Code

Red

R

30–60A

N6

1 NO & 1 NC

A

Single Pole

F1

NEMA 3R

U

Green

G

100A

N1

2 NO & 2 NC

B

Three Pole

F3

NEMA 4

Y

White

W

200A

N2

NEMA 12

Z

400A

N4

Note: Desired options must appear in the order shown above. Typical options include Control Power Transformer, Fire Safety Interface Relay, Mechanical Interlock Auxiliary Contact
and Fire Alarm Voltage Monitoring Relay.

Enclosure Dimensions
Amp Rating

NEMA 1 Dimensions

NEMA 3R Dimensions

NEMA 4, 12 Dimensions

Lug Size

LPS3
LPS6
LPS1
LPS2
LPS4

30
60
100
200
400

24”H x 20”W x 9”D
24”H x 20”W x 9”D
24”H x 20”W x 9”D
30”H x 20”W x 9”D
48”H x 36”W x 12”D

24”H* x 20”W x 8”D
24”H* x 20”W x 8”D
24”H* x 20”W x 8”D
30”H* x 20”W x 8”D
Contact Factory

24”H x 20”W x 10”D
24”H x 20”W x 10”D
24”H x 20”W x 10”D
30”H x 20”W x 10”D
Contact Factory

#14 - #8 AL or CU
#14 - #2 AL or CU
#8 - 1/0 AL or CU
#6 - 250kcmil AL or CU
3/0 AL or CU

Misc. Products

Catalog Series

Note: Over-size enclosures used to accomodate control power transformer, interface relay and terminal blocks.
*For NEMA 3R enclosures add 2 inches to height for mounting tabs.

Specifications
Approvals:
UL Listed and CSA Certified
Rating:
30A, 60A, 100A, 200A, 400A
Shunt Trip Ratings:
Amp Rating

Voltage Rating

Max Inrush

Max Ontime

Momentary Inrush

30–400A

120V, 60Hz

4A

1.5 cycles

140VA

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

153

Miscellaneous Products

LPMP Series POWR-Switch Panel
600 Volts • Shunt-Trip Disconnect Switch
Littelfuse LPMP series POWR-Switch Panel is designed specifically
for applications that require shunt-trip capabilities and the need to
individually control power for a bank of equipment. The POWR-Switch
Panel offers the flexibility to incorporate multiple switches into a panel
enclosure and meet all applicable code requirements.

Standard Features

NEW

•
•
•
•

UL Listed Package
NEMA 1 Enclosure
Fusible Class J Switches (rated 30-400 amps)
200,000 amp RMS Short-Circuit Rating

Optional Features
•
•
•
•
•

Control Power Transformers
Fire Safety Interface Relay
Key to Test Switch
Pilot Light “On”
Mechanical Interlock Auxiliary Contact (for hydraulic elevators
with recall)
• Fire Alarm Voltage Monitor Relay
• NEMA 3R Enclosures

Ordering Information
Catalog Numbers
LPMP 400
LPMP 600
LPMP 800

Specifications

Misc. Products

Voltage Rating:
Short-Circuit Rating:
Ampere Ratings:
Approvals:

154

www.littelfuse.com

600V
200,000 amps RMS
400, 600, 800A
UL Listed to UL 67 Panelboards and
UL 891 Dead Front Switches

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Miscellaneous Products

LPMP Series POWR-Switch Panel
600 Volts • Shunt-Trip Disconnect Switch
Panel Spacing

Standard Panel Dimensions

Main Lugs Only

Available Space (X units)

Panel
Rating

Dimensions (in.)
HxWxD

400 A

57 x 40 x 12

600 A

73.5 x 40 x 12

26X

24X

800 A

90 x 40 x 12

38X

35X

3W

4W

18X

16X

Note: “X” Space = 13⁄8 inches (refers to height only)

6X

Accessory Bucket
Main Lug Terminal Information

4X

30A Switch

4X

30A Switch

60A Switch

Panel
Rating

Wire Range

(2)

# 6 - 300 kcmil Al or Cu

(1)

3 ⁄ 0 - 750 kcmil Al or Cu

400 A

60A Switch

600 A

4X

100A Switch

800 A

100A Switch

Bending Space

Cond.
/Phase

(2)

3 ⁄ 0 - 500 kcmil Al or Cu

(3)

3 ⁄ 0 - 500 kcmil Al or Cu

(2)

3 ⁄ 0 - 750 kcmil Al or Cu

Top/Bot.

Side

11.31"

10.00"

11.31"

10.00"

11.31"

10.00"

Note: Local codes may change minimum wire bends.

6X

200A Switch

200A Switch

6X

Accessory Bucket

12X

400A Switch

Thru-Feed Lugs

Misc. Products

Note: Main Lug Only is standard.
One Accessory bucket is required for every four switch units.

POWR-Switch Panel “Bucket” Options

4X

Conductors
Per Phase
(1)

# 14 – # 8 Al or Cu

Single 30 amp switch

4X

(1)

# 14 – # 8 Al or Cu

Twin 60 amp switches

4X

(1)

# 14 – # 2 Al or Cu

Single 60 amp switch

4X

(1)

# 14 – # 2 Al or Cu

100 ⁄ 100

Twin 100 amp switches

4X

(1)

# 8 – 1/0 Al or Cu

100 / Blank

Single 100 amp switch

4X

(1)

# 8 – 1/0 Al or Cu

200 ⁄ 200

Twin 200 amp switches

6X

(1)

# 6 – 250 kcmil Al or Cu

200 / Blank

Single 200 amp switch

6X

(1)

# 6 – 250 kcmil Al or Cu

400

Single 400 amp switch

12X

(2)

3 ⁄ 0 – 750 kcmil Al or Cu

Accessory

Contains CPT, Pilot Lights, etc.

6X

N/A

N/A

Bucket/Switch Rating

Description

Space

30 ⁄ 30

Twin 30 amp switches

30 / Blank
60 ⁄ 60
60 / Blank

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Wire Range

155

Miscellaneous Products

Disconnect Switches
Fusible/Non-fusible

Applications
Littelfuse disconnect switches are perfect for use where the National
Electrical Code requires that a separate disconnect means be located
within sight of all motor loads. Commonly used as a main switch
or distribution switches, these units are also ideal for use as safety
switches for air conditioners, pumps and compressors. The LFDS series
disconnect switches can be used with external fuse blocks, permitting
the use of Class RK1, RK5, J and CC fuses.

Features/Benefits

The LFFS series fusible switches eliminate the need for a separate
fuse block by integrating a three pole fuse holder into the switch body.
This saves precious panel space and reduces wiring time. These rodoperated devices are UL Listed and CSA Certified.

• Reduce panel costs – Compact size minimizes panel space and
reduces enclosure costs. The fusible 30 amp Class CC switch is the
smallest available in the market.
• Reduce installation time – Panel-mount or integral DIN rail-mount
allows quick and easy mounting.
• Flexible design – Optional accessories offer flexibility for various
applications.
• Protect personnel – Dead-front design and optional terminal covers
minimizes exposure to live parts.
• Lockable operator knob/handle – LFRK001 style knob meets
OSHA standard for control of hazardous energy sources. Other knobs
and handles meet IP65.

Specifications

Ordering Information

Voltage:
Interrupting Rating:
Required Screw Torque:
Ampere Ratings:
Approvals:

600VAC
10,000 amperes
16 inch pounds
30–100 Amperes
UL Listed (File No. E166081)
CSA Certified

Part Number
Description
LFFS030CC
30A Fusible Class CC Switch
LFDS030
30A Non-Fusible Switch
LFDS040
40A Non-Fusible Switch
LFDS060
60A Non-Fusible Switch
LFDS100
100A Non-Fusible Switch
Note: Handles and accessories sold separately.

Misc. Products

Accessories

LFRH001*
Red Handle
LFCB001
Add-on Contact Block (N.O.)
LFTC001
Terminal Cover (1 Pair)
LFRK001*
Red Knob
LFCB002
Add-on Contact Block (N.C.)
LFTC002
LFDS030 Terminal Cover (1 Pair)
LFBH001*
Black Handle
LFCB003
100A Add-on Contact Block (N.C.)
LFTC003
LFDS100 Terminal Cover (1 Pair)
LFBK001*
Black Knob
LFCB004
100A Add-on Contact Block (N.C.)
LFBK002**
Black Knob
LFPP001
30A Add-on Power Pole (N.O.)
SHFT002
Shaft (19.68")
LFPP002
30A Add-on Power Pole (N.C.)
SHFT003
Shaft (11.81")
SHFT005
Shaft (7.78")
Includes
mounting
hardware and standard length shaft for enclosures 3.5" through 8" deep.
*
Note: LFRH001, LFBH001, LFBK001 and LFBK002 are not lockable.
** Supplied with 2" shaft

156

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Miscellaneous Products

Miscellaneous Products
Fuse Reducers
Littelfuse fuse reducers allow smaller size fuses to be installed into
existing fuse clips to prevent overfusing.
•
•
•
•
•

Allows lower ampere-rated fuses to be used in existing fuse clips.
Simple installation.
Reduces inventory requirements.
Silver brazed joints for maximum strength.
UL Listed (File No. E136855) CSA Certified (File No. LR92899)

Refer to fuse section of this catalog for fuse dimensions.

250 Volt

Class H/K5
Fuse Reducers
For use with Littelfuse NLN/NLS
and RLN/RLS series fuses.

600 Volt

Part No. (pair)

Fuse Clip

Fuse Case Size

Part No. (pair)

Fuse Clip

Fuse Case Size

LRU 263 M
LRU 213 M
LRU 216
LRU 226
LRU 2621
LRU 2641
LRU 2642
LRU 2661
LRU 2662
LRU 2664

60A
100A
100A
200A
200A
400A
400A
600A
600A
600A

30A
30A
60A
60A
100A
100A
200A
100A
200A
400A

LRU 663 M
LRU 216
LRU 616
LRU 626
LRU 2621
LRU 2641
LRU 2642
LRU 2661
LRU 2662
LRU 2664

60A
100A
100A
200A
200A
400A
400A
600A
600A
600A

30A
30A
60A
60A
100A
100A
200A
100A
200A
400A

Fuse Case Size

Part No. (pair)

250 Volt

Class R
Fuse Reducers

Fuse Clip

LRU 263 R
60A
LRU 213 R
100A
LRU 216 R
100A
LRU 226 R
200A
LRU 2621 R
200A
LRU 2641 R
400A
LRU 2642 R
400A
LRU 2661 R
600A
LRU 2662 R
600A
*LRU 2664 R
600A
* Only one reducer required.

600 Volt
30A
30A
60A
60A
100A
100A
200A
100A
200A
400A

Fuse Clip

LRU 663 R
60A
LRU 216 R
100A
LRU 616 R
100A
LRU 626 R
200A
LRU 2621 R
200A
LRU 2641 R
400A
LRU 2642 R
400A
LRU 2661 R
600A
LRU 2662 R
600A
*LRU 2664 R
600A
* Only one reducer required.

Fuse Case Size
30A
30A
60A
60A
100A
100A
200A
100A
200A
400A

Misc. Products

For use with Littelfuse FLNR_ID/
FLSR_ID, IDSR, LLNRK/LLSRK,
LLSRK_ID, and KLNR/KLSR
series fuses.

Part No. (pair)

600 Volt

Class J
Fuse Reducers
For use with Littelfuse JTD_ID/
JTD and JLS series fuses.

Part No. (pair)

Fuse Clip

Fuse Case Size

LRUJ63
LRUJ13
LRUJ16*
LRUJ26
LRUJ21
LRUJ41
LRUJ42
LRUJ64

60A
100A
100A
200A
200A
400A
400A
600A

30A
30A
60A
60A
100A
100A
200A
400A

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

* Fuse and reducer combination is slightly larger in diameter than
100A Class J fuses. For specific applications, contact factory.
Class J reducers can not be used in bolt-on applications.

157

Miscellaneous Products

Box Cover Units

Box cover units provide an economical method of protecting small
motors against overcurrent damage. For use with Edison-Base plug
fuses (TOO, TLO) or Type S plug fuses (SOO, SLO) with adapters (SAO).

Specifications
Voltage:
Ampere Rating:
Approvals:

Fig. No. Littelfuse Part No.

125V
15 Amperes
UL Listed

Box Cover Features

To Be Mounted On:

LSOU

One Edison-Base Fuse Holder

21⁄4" Handy Box

LSOW

One Edison-Base Fuse Holder

2 3 ⁄ 4" Switch Box

LSOX

One Edison-Base Fuse Holder

4" Octagon Box

LSOY

One Edison-Base Fuse Holder

4" Square Box

LSRU

One Edison-Base Fuse Holder and Grounding Receptacle

2 1⁄4" Handy Box

LSRW

One Edison-Base Fuse Holder and Grounding Receptacle

2 3 ⁄ 4" Switch Box

LSRX

One Edison-Base Fuse Holder and Grounding Receptacle

4" Octagon Box

LSRY

One Edison-Base Fuse Holder and Grounding Receptacle

4" Square Box

LSSU

One Edison-Base Fuse Holder and Single Pole Switch

21⁄4" Handy Box

LSSW

One Edison-Base Fuse Holder and Single Pole Switch

2 3 ⁄ 4" Switch Box

LSSX

One Edison-Base Fuse Holder and Single Pole Switch

4" Octagon Box

LSSY

One Edison-Base Fuse Holder and Single Pole Switch

4" Square Box

4

LSOY-B

Two Edison-Base Fuse Holders

4" Square Box

5

LSSY-L

One Edison-Base Fuse Holder
One Single Pole Switch and Pilot Light

4" Square Box

6

LSSY-RL

One Edison-Base Fuse Holder
One Grounding Receptacle
One Single Pole Switch and Pilot Light

4" Square Box

7

LSCY

Two Edison-Base Fuse Holders and Two Single Pole Switches

4" Square Box

8

LSKA

Two Edison-Base Fuse Holders
One 250V Grounding Receptacle

4 11 ⁄ 16" Square Box

9

LSTY

Two Edison-Base Fuse Holders and One 2-Pole Switch

4" Square Box

11

2

Misc. Products

3

158

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Miscellaneous Products

Box Cover Units

2-1/ 4” Handy Box

4” Handy Box

LSOU

LSOW

LSOY

LSOY-B

LSRU

LSRW

LSRY

LSCY

LSSU

LSSW

LSSY

LSTY

Misc. Products

LSSY-L

LSSY-RL

3 1⁄ 2” Octagonal Box

LSOX

LSRX

© 2005 Littelfuse • POWR-GARD™ Products Catalog

LSSX

www.littelfuse.com

4 1⁄ 2” Box
LSKA

159

Miscellaneous Products

Misc. Products
Electronic Fuse Display • Spare Fuse Cabinet
Spare Fuse Cabinet
Sturdy steel cabinet holds spare fuses. Cabinet can be locked to prevent
unauthorized access and is weather stripped to reduce the accumulation of dust, dirt and moisture. Convenient inventory card located inside
door. Measures 30" H × 24" W × 12" D. Keyhole mounting holes 16" on
center for easy installation.

Ordering Information
Spare Fuse Cabinet:
Spare Keys:

Part No. LSFC
Part No. LKEY001

Electronic Fuse Display

Misc. Products

The sturdy wall-mountable or free-standing modular rack system
prominently displays the most popular Littelfuse glass and automotive
fuses. Additional sections can be quickly snapped on to provide a larger
product selection. Each rack features a cross reference and full color
identification guide to help customers locate the proper replacement fuse.
• Holds 720 (144 5-packs) of the most popular glass, ceramic, and
automotive fuses.
• Designed to save space—measures 14" H × 9" W × 4" D.
• Suitable for wall or counter mounting.
• Includes cross reference, product identification guide, and back-up
card for easy reordering.
• Expandable with modular section that can hold 240 fuses
(48 5-packs) per section.

Ordering Information
Fully stocked display: Littelfuse part number: 094324PG
Littelfuse system number: 00940324ZXPG
Empty display rack:
Littelfuse part number: FDR001PG
Littelfuse system number: 0FDR0001ZXPG
Additional sections: Littelfuse part number: MRS001PG
Littelfuse system number: 0MRS0001ZXPG
Fully stocked rack includes the following parts:
3AG (Glass)
Fast Acting Fuses
Quantity
Part No.
25
312 1⁄2 A
50
312 1A
25
312 11⁄2 A
75
312 2A
25
312 2 1⁄ 2 A
75
312 3A
25
312 4A
25
312 5A
25
312 10A

160

3AG (Glass)
Slo-Blo® Fuses
Quantity
Part No.
25
313 1⁄2 A
25
313 3 ⁄ 4 A
25
313 1A
25
313 11⁄2 A
50
313 2A
25
313 2 1⁄2 A
25
313 3A
25
313 4A
25
313 5A

3AB (Ceramic)
Normal-Blo Fuses
Quantity
Part No.
25
314 15A
25
314 20A
25
314 30A

www.littelfuse.com

3AB (Ceramic)
Slo-Blo® Fuses
Quantity
Part No.
25
326 8A
20
326 10A

© 2005 Littelfuse • POWR-GARD™ Products Catalog

International Products

© 2005 Littelfuse • POWR-GARD™ Products Catalog

LgD Series Global Pro™ Fuses

162

LPSG Series Global Pro™ Fuseholders

163

NH Fuse Links

164-165

Diazed/Neozed Fuses

166-167

Cylindical Fuses

168

British Dimension HRCII-C Fuses

169

www.littelfuse.com

International Products

LgD Series Global Pro™ Fuses
600 Volts AC • Time-Delay • 1 – 100 Amperes

Applications
•
•
•
•

Motor control centers
Motor branch circuits
Primary and secondary protection for transformers
Equipment designed for export

Features And Benefits
The Global Pro fuse is physically compatible with IEC style fuseholders
allowing it to be used in virtually any market. The IEC dimensions of the
Global Pro fuseholder allow easy adaptation of exported equipment by
simply replacing the fuse with one that meets local standards.

Littelfuse Global Pro is the world’s only fuse system designed for use
anywhere, in any equipment, in virtually any country. Global Pro simplifies
circuit protection by incorporating North American electrical requirements
into fuse styles found in the rest of the world. Reduced size, touch-safe
design, and international acceptance make the Global Pro system the easy
circuit protection choice for engineers and equipment designers everywhere.
Global Pro fuses provide quick and positive visual identification of blown
fuses by using a pop-up indicator design that protrudes from the top of
the fuse, immediately alerting maintenance personnel that it needs to
be replaced. The pop-up indicator is designed to activate a microswitch
built into every Global Pro fuseholders that can activate stack-lights or
to integrate into PLC networks and provide equipment operators with a
remote method of determining when the fuse needs to be replaced.

•
•
•
•
•
•
•
•
•
•

Extremely compact size
Pop-up pin indication
Meets performance requirements of UL Class J fuses
Global acceptance
UL approval
Universal voltages
Touch-safe components
Integrated lockout/tagout device for compliance
Design versatility for OEMs
Designed to IEC standards

Size Chart
Part Number
LgD 0–30A
LgD 35–60A
LgD 70–100A

Amperage
0–30A
35–60A
70–100A

English
⁄ ” x 2”
13 16
⁄ ” x 2 1⁄ 4”
11⁄16” x 2 3 ⁄ 8”
9 16

Metric
14mm x 51mm
22mm x 58mm
27mm x 60mm

International Products

The Global Pro system is designed to save valuable space in a crowded
panel while providing designers with the flexibility of a universally
accepted design for easy replacement. These fuses are far more
compact and have greater power handling capability than conventional
products. Global Pro fuses are up to 75% smaller than Class RK5 fuses
and up to 50% smaller than Class J fuses while providing the time-delay
characteristics that are necessary for motor circuit protection.

Specifications
Voltage Ratings:

Interrupting Rating:
Ampere Range:
Approvals:

162

Ampere ratings
AC: 600 Volts (UL)
690 Volts (IEC)
DC: 300 Volts
AC:
200,000 amperes rms symmetrical
DC: 20,000 amperes rms symmetrical
1 – 100* amperes
UL Listed Special Purpose 1–30 amps
(File No. E71611)
UL Recognized 35–60 amps (File No. E71611)
CSA Certified 1–60 amps (File No. LR29862)

1
2
3

5
7
10

12
15
20

25
30
35

40
45
50

60
70*
80*

90*
100*

*Contact factory for ratings above 60A
Example part number (series & amperage): LgD 60

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

International Products

LPSG Series Global Pro™ Fuseholders

Applications
•
•
•
•

Motor control centers
Motor branch circuits
Primary and secondary protection for transformers
Equipment designed for export

Features And Benefits
The Global Pro Fuseholder also accepts IEC dimension cartridge style
fuses, allowing equipment to be easily adapted for export markets by
simply replacing the fuse with one that meets local standards.

Littelfuse Global Pro is the world’s only fuse system designed for
use anywhere, in any equipment, in virtually any country. Global Pro
simplifies circuit protection by incorporating North American electrical
requirements into fuse styles found in the rest of the world. Reduced
size, touch-safe design, and international acceptance make the Global
Pro system the easy circuit protection choice for engineers and
equipment designers everywhere.
Every Global Pro fuseholder includes a microswitch that is activated by
a blown fuse. This allows the Global Pro system to be integrated into
PLC networks and provide equipment operators with a remote method
of determining when the fuse needs to be replaced. Global Pro holders
also feature a blown fuse indicator light to help maintenance personnel
quickly locate the proper circuit.
The Global Pro system is designed to save valuable space in a crowded
panel, while providing designers with the flexibility of a universally
accepted design for easy replacement. These fuses are far more
compact and have greater power handling capability than conventional
products. Global Pro fuses are up to 75% smaller than Class RK5 fuses
and up to 50% smaller than Class J fuses while providing the time-delay
characteristics that are necessary for motor circuit protection.

•
•
•
•
•
•

Extremely compact size
Blown fuse indicator
Integrated lockout/tagout tab
Din-Rail mountable (35mm DIN-Rail)
Integrated microswitch with N.O. and N.C. contacts
Global compatibility – Accepts Global Pro fuses and European IEC
dimension cartridge style fuses
• UL and IEC approval
• Touch-safe design with integrated lockout/tagout device for
compliance
• Design versatility for OEMs

Ordering Information
Catalog No.

Amp Rating

Poles

LPSG30-1MI
LPSG30-2MI
LPSG30-3MI
LPSG60-1MI
LPSG60-2MI
LPSG60-3MI
LPSG100-1MI
LPSG100-2MI
LPSG100-3MI

30A
30A
30A
60A
60A
60A
100A
100A
100A

1
2
3
1
2
3
1
2
3

International Products

Specifications
Voltage Ratings:
Interrupting Rating:
Ampere Range:
Terminal Type:
Wire Range:
Material:

600 Volts (UL)
690 Volts (IEC)
AC:
200kA rms symmetrical
DC: 20kA
30, 60, and 100* amperes
Pressure Plate
#2 – #14 CU
Thermo-plastic

Approvals:

UL Recognized
CSA Certified
*Contact factory for ratings above 60A

Contact factory for dimensions.
© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

163

International Products

NH Fuse Links
500 Volts • 2 – 630 Amperes
Littelfuse European style NH fuse links are designed for the protection of conductors and
motors. The gL-gG characteristic fuse links are generally used to protect cables and installation
lines from overloads and short-circuits. The aM characteristic fuse links are used for the shortcircuit protection of motors and switchgear. They are available in NH00C to NH3 sizes up to 630
amperes.

Specifications
Standards:
Approvals:
Example part number:

DIN 43.620, IEC 269-2-1
VDE
NH1CG25 (size, characteristic and amperage)

Size

Current Range

Voltage
(AC/DC)

Interrupting
Rating

Nominal
Frequency

Selectivity

00C
00
0
1C
1
2C
2
3C
3

2A up to 100A
2A up to 160A
6A up to 160A
25A up to 160A
63A up to 250A
40A up to 250A
125A up to 400A
315A up to 400A
315A up to 630A

500V/440V
500V/440V
500V/440V
500V/440V
500V/440V
500V/440V
500V/440V
500V/440V
500V/440V

120kA/25kA
120kA/25kA
120kA/25kA
120kA/25kA
120kA/25kA
120kA/25kA
120kA/25kA
120kA/25kA
120kA/25kA

45 - 62 Hz
45 - 62 Hz
45 - 62 Hz
45 - 62 Hz
45 - 62 Hz
45 - 62 Hz
45 - 62 Hz
45 - 62 Hz
45 - 62 Hz

1:1 25
1:1 25
1:1 25
1:1 25
1:1 25
1:1 25
1:1 25
1:1 25
1:1 25

All NH fuse links incorporate a blown fuse indicator.

gL-gG 500V

Amperage

International Products

2
4
6
10
16
20
25
32
35
40
50
63
80
100
125
160
200
224
250
300
315
355
400
425
500
630

164

NH00C/NH00
NH00CG2
NH00CG4
NH00CG6
NH00CG10
NH00CG16
NH00CG20
NH00CG25
NH00CG32
NH00CG35
NH00CG40
NH00CG50
NH00CG63
NH00CG80
NH00CG100
NH00G125
NH00G160
—
—
—
—
—
—
—
—
—
—

NH0
—
—
NH0G6
NH0G10
NH0G16
NH0G20
NH0G25
NH0G32
NH0G35
NH0G40
NH0G50
NH0G63
NH0G80
NH0G100
NH0G125
NH0G160
—
—
—
—
—
—
—
—
—
—

NH1C/NH1
—
—
—
—
—
—
NH1CG25
NH1CG32
NH1CG35
NH1CG40
NH1CG50
NH1CG63
NH1CG80
NH1CG100
NH1CG125
NH1CG160
NH1G200
NH1G224
NH1G250
—
—
—
—
—
—
—

aM 500V
NH2C/NH2
—
—
—
—
—
—
—
—
—
NH2CG40
NH2CG50
NH2CG63
NH2CG80
NH2CG100
NH2CG125
NH2CG160
NH2CG200
NH2CG224
NH2CG250
NH2G300
NH2G315
NH2G355
NH2G400
—
—
—

NH3C/NH3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
NH3CG315
NH3CG355
NH3CG400
NH3G425
NH3G500
NH3G630

www.littelfuse.com

NH00M
NH00M2
NH00M4
NH00M6
NH00M10
NH00M16
NH00M20
NH00M25
NH00M32
NH00M35
NH00M40
NH00M50
NH00M63
NH00M80
NH00M100
NH00M125
NH00M160
—
—
—
—
—
—
—
—
—
—

NH1
—
—
—
—
—
—
—
—
—
—
—
NH1M63
NH1M80
NH1M100
NH1M125
NH1M160
NH1M200
NH1M224
NH1M250
—
—
—
—
—
—
—

NH2
—
—
—
—
—
—
—
—
—
—
—
—
—
—
NH2M125
NH2M160
NH2M200
NH2M224
NH2M250
NH2M300
NH2M315
NH2M355
NH2M400
—
—
—

NH3
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
NH3M315
NH3M355
NH3M400
—
NH3M500
NH3M630

© 2005 Littelfuse • POWR-GARD™ Products Catalog

International Products

NH Fuse Links

NH Fuse Link Dimensions

C

D

B
A
Size

Current Range

00C
00
0
1C
1
2C
2
3C
3

2-100A
2-160A
6-160A
25-160A
63-250A
40-250A
125-400A
315-400A
315-630A

A
78.00
78.00
123.95
135.00
135.00
150.00
150.00
150.00
150.00

Dimensions (mm)
B
C
54.00
51.30
54.00
56.40
70.11
53.34
75.00
56.40
75.00
64.30
75.00
64.26
75.00
74.20
75.00
74.20
75.00
87.37

D
20.00
30.00
30.00
30.00
40.00
40.00
50.00
50.00
71.88

NH Bases / Disconnects
Fuse Bases
Size

Rating

Connection

NHB00B
NHB00C
NHB1B
NHB2B
NHB3B

00
00
1
2
3

690V/160A
690V/160A
690V/250A
690V/400A
690V/630A

Bolt
V-Clamp
Bolt
Bolt
Bolt

International Products

Part No.

All fuse bases are single pole and gangable.

Fuse Disconnects
Part No.

Size

Rating

Connection

NHFSC00B
NHFS0B
NHFS1B
NHFS2B
NHFS3B

C00
0
1
2
3

690V/100A
690V/160A
690V/250A
690V/400A
690V/630A

Bolt
Bolt
Bolt
Bolt
Bolt

All disconnects are 3 pole.
Contact factory for dimensional information.
© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

165

International Products

Diazed/ Neozed Fuses
380-500 Volts AC • 2 – 63 Amperes
Littelfuse fast acting (gL-gG) fuses are used for the protection of cables
against short-circuits. Time-lag (aM) fuses are used for protection of
motors. Ratings are available in standard Diazed and compact Neozed
styles.

Specifications
Standards:
DIN 49.522-DIN 49.525, IEC 269-3
Approvals:
VDE
Example part number: DZ27F4
Base Size

Type

14
18
16
27
33

D01
D02
DI
DII
DIII

Current Range Voltage AC/DC
2-16A
20-63A
2-25A
2-25A
35-63A

380V/250V
380V/250V
500V
500V
500V

Interrupting
Rating
50kA
50kA
80kA
80kA
80kA

All Diazed and Neozed fuses incorporate a blown fuse indicator.

Diazed Fuses

Neozed Fuses
11

36

13.2

15

36

A

21.5

50

27

50

A

50

A

A

A

D01

D02

DI

DII

DIII

International Products

All dimensions are in “mm”

Diazed Fuses
Amperage
Color
2
Pink
4
Brown
6
Green
10
Red
16
Grey
20
Blue
25
Yellow
35
Black
50
White
63
Copper
Base Size (mm)

166

DI
DZ16F2
DZ16F4
DZ16F6
DZ16F10
DZ16F16
DZ16F20
DZ16F25
—
—
—
16

gL-gG
DII
DZ27F2
DZ27F4
DZ27F6
DZ27F10
DZ27F16
DZ27F20
DZ27F25
—
—
—
27

DIII
—
—
—
—
—
—
—
DZ33F35
DZ33F50
DZ33F63
33

DI
DZ16T2
DZ16T4
DZ16T6
DZ16T10
DZ16T16
DZ16T20
DZ16T25
—
—
—
16

Neozed Fuses
aM
DII
DZ27T2
DZ27T4
DZ27T6
DZ27T10
DZ27T16
DZ27T20
DZ27T25
—
—
—
27

www.littelfuse.com

DIII
—
—
—
—
—
—
—
DZ33T35
DZ33T50
DZ33T63
33

DIM.
A (mm)
6
6
6
8
10
12
14
16
18
20
—

gL-gG
D01
D0Z14G2
D0Z14G4
D0Z14G6
D0Z14G10
D0Z14G16
—
—
—
—
—
14

D02
—
—
—
—
—
D0Z18G20
D0Z18G25
D0Z18G35
D0Z18G50
D0Z18G63
18

DIM.
A (mm)
7.3
7.3
7.3
8.5
9.7
10.9
12.1
13.3
14.5
15.9
—

© 2005 Littelfuse • POWR-GARD™ Products Catalog

International Products

Diazed/ Neozed Fuses

Fuse bases, carriers, and gauge rings are available for Diazed (DZ) and
Neozed (D0Z) type fuses. Fuse holders are comprised of a fuse base
and carrier. Optional gauge rings act as a rejection feature and are used
to prevent over-sizing of fuses. All bases and carriers are single pole
units. Contact factory for additional information.

Fuse Bases
Part No.

Fuse Type

Base Size (mm)

Mounting Type

DZB27S
DZB27DR
DZB33S
DZB33DR
D0ZB14S
D0ZB14DR
D0ZB18S
D0ZB18DR

DZ
DZ
DZ
DZ
D0Z
D0Z
D0Z
D0Z

27
27
33
33
14
14
18
18

Screw
Din Rail
Screw
Din Rail
Screw
Din Rail
Screw
Din Rail

Fuse Carriers
Part No.

Fuse Type

Base Size (mm)

DZC27
DZC33
D0ZC14
D0ZC18

DZ
DZ
D0Z
D0Z

27
33
14
18

Gauge Rings
Color

DZ

DZ

D0Z

D0Z

Pink
Brown
Green
Red
Grey
Blue
Yellow
Black
White
Copper

DZ27PK
DZ27BR
DZ27GN
DZ27RD
DZ27GY
DZ27BE
DZ27YW
—
—
—

—
—
—
—
—
—
—
DZ33BK
DZ33WE
DZ33CR

D0Z14PK
D0Z14BR
D0Z14GN
D0Z14RD
—
—
—
—
—
—

D0Z18PK
D0Z18BR
D0Z18GN
D0Z18RD
D0Z18GY
D0Z18BE
D0Z18YW
D0Z18BK
D0Z18WE
—

International Products

Amp
Rating
2
4
6
10
16
20
25
35
50
63

Contact factory for dimensional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

167

International Products

Cylindrical Fuses
500 Volts • 0.5 – 100 Amperes
Littelfuse fast acting (gL-gG) fuses are used for the protection of cables
against short-circuits. Time-lag (aM) fuses are used for protection of
motors.

Specifications
Standards:
Example part number:

IEC 269-2-1
CY22X58G50

Size

Current Range

Voltage AC

Interrupting Rating

10 x 38 mm
14 x 51 mm
22 x 58 mm

0.5-32A
2-50A
16-100A

500V
500V
500V

120kA
80kA
80kA

B

A

gL-gG

International Products

Amperage
0.5
1
2
4
6
8
10
12
16
20
25
32
40
50
63
80
100
Dimensions
A
(mm)
B

10X38
CY10X38G.5
CY10X38G1
CY10X38G2
CY10X38G4
CY10X38G6
CY10X38G8
CY10X38G10
CY10X38G12
CY10X38G16
CY10X38G20
CY10X38G25
CY10X38G32
—
—
—
—
—
10
38

aM

14X51
—
—
CY14X51G2
CY14X51G4
CY14X51G6
CY14X51G8
CY14X51G10
CY14X51G12
CY14X51G16
CY14X51G20
CY14X51G25
CY14X51G32
CY14X51G40
CY14X51G50
—
—
—
14
51

22X58
—
—
—
—
—
—
—
—
CY22X58G16
CY22X58G20
CY22X58G25
CY22X58G32
CY22X58G40
CY22X58G50
CY22X58G63
CY22X58G80
CY22X58G100
22
58

10X38
CY10X38M.5
CY10X38M1
CY10X38M2
CY10X38M4
CY10X38M6
CY10X38M8
CY10X38M10
CY10X38M12
CY10X38M16
CY10X38M20
CY10X38M25
CY10X38M32
—
—
—
—
—
10
38

Fuseholders
Part No.
Size # of Poles Amp Rating
CYH10381
10X38
1
32A
CYH10382
10X38
2
32A
CYH10383
10X38
3
32A
CYH10381ID* 10X38
1
32A
CYH14511
14X51
1
50A
CYH14512
14X51
2
50A
CYH14513
14X51
3
50A
CYH22581
22X58
1
125A
CYH22582
22X58
2
125A
CYH22583
22X58
125A
3
* Indicating
NOTE: All fuseholders are DIN-Rail mountable.
Contact factory for dimensional information.

168

14X51
—
—
CY14X51M2
CY14X51M4
CY14X51M6
CY14X51M8
CY14X51M10
CY14X51M12
CY14X51M16
CY14X51M20
CY14X51M25
CY14X51M32
CY14X51M40
CY14X51M50
—
—
—
14
51

22X58
—
—
—
—
—
—
—
—
CY22X58M16
CY22X58M20
CY22X58M25
CY22X58M32
CY22X58M40
CY22X58M50
CY22X58M63
CY22X58M80
CY22X58M100
22
58

Multi-pole Assembly Kit
Voltage
690V
690V
690V
690V
690V
690V
690V
690V
690V
690V

Terminal Type
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate
Pressure Plate

www.littelfuse.com

Assembly kit is designed for use with
CYH1038 and LPSC/LPSM fuse holders.
Kit contains 20 connector pincers and 10
handle pins.
Part No: CYHP001

© 2005 Littelfuse • POWR-GARD™ Products Catalog

International Products

British Dimension HRCII-C Fuses
600 Volts AC • 2– 600 Amperes

Specifications
Voltage Rating:
Interrupting Rating:

600 Volts AC, 250 Volts DC
200,000 amperes rms symmetrical AC
80,000 amperes rms symmetrical DC
2 – 600 amperes
CSA Certified to Standard C22.2 No. 106-M90
(File No. LR90341)

Ampere Range:
Approvals:

Ampere ratings
2CO

2
4
6

10
15
20

25
30
40

50
60

80
100

2CC

125
150

200
250

300
350

400
450

500
600

2CM

80
100

125
150

200
250

300
350

400

Example part number (series & amperage): 2CM 150

HRCII-C fuses are stud-mounted fuses designed to British standard
dimensions. They are generally used for motor short-circuit protection in
dead-front holders, and are normally required to be used in conjunction
with a motor running overload device.

Recommended Fuse Blocks
DF30 (F, B, FB) — Fits 2 – 30 amps
DF60 (F, B, FB) — Fits 40 – 60 amps
DF100 (F, B, FB) — Fits 80 – 100 amps
For additional information on HRCII-C fuse holders, contact factory.

D
G
A

D
G
A
B

B
H

F

E

J

J
F

FIG. 1

FIG. 2
G

K
E
H

Cat. No.

Old LF
Part No.

Refer To
Fig. No.

2CO 2-30
2CO 40-60
2CO 80-100
2CC 125-200
2CC 250-400
2CC 450-600
2CM 80-100
2CM 125-200
2CM 250-400

FII
FII
FII
FIIC
FIIC
FIIC
FIIM
FIIM
FIIM

1
1
1
2
3
3
2
1
2

International Products

FIG. 3

Dimensions in mm (inches in parentheses)
A
56 (2.2)
57 (2.24)
68 (2.88)
76 (3)
81 (3.19)
83 (3.27)
66 (2.6)
77 (3.03)
81 (3.19)

21
26
36
41
58
74
31
41
58

B
(0.83)
(1.02)
(1.42)
(1.61)
(2.28)
(2.91)
(1.22)
(1.81)
(2.25)

C
—
—
—
—
—
—
—
—
—

D
85 (3.3)
88 (3.45)
110 (4.33)
137 (5.39)
210 (8.27)
210 (8.27)
135 (5.31)
110 (4.33)
136 (5.35)

E
9 (0.35)
13 (0.51)
19 (0.75)
19 (0.75)
26 (1.02)
26 (1.02)
19 (0.75)
19 (0.75)
26 (1.02)

F
1 (0.04)
1.6 (0.06)
2.4 (0.09)
3.6 (0.14)
6.5 (0.26)
6.5 (0.25)
3.6 (0.14)
2.4 (0.09)
5.2 (0.2)

G
73 (2.87)
73 (2.87)
94 (3.7)
111 (4.37)
133 (5.24)
133 (5.24)
111 (4.37)
94 (3.7)
111 (4.37)

H
5.5 (0.21)
5.5 (0.21)
8.7 (0.34)
8.7 (0.34)
10.3 (0.4)
10.3 (0.4)
8.7 (0.34)
8.7 (0.34)
8.7 (0.34)

J
7.5 (0.29)
7.5 (0.29)
—
16 (0.63)
16 (0.63)
16 (0.63)
16 (0.63)
10.3 (0.4)
16 (0.63)

K
—
—
—
—
25.4 (1)
25.4 (1)
—
—
—

*Hole diameter to accept insulated stud (types C and D) mm min

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

169

Suppression Products

Overvoltage Suppression Products: Introduction

171-172

Industrial Varistor Products

173

Surge Suppression Fuses

174

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Suppression Products

Overvoltage Suppression Products
Introduction
Overvoltage conditions are rapidly becoming an increasing concern
in the electrical industry. Component miniaturization has resulted in
increased sensitivity to many devices as the trend towards downsizing
equipment and components continues. The majority of these devices
are unable to handle high currents that result from Electrostatic
Discharge (ESD) and other voltage transients.

Did you know?
• 75% of field equipment failure is caused by
Electrical Over-Stress (EOS)
• Semiconductor devices are becoming increasingly
intolerant to voltage transients
• A lightning strike several miles away can induce
transients in your equipment
• Power distribution transformers susceptibility
impacts clean power condition

What Are Transients?
Voltage Transients are defined as short duration surges of electrical
energy. Transients result from the sudden release of previously stored
energy. In terms of electrical and electronic circuits, this energy can be
released through intentional, controlled switching action, or induced into
a circuit from external sources. If the voltage magnitude of the transient
is large enough, circuit component damage or malfunction of the circuit
may result.
Transients occur in either repeatable fashion or as random impulses.
Repeatable transients are frequently caused by the operation of motors,
generators, or the switching of reactive circuit components. Random
transients, on the other hand, are often caused by lightning and ESD.
Lightning and ESD generally occur unpredictably, and may require
elaborate monitoring to be accurately measured.

Typical Overvoltage Applications

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Lighting
Switching
EMP
SSD

www.littelfuse.com

Voltage

Current

Rise-Time

Duration

25kV
600V
1kV
15kV

20kA
500A
10A
30A

10µs
50µs
20ns
1-5ns

1ms
500ms
1ms
100ns

Suppression

Industrial, High Energy AC Products
(Solenoids, Motor Drives, Robotics, etc.)
Telecommunications Products
TVSS Products (UPS, AC Panels, Power Supplies,
Circuit Breakers, etc.)
Portable Electronic Equipment
Automotive Electronics

Transient Sources and Magnitude

171

Suppression Products

Overvoltage Suppression Products
Introduction
Transient Voltage Scenarios

MLV

The switching of inductive loads generates high energy transients
which increase in magnitude with increasingly heavy loads. When the
inductive load is switched off, the collapsing magnetic field is converted
into electrical energy which takes the form of a double exponential
transient. Depending on the source, these transients can be as large
as hundreds of volts and hundreds of amps with duration times of 400
milliseconds.
Typical sources of inductive transients are:
• Generator
• Motor
• Relay
• Transformer

Multilayer Metal Oxide Varistor
Ceramic Technology
Available in a wide range of surface mount packages. Offers a lower voltage
range and enhanced performance and filtering characteristics for applications
requiring protection from low to medium energy transients.

PulseGuard® Suppressor
Voltage Variable Polymer Technology
Available in surface mount and ‘D-Sub connector’ format packages.
Specifically designed for high data-rate applications requiring ESD
protection and the lowest possible capacitance.

TVS Diode Arrays

These examples are extremely common in electrical and electronic
systems. Because the sizes of the loads vary according to the
application, the wave shape, duration, peak current, and peak voltage
are all variables which exist in real world transients. Once these
variables can be approximated, a suitable suppressor technology can be
selected.

ESD (Electrostatic Discharge)
Electrostatic discharge is characterized by very fast rise times and
very high peak voltages and currents. This energy is the result of an
imbalance of positive and negative charges between objects.

Lightning Induced Transients
Even though a direct strike is clearly destructive, transients induced
by lightning are not the result of a direct strike. When a lightning strike
occurs, the event creates a magnetic field which can induce transients
of large magnitude in nearby electrical cables.

Technological Solutions for Transient Threats

Silicon Avalanche Diode Technology
Available in surface mount multi-pin packages or CSP (chip scale
package) arrays. Designed for applications requiring multiline ESD
protection and the lowest possible clamp voltage.

Discrete TVS Diode
Silicon Avalanche Diode Technology
Available in surface mount and axial leaded packages. Offers protection
from medium to very high energy transients and can be used in wide
range of applications.

SIDACTOR® Thyristor
Thyristor Breakover Technology
Available in surface mount, axial leaded and TO-220 through hole
package options. Offers protection from medium to high energy
transients, SIDACTOR thyristors are specifically designed for transient
suppression in telecom and data transmission systems.

Gas Plasma Protector/Gas Discharge Tube
Gas Plasma Technology
Available in surface mount, axial leaded, radial leaded and special
packages. The Littelfuse Gas Plasma technology offers high surge
ratings and very low capacitance for use in telecommunication and
broadband systems.

Because of the various types of transients and applications, it is
necessary to employ protection devices with different characteristics
in different applications. Littelfuse offers the broadest range of circuit
protection technologies. Our overvoltage protection portfolio includes:

MOVs

Suppression

Metal Oxide Varistors (MOV)
Ceramic Technology
Available in screw terminal, radial, square and axial leaded connections.
Offers medium to very high energy ratings for a wide range of
applications.

Surface Mount MOV
Metal Oxide Varistor (MOV)
Ceramic Technology
Available in a wide range of voltage ratings. Offers low to medium
energy ratings for a variety of applications and is available with screw
terminal, radial, square and axial leaded connections.

172

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Suppression Products

Overvoltage Suppression Products
Industrial Varistor Products
TMOV™/iTMOV™ UltraMov™
Varistor Series

Varistor Series

Operating Voltage:
Peak Current:
Peak Energy:
Mount/Form Factor:
Disc Size:
Indicating:

Peak Current:
Peak Energy:
Mount/Form Factor:
Disc Size:

E

®

®

D

130-320 VAC

MA Series

RA Series
®

V

E

LA Series
®

®

D

V

E

ZA Series
®

D

V

E

6,000-9,000A
45-220J
Radial Leaded
14, 20mm
N/A

130-1000 VAC
175-1200 VDC
1,200-6,500A
11-360J
Radial Leaded
7, 10, 14, 20mm
N/A

4-460 VAC
5.5-615 VDC
50-6,500A
0.1-52J
Radial Leaded
5, 7, 10, 14, 20mm
N/A

CH Series

CA Series

NA Series

®

9-264 VAC
13-365 VDC
40-100A
0.06-1.7J
Axial Leaded
3mm

4-275 VAC
5.5-369 VDC
150-6,500A
0.4-140J
Packaged
8, 6, 22mm

14-275 VAC
18-369 VDC
250-500A
1-23J
Surface Mount
N/A

250-2800 VAC
330-3500 VDC
20,000-70,000A
200-10,000J
Bare Disc
32, 40, 60mm

250-750 VAC
330-970 VDC
40,000A
370-1,050J
Bare Disc
34mm

PA Series

HB34 Series

HA Series

DA/DB Series

BB/BA Series

®

130-660 VAC
175-850 VDC
6,500A
70-250J
Packaged
20mm

®

®

®

130-750 VAC
175-970 VDC
40,000A
270-1,050J
Industrial Packaged
34mm

®

130-750 VAC
175-970 VDC
25,000-40,000A
200-1,050J
Packaged
32, 40mm

®

130-970 VAC
175-970 VDC
40,000A
270-1,050J
Industrial Packaged
40mm

®

®

D

V

E

130-2800 VAC
175-3500 VDC
50,000-70,000A
450-10,000J
Packaged
60mm

Suppression

Peak Current:
Peak Energy:
Mount/Form Factor:
Disc Size:

V

130-625 VAC
170-825 VDC
1,750-10,000A
50-273J
Radial Leaded
7, 10, 14, 20mm
N/A

®

Operating Voltage:

D

115-420 VAC
170-420 VDC
6,000-10,000A
50-320
Radial Leaded
14, 20mm
iTMOV Varistor Only

®

Operating Voltage:

®

®

®

C-III Series

Contact factory for additional information.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

173

Suppression Products

Overvoltage Suppression Products
Surge Suppression Fuses

Features
• Very current-limiting under AC short-circuit conditions.
• Available in multiple mounting configurations (cartridge, bolt-in, PC
board mount).
• Provides short-circuit protection in TVSS systems and complements
the Littelfuse line of overvoltage products (HA, HB34, TMOV TM and
iTMOV TM varistors as well as the AK-10 series TVS diodes).

Applications
• TVSS products
• Surge arrestors

The Littelfuse Varistor Protection ( LVSP) Fuses are intended for the
protection of TVSS products. The LVSP series has been designed to
survive the 8x20µs lightning surges described in various standards
(UL1449, IEC61000-4-5 & IEEE C62.41) without opening. This allows
the TVSS to perform the necessary suppression. The LVSP is not
rated for continuous current and the ratings are specific 8x20µs surge
capability. The LVSP series can be used to facilitate TVSS module
compliance to UL 1449 in permanently connected applications
(abnormal overvoltage, unlimited current conditions).

Catalog No.

8x20µs
Surge Rating

LVSP 5
LVSP 10
LVSP 15
LVSP 20
LVSP 30
LVSP 40
LVSP 60
LVSP 80
LVSP 100

5,000
10,000
15,000
20,000
30,000
40,000
60,000
80,000
100,000

Nominal
Melting I2 t
(A 2s)

Nominal
Clearing I2 t
(A 2s)

359
1,300
3,267
4,940
11,950
20,550
39,240
75,000

981
3,210
6,235
11,710
35,325
61,700
145,555
254,000
Contact Factory

Ipeak@100kA
60Hz (A)
3,700
5,823
7,765
8,135
12,478
15,250
19,604
24,600

Specifications
Voltage Rating:
Interrupting Rating:
Ratings:
Approvals:

LVSP

600 VAC
200,000 amps
5 – 100kA 8x20µs surge withstand
UL Recognized under the components program.
(File No. E71611)

Recommended Fuse Blocks
PEAK LET-THRU IN AMPERES

L60030M and LPSM series – LVSP (5-20)-2
LJ60030 and LPSJ30 series – LVSP (30-80)-2

Mounting Options
Surge Rating

Suppression

5
10
15
20
30
40
60
80
100
AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

174

Cartridge
LVSP 5-2
LVSP 10-2
LVSP 15-2
LVSP 20-2
LVSP 30-2
LVSP 40-2
LVSP 60-2
LVSP 80-2
–

Catalog Number
Leaded
LVSP 5-R
LVSP 10-R
LVSP 15-R
LVSP 20-R
–
–
–
–
–

Bolt-In
–
–
–
–
LVSP 30
LVSP 40
LVSP 60
LVSP 80
LVSP 100-L

Note: Contact factory for dimensions and availability of specific mounting
configurations.

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Terms and Definitions

177-181

Electrical Safety Guide

182-183

Fuse Application Guide

184-203

Motor Protection Tables

204-206

Condensed Cross Reference

207

Alphanumeric Index

208

www.littelfuse.com

Fuseology

Fuseology
Introduction

Fuseology provides the information needed to choose the correct
types of Littelfuse POWR-GARD™ fuses for most applications.
Definition of Terms is followed by Overcurrent Protection
Fundamentals. If there are any questions or if additional data is
needed for a specific use, call the Littelfuse Technical Support and
Engineering Service Group at 1-800-TEC-FUSE (1-800-832-3873)
or visit us online at www.littelfuse.com/technicalcenter.

Call 1-800-TEC-FUSE for

Definitions

177–181

Electrical Safety

182-183

Overcurrent Protection Fundamentals
(Fuses and How They Work) Index

184

Why Overcurrent Protection

184

What is Quality Overcurrent Protection

184

Overcurrent Types and Effects

184

Fuse Characteristics (600 volts and below)

185

Time-Current Characteristics

186-187

Peak Let-through Charts

187-189

Fuse Ampere Ratings

189

Fuse Dimensions

189

Fuse Coordination (Developing a Selective System)

190-191

Component Short-circuit Protecting Ability

190

Technical Support and

UL/CSA Fuse Classes and Their Applications

192-193

Engineering Services or visit

Fuses for Specific Applications
(600 Volts and Below) Index

194

Protecting Service Entrance and Feeder Conductors

194

Main Services and Feeders

194

Motor Protection

194-198

Motor Overload Protection (running overcurrent)

195-197

Motor Feeder (100% Motor Load) Protection over 600A

197

Motor Branch Circuit Protection over 600A

197

Motor Controller (Starter) Protection over 600A

197

Control Transformer Protection

197-198

Primary Fusing With Secondary Fusing

198

Secondary Fusing of Transformers

198

Lighting Fixture Protection

198

Street Lighting & Other Weatherproof Overcurrent Protection

198

Cable Short-circuit Protection (Cable Limiter Application)

199

Semiconductor and Solid-state Device Protection

199

Effect of Ambient Temperature on Fuses

199

Medium Voltage Protection (2400 volts to 38.0 kV)

200-203

Motor Protection Tables

204-206

Fuseology

www.littelfuse.com/technicalcenter

176

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Definitions

Current

Definition of Terms Frequently Used
When Selecting Overcurrent Protection
AIC or A.I.C.
See Interrupting Capacity.

Peak Current which would occur
without current limitation

AIR or A.I.R.
See Interrupting Rating.

Ambient Temperature
The air temperature surrounding a device. For fuses or circuit breakers in
an enclosure, the air temperature within the enclosure.

Peak Let-through Current

Arcing
Current

Arcing Energy (l2t)
Melting Energy (l2t)

Ampacity
The current in amperes that a conductor can carry continuously under
the conditions of use without exceeding its temperature rating. It is
sometimes informally applied to switches or other devices. These are
more properly referred to by their ampere rating.

Time

Melting
Current
Melting
Time

Arcing
Time

Figure 1
Showing arcing and melting currents and arcing, melting and clearing times.

Ampere Rating
The current rating, in amperes, that is marked on fuses, circuit breakers,
or other equipment.

PEAK
INSTANTANEOUS ARC VOLTAGE
183% OF CYCLEPEAK

2

Ampere-Squared-Seconds (I t)

RESTORED VOLTAGE

A means of describing the thermal energy generated by current flow.
When a fuse is interrupting a current within its current-limiting range,
the term is usually expressed as melting, arcing, or total clearing I2t.
Melting I2t is the heat energy passed by a fuse after an overcurrent
occurs and until the fuse link melts. It equals the rms current squared
multiplied by melting time in seconds. For times less than 0.004
seconds, melting I2t approaches a constant value for a given fuse.
Arcing I2t is the heat energy passed by a fuse during its arcing time.
It is equal to the rms arcing current squared (see below), multiplied by
arcing time.
Clearing I2t (also Total Clearing I2t) is the ampere-squared seconds
(I2t) through an overcurrent device from the inception of the overcurrent
until the current is completely interrupted. Clearing I2t is the sum of the
Melting I2t and the Arcing I2t.

Arc-Flash
The suddent release of heat energy and intense light at the point of an
arc. Can be considered a short-circuit through the air, usually created by
accidental contact between live conductors.

Arcing Current (See Figure 1)
The current that flows through the fuse after the fuse link has melted
and until the circuit is interrupted.

Figure 2
Arcing Time (See Figure 1)
The time between the melting of a fuse link, or parting of circuit breaker
contacts, until the overcurrent is interrupted.

Arc Voltage (See Figure 2)
Arc voltage is a transient voltage that occurs across an overcurrent
protection device during the arcing time. It is usually expressed as peak
instantaneous voltage (Vpeak or Epeak), rarely as rms voltage.

Asymmetrical Current
See Symmetrical Current.

Available Short-Circuit Current
(also Available or Prospective Fault Current)

Arcing Fault

Blade Fuse

A short-circuit that arcs at the point of fault. The arc impedance
(resistance) tends to reduce the short-circuit current. Arcing faults may
turn into bolted faults by welding of the faulted components. Arcing
faults may be phase-to-phase or phase-to-ground.

See Knife Blade Fuse.

Arcing I2t

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

See Ampere-Squared-Seconds (I2t).

The maximum rms Symmetrical Current that would flow at a given
point in a system under bolted-fault conditions. Short-circuit current
is maximum during the first half-cycle after the fault occurs. See
definitions of Bolted Fault and Symmetrical Current.

Body
The part of a fuse enclosing the fuse elements and supporting the
contacts. Body is also referred to as cartridge, tube, or case.

www.littelfuse.com

177

Fuseology

Fuse Application Guide
Definitions
Bolted Fault
A short-circuit that has no electrical resistance at the point of the fault.
It results from a firm mechanical connection between two conductors,
or a conductor and ground. Bolted faults are characterized by a lack of
arcing. Examples of bolted faults are a heavy wrench lying across two
bare bus bars, or a crossed-phase condition due to incorrect wiring.

Cartridge Fuse
A fuse that contains a current-responsive element inside a tubular fuse
body with cylindrical ferrules (endcaps).

limiting,” a fuse must mate with a fuseblock or fuseholder that has either a
rejection feature or dimensions that will reject non-current-limiting fuses.

Current-limiting Range
For an individual overcurrent protective device, the current-limiting range
begins at the lowest value of rms symmetrical current at which the
device becomes current-limiting (the threshold current) and extends
to the maximum interrupting capacity of the device. See definitions of
Threshold Current and Interrupting Capacity.

Current Rating
Case Size (also Cartridge Size)

See Ampere Rating.

The maximum allowable ampere rating of a cartridge fuse having
defined dimensions and shape. For example, case sizes for UL Listed
Class H, K, J, RK1, and RK5 are 30, 60, 100, 200, 400, and 600
amperes. The physical dimensions vary with fuse class, voltage, and
ampere rating. UL Standards establish the dimensions for each UL Fuse
Class. This catalog’s product section contains case size dimensions for
all Littelfuse POWR-GARDTM fuses.

Dual-element Fuse
A fuse with internal construction consisting of a separate time-delay
overload element(s) that interrupts overcurrents up to approximately
500%-600% of its nominal rating, plus separate fuse links that quickly
open higher value currents. All dual-element fuses have time delay, but,
since there are other methods of achieving time delay, not all time-delay
fuses have dual-element construction. See Time-Delay Fuse.

Clearing I 2t
See Ampere-Square-Seconds (I2t).

Element

Clearing Time (see Figure 1)

A fuse’s internal current-carrying parts that melt and interrupt the
current when subjected to an overcurrent of sufficient duration or value.
Also called fuse link.

The time between the initiation of an overcurrent condition to the point
at which the overcurrent is interrupted. Clearing Time is the sum of
Melting Time and Arcing Time.

Contacts (Fuse)
The external metal parts of the fuse used to complete the circuit. These
consist of ferrules, caps, blades or terminals, as shown in this catalog.

Fast-Acting Fuse
May also be termed Normal-opening fuse.
A fuse that has no intentional, built-in, time delay. Actual opening time
is determined by the fuse class, the overcurrent, and other conditions.
Fast-acting is indicated on the fuse label by “Fast-Acting”, “F-A”, “F”, or
other suitable marking.

Coordination or Coordinated System
Fault

See Selective Coordination.

Same as Short-Circuit and used interchangeably.

Continuous Load
An electrical load where the maximum current is expected to continue
for 3 hours or more.

Fault Current

Current-limiting Fuse (See Figure 3)

Filler

A fuse which, when interrupting currents within its current-limiting range,
reduces the current in the faulted circuit to a magnitude substantially less
than that obtainable in the same circuit if the device was replaced with a
solid conductor having comparable impedance. To be labeled “current-

A material, such as granular quartz, used to fill a section or sections of a
fuse and aid in arc quenching.

Fuse
An overcurrent protective device consisting of one or more currentcarrying elements enclosed in a body fitted with contacts, so that the
fuse may be readily inserted into or removed from an electrical circuit.
The elements are heated by the current passing through them, thus interrupting current flow by melting during specified overcurrent conditions.

Current which
would flow if
not interrupted

Current

Same as Short-Circuit current.

Ground Fault

Fuseology

Current before fault

A short-circuit caused by insulation breakdown between a phase
conductor and a grounded object or conductor.

Time

Fault occurs

Fuse opens and
clears short circuit
in less than ½ cycle Arc is extinguished

Figure 3
178

I 2t
See Ampere-Squared-Seconds (I2t).

IEC Type 2 Protection
Fused protection for control components that prevents damage to these

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Definitions
components under short-circuit conditions. A more complete discussion
of this subject is included in the Motor and Motor Circuit Protection
Section. See definition of No Damage.

No Damage
A term describing the requirement that a system component be in
essentially the same condition after the occurrence of a short-circuit as
prior to the short-circuit.

Instantaneous Peak Current (Ip or Ipeak)
The maximum instantaneous current value developed during the first
half-cycle (180 electrical degrees) after fault inception. The peak current
determines magnetic stress within the circuit. See Symmetrical Current.

Non-renewable Fuse

Interrupting Capacity (AIC)

Normal-opening Fuse

The highest available symmetrical rms alternating current (for DC fuses
the highest direct current) at which the protective device has been tested,
and which it has interrupted safely under standardized test conditions. The
device must interrupt all available overcurrents up to its interrupting capacity.
Also commonly called interrupting rating. See Interrupting Rating below.

See Fast-Acting Fuse.

Interrupting Rating (IR, I.R., AIR or A.I.R.)
The highest RMS symmetrical current, at specified test conditions, which
the device is rated to interrupt. The difference between interrupting capacity
and interrupting rating is in the test circuits used to establish the ratings.

A fuse that must be replaced after it has opened due to an overcurrent.
It cannot be restored to service.

One-time Fuse
Technically, any non-renewable fuse. However, the term usually refers
to UL Class H fuses and to fast acting Class K5 fuses. Such fuses are
not current-limiting and do not have a rejection feature. One-time fuses
are also referred to as “Code” fuses.

Overcurrent
Any current larger than the equipment, conductor, or devices are rated
to carry under specified conditions.

Inverse-time Characteristics
A term describing protective devices whose opening time decreases
with increasing current.

IR or I.R. (also AIR or A.I.R.)

Overload
An overcurrent that is confined to the normal current path (e.g., not
a short-circuit), which if allowed to persist, will cause damage to
equipment and/or wiring.

See Interrupting Rating above.
Additional information regarding fuse applications for overload protection
can be found later in this Fuseology section.

Kiloamperes (kA)
1,000 amperes.

Peak Let-through Current (See Figure 4)
Cylindrical or square body fuses with flat blade terminals extending from the
fuse body. Knife blades may be designed for insertion into mating fuse clips,
and/or to be bolted in place. Knife blade terminals may include a rejection
feature that mates with a similar feature on a fuse block of the same class.

Melting Current (see Figure 1)
The current that flows through the fuse from the initiation of an
overcurrent condition to the instant arcing begins inside the fuse.

Melting I2t
See Ampere-Squared-Seconds (I2t).

Melting Time (see Figure 1)
The time span from the initiation of an overcurrent condition to the
instant arcing begins inside the fuse.

The maximum instantaneous current that passes through an overcurrent
protective device during its total clearing time when the available current
is within its current-limiting range.

Power Factor (X/R)
As used in overcurrent protection, power factor is the relationship
between the inductive reactance (X) and the resistance (R) in the
system during a fault. Under normal conditions a system may be
operating at a 0.85 power factor (85%). When a fault occurs, much of
the system resistance is shorted out and the power factor may drop to
25% or less. This may cause the current to become asymmetrical. See
definition of Symmetrical Current. The UL test circuits used to test fuses

Current

Knife Blade Fuse

Peak Current which would occur
without current limitation

NEC
In general, the National Electrical Code® (NEC®). Specifically, as
referenced herein, NEC refers to NFPA Standard 70, National Electrical
Code®, National Fire Protection Association, Quincy, MA 02269.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Peak Let-through Current

Fuseology

Sections of the NEC reprinted herein, and/or quotations therefrom, are
done so with permission. The quoted and reprinted sections are not
the official position of the National Fire Protection Association, which is
represented only by the Standard in its entirety. Readers are cautioned
that not all authorities have adopted the most recent edition of the NEC;
many are still using earlier editions.

Time
Figure 4
179

Fuseology

Fuse Application Guide
Definitions
CURRENT FLOW

In a "normal" circuit,
current is determined by
load IMPEDANCE

LOAD

with interrupting ratings exceeding 10,000 amperes are required to have
a power factor of 20% or less. Since the power factor of test circuits
tends to vary during test procedures, actual test circuits are usually set
to a 15% power factor. The resulting asymmetrical current has an rms
value of 1.33 times the available symmetrical rms. The instantaneous
peak current of the first peak after the fault is 2.309 times the available
symmetrical rms.

GEN.

Prospective Current

Rating
A designated limit of operating characteristics based on definite
conditions such as current rating, voltage rating and interrupting rating.

(Heavy lines indicate
increased current)

GEN.

Accidental
connection
creates fault

LOAD

See Available Short-Circuit Current.

Rectifier Fuse
See Semiconductor Fuse.
In a short-circuit, current is limited
only by impedance of fault path.
Current may increase to many times
load current.

Rejection Feature
The physical characteristics of a fuse block or fuseholder that prevents
the insertion of a fuse unless it has mating characteristics. This may
be done through the use of slots, grooves, projections, or the actual
physical dimensions of the fuse. This feature prevents the substitution
of fuses of a Class or size other than the Class and size intended.

Renewable Element (also Renewable Link)
A renewable fuse current-carrying part that is replaced to restore the
fuse to a functional condition after the link opens due to an overcurrent
condition.

Renewable Fuse
A fuse that may be readily restored to service by replacing the
renewable element after operation.

Figure 6
service, which simplifies the identification and location of overloaded
equipment or short-circuits. For additional information, refer to the Fuse
Coordination pages of this Fuseology section.

Semiconductor Fuse
A fuse specifically designed to protect semiconductors such as silicon
rectifiers, silicon-controlled rectifiers, thyristers, transistors, and similar
components. For additional information, refer to the Semiconductor
Section of this catalog.

Short-Circuit (See Figure 6)
Selective Coordination (See Figure 5)
In a selectively coordinated system, only the protective device
immediately on the line side of an overcurrent opens. Upstream
protective devices remain closed. All other equipment remains in

A current flowing outside its normal path. It is caused by a breakdown of
insulation or by faulty equipment connections. In a short-circuit, current
bypasses the normal load. Current is determined by the system impedance
(AC resistance) rather than the load impedance. Short-circuit currents may
vary from fractions of an ampere to 200,000 amperes or more.

Short-Circuit Rating
The maximum RMS symmetrical short-circuit current at which a given
piece of equipment has been tested under specified conditions, and
which, at the end of the test is in essentially the same condition as prior
to the test. Short-circuit ratings (also called withstand ratings) apply to
equipment that will be subjected to fault currents, but which are not
required to interrupt them. This includes switches, busway (bus duct),
switchgear and switchboard structures, motor control centers and
transformers.

A

B

C

D

E

In a selective system:
For a fault at "X" only fuse "C" will open.
For a fault at "Y" only fuse "F" will open.

X

Fuseology

F

G

H

J

Y

Figure 5
180

Most short-circuit ratings are based on tests which last three complete
electrical cycles (0.05 seconds). However, if the equipment is protected
during the test by fuses, or by a circuit breaker with instantaneous trips,
the test duration is the time required for the overcurrent protective
device to open the circuit.
When so protected during testing, the equipment instructions and labels
must indicate that the equipment shall be protected by a given fuse
class and rating or by a specific make, type, and rating of circuit breaker.

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Definitions
Zero Axis

B

Figure 7
Symmetrical Current

Zero Axis
Unequal
Peaks

Peak Let-Through in Amperes

Equal
Peaks

Peak let-through current

Fuse approximate
threshold current = 4000A

4000

Figure 8
Asymmetrical Current

A

1000

Circuit breakers equipped with short-delay trip elements instead of
instantaneous trip elements have withstand (short-circuit) ratings
in addition to their interrupting rating. The breaker must be able to
withstand the available fault current during the time that opening is
delayed.

Available Fault Current Symmetrical RMS Amperes

Symmetrical Current

Figure 9

The terms “Symmetrical Current” and “Asymmetrical Current” describe
an AC wave symmetry around the zero axis. The current is symmetrical
when the peak currents above and below the zero axis are equal in
value, as shown in Figure 7. If the peak currents are not equal, as
shown in Figure 8, the current is asymmetrical.
The degree of asymmetry during a fault is determined by the change
in power factor (X/R) and the point in the voltage wave when the fault
occurs. See definition of Power Factor. In general, lower short-circuit
power factors increase the degree of asymmetry.

Threshold Current
The minimum current for a given fuse size and type at which the
fuse becomes current-limiting. It is the lowest value of available rms
symmetrical current that will cause the device to begin opening within
the first 1 / 4 cycle (90 electrical degrees) and completely clear the circuit
within 1 / 2 cycle (180 electrical degrees). The approximate threshold
current can be determined from the fuse’s peak let-through charts.

overload range (200%-600% of the fuse rating) permits the fuse to
withstand system switching surges, motor starting currents, and other
harmless temporary overcurrents.
UL Standards require time-delay Class H, K, RK1, RK5, and J fuses to
hold 500% of their normal current rating for a minimum of 10 seconds.
They must also pass the same opening time tests (135% and 200% of
current rating) as fast acting fuses.
Time-delay Class CC, CD, G, Plug, and Miscellaneous fuses have
different requirements. See the corresponding descriptions given in the
Product Information Section.

See Figure 9.

For the UL Standard, Class L fuses have no standard time-delay. The
time-delay varies from type to type for a given manufacturer, as well
as from manufacturer to manufacturer. For reference, Littelfuse KLPC
series POWR-PRO® fuses do hold 500% of rated current for a minimum
of ten seconds.

Threshold Ratio

Voltage Rating

The threshold current divided by the ampere rating of a specific type or
class overcurrent device. A fuse with a threshold ratio of 15 becomes
current-limiting at 15 times its current rating.

The maximum rms AC voltage and/or the maximum DC voltage at
which the fuse is designed to operate. For example, fuses rated 600
volts and below may be applied at any voltage less than their rating.
There is no rule for applying AC fuses in DC circuits such as applying the
fuse at half its AC voltage rating. Fuses used on DC circuits must

Time-Delay Fuse

© 2005 Littelfuse • POWR-GARD™ Products Catalog

have DC ratings.

Fuseology

Fuses that have an intentional, built-in delay in opening. When compared
to fast-opening fuses, time-delay fuses have an increased opening
time for overcurrents between approximately 200% and 600% of
the fuse’s current rating. Time-delay is indicated on the fuse label by
“Time-Delay”, “T-D”, “D”, or other suitable marking. Time-delay in the

Withstand Rating
See Short-Circuit.

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181

Fuseology

Electrical Safety Guide

Electrical safety is an important issue for employers and employees
alike. Unfortunately there are still about 30,000 electrical accidents
occurring each year, each of them potentially costing up to $15 million,
and the number is increasing.

OSHA requires all employers to perform a hazard assessment of their
facilities and train their employees to become qualified to perform a
specific task. Being aware, following safety regulations, codes and
standards, and using protective devices will minimize hazards and help
establish safer work practices.

FACTS
•

There are approximately 30,000 electrical shock accidents every year.

•

Over 3600 disabling electrical contact injuries occur annually.

•

Over 2000 workers are sent to burn centers each year with severe Arc-Flash burns.

•

Over 1000 electrical workers die each year from workplace accidents.

•

60% of workplace accident deaths are caused by burn injuries.

•

Electrocutions are the 4th leading cause of traumatic occupational fatalities.

•

Estimates show that 10 Arc-Flash incidents occur every day in the U.S.

•

97% of all electricians have been shocked or injured on the job.

•

Medical costs per person can exceed $4 million for severe electrical burns.

•

Total costs per electrical incident can exceed $15 million.

•

In the year 2002, work injuries cost Americans $146.6 billion.

OSHA Standard 29 CFR Part 1910 Subpart S (electrical)
generally addresses safety standards, work practices, and maintenance
requirements.

Implementing and following a well designed Electrical Safety
Program will protect employees and employers against:
• Injury to personnel

NFPA 70E Standard for Electrical Safety in the Workplace
concentrates on safety requirements to protect employees. OSHA
commonly is referred to as the “Shall” and NFPA 70E as the “How”
with regards to electrical safety.

• Increased insurance and workman compensation

Both OSHA and NFPA 70E reinforce the need for Electrical
Hazard Analysis.

• Unplanned equipment repair or replacement

The analysis should address all potential electrical hazards including
shock, Arc-Flash, Arc-Blast, and burns. NFPA 70E Article 110.8(B)(1)
specifically requires Electrical Hazard Analysis within all areas of the
electrical system that operate at 50 volts or greater. The results of the
Electrical Hazard Analysis will determine the work practices, protection
boundaries, personal protective equipment to be used, and other
procedures to protect employees from an Arc-Flash or contact with live
conductors.

• OSHA citations and fines

• Lost or unusable materials

• Multi-million dollar lawsuits
• Possible bankruptcy

Fuseology

Electrical Safety is not an option; it is absolutely necessary for
both workers and employers.

182

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Fuseology

Electrical Safety Guide

The following is a brief overview of requirements for working on electrical equipment.
NOTE: Only the complete standards constitute the law or regulation and all parts must be followed where applicable.

!

!

It should control and re-engineer the processes in the
workplace to insure Electrical Safety including: hazard
assessments, labeling of equipment, training programs,
energized work permits and using current-limiting devices to
minimize hazards. Refer to NFPA 70E Article 110.7 for more
information on establishing an Electrical Safety Program.
Develop formal training for equipment operators, service
technicians and any other employees that might come in
contact with the identified hazard. “Qualify” them for hazard
preparations and contingencies (preparations prior to servicing
electrical systems or coming within boundaries of electrical
hazards). For more information refer to OSHA 1910.332 and
NFPA 70E Article 110.6.

Understand and follow NFPA and OSHA
guidelines
Allow only “Qualified” individuals to perform work. Qualified
workers must be knowledgeable on the equipment and the
hazards that exist and receive documented training. For more
information refer to OSHA 1910.332 and NFPA 70E Article
110.6(D)(1).
Establish a “Safe Work Condition” and work on system
components de-energized whenever possible. Consult NFPA
70E Article 120.1 for establishing an Electrically Safe Work
Condition.

!

!

Communicate the hazards to employees
Train your employees.
Label equipment and service entrances of the “Hazards
Assessed.” Refer to NEC Article 110.16 for Warning Label
Requirements.

Develop an Electrical Safety Program
Determine available fault currents and hazard risks at points
where there is the potential for contact with an energized
part. In many cases, this requires a complete Hazard Risk
Assessment. As a result, the entire electrical system is
analyzed and the one-line diagram for the facility is reviewed
and updated. The outcome is used to determine the Hazard
Risk Category (0 to 4), required level of PPE, Protection
Boundaries and equipment that requires warning labels. Refer
to OSHA 1910.132(d) and NFPA 70E Article 110.8(B)(1) for
more information on Electrical Hazard Analysis.

Establish an Electrical Safety Program.

Create a safety culture and support safety processes and
awareness such as: Deenergize and Verify, “Test Before
Touch”, Lockout / Tagout, the proper use of PPE and insulated
tools, providing barriers to warn and restrict access to
unqualified personnel, etc.

!

Select the safest circuit protection
devices to minimize electrical hazards

32 inches

35 kA

1

480 VAC

2.77

42 inches

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

12 inches

1 inch

Fuseology

Bus: SERVICE4

cal/cm2

05/12/05

183

Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
Overcurrent Protection Fundamentals (Fuses and How They Work)

Introduction
An important part of developing quality overcurrent protection is an
understanding of system needs and overcurrent protective device
fundamentals. This section discusses these topics with special attention
to the application of fuses. If you have additional questions, call our
Technical Support and Engineering Services Group at 1-800-TEC-FUSE
(1-800-832-3873). Definitions of terms used in this section are located
in the preceding section.

INDEX
Page
Why Overcurrent Protection? ..................................................184
What is Quality Overcurrent Protection? .............................184
Overcurrents, Types and Effects .............................................184
Overloads ..............................................................................184
Short-Circuits ......................................................................185
Fuse Characteristics (600 volts and below) .............................185
Voltage Rating.....................................................................185
Interrupting Rating ............................................................185-186
300,000 AIC Fuses........................................................186

Time Current Characteristics ...................................................186
Overloads ..............................................................................186
Fast-Acting Fuses ..........................................................186
Time-Delay (Dual-Element) Fuses ...............................186
Very Fast-Acting Fuses .................................................187
Short Circuits.......................................................................187
Current-Limiting Fuses ..................................................187
Fast-Acting Fuses ..........................................................187
Dual-Element (Time-Delay) Fuses ...............................187
Very Fast-Acting Fuses .................................................187
Time-current Curves .........................................................187
Peak Let-through Charts............................................................187

standards for overcurrent devices and testing procedures that show
compliance with the standards and with the NEC. These organizations
include: the American National Standards Institute (ANSI), National
Electrical Manufacturers Association (NEMA), and the National Fire
Protection Association (NFPA) working with Nationally Recognized
Testing Laboratories (NRTL) such as Underwriters Laboratories (UL).
Electrical systems must meet applicable code requirements including
those for overcurrent protection before electric utilities can provide
electric power to a facility.

What is Quality Overcurrent Protection?
A system with quality overcurrent protection has the following
characteristics:
1. Meets all legal requirements, such as NEC, OSHA, local codes, etc.
2. Provides maximum safety for personnel, exceeding minimum code
requirements as necessary.
3. Minimizes overcurrent damage to property, equipment, and electrical
systems.
4. Provides coordinated protection. Only the protective device
immediately on the line side of an overcurrent opens to protect the
system.
5. Is cost effective. Provides reserve interrupting capacity for
future growth. Not subject to obsolescence. Requires minimum
maintenance that can be done by regular maintenance personnel
using readily available tools and equipment.

Overcurrent Types and Effects
An overcurrent is any current that exceeds the ampere rating of
conductors, equipment, or devices under conditions of use. The term
“overcurrent” includes both overloads and short-circuits.

Using the Peak Let-through Charts
(“up-over-and-down”) ............................................................188-189

Fuse Ampere (current) Ratings ...............................................189
Fuse Dimensions .........................................................................189
Fuse Coordination, Selective Systems .................................190-191
Component Short-circuit Protecting Ability .......................190
UL/CSA Fuse Classes and Their Applications ....................192-193
Why Overcurrent Protection?
All electrical systems eventually experience overcurrents. Unless
removed in time, even moderate overcurrents quickly overheat system
components, damaging insulation, conductors, and equipment. Large
overcurrents may melt conductors and vaporize insulation. Very high
currents produce magnetic forces that bend and twist bus bars. They
can pull cables from their terminals and crack insulators and spacers.

Fuseology

Too frequently, fires, explosions, poisonous fumes and panic accompany
uncontrolled overcurrents. They not only damage electrical systems and
equipment, but may cause injury or death to personnel.

184

Overloads
An overload is an overcurrent that is confined to normal current paths.
There is no insulation breakdown.

Sustained overloads are commonly caused by installing excessive
equipment such as additional lighting fixtures. They are also caused by
overloading mechanical equipment and by equipment breakdown such
as failed bearings. If not disconnected within established time limits,
sustained overloads eventually overheat circuit components causing
thermal damage to insulation and other system components.
Overcurrent protective devices must disconnect circuits and equipment
experiencing continuous or sustained overloads before overheating
occurs. Even moderate insulation overheating seriously reduces its life.
For example, motors overloaded by only 15% may have less than 50%
insulation life.

To reduce these hazards, the National Electrical Code® (NEC®), OSHA
regulations, and other applicable design and installation standards require
overcurrent protection that will disconnect overloaded or faulted equipment.

Temporary overloads occur frequently. They may be caused by
temporary equipment overloads such as a machine tool taking too deep
of a cut, or may result from starting inductive loads, such as motors.
Since temporary overloads are, by definition, harmless, overcurrent
protective devices should not open the circuit.

Industry and governmental organizations have developed performance

Fuses selected must have sufficient time-delay to allow motors to start

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
and temporary overloads to subside. However, should the overcurrent
continue, fuses must open before system components are damaged.
Littelfuse POWR-PRO® and POWR-GARDTM time-delay fuses are
designed to meet these needs. They hold 500% current for a minimum
of ten seconds, yet open quickly on higher values of current. Even
though government mandated high efficiency motors and NEMA
design E motors have much higher locked rotor currents, POWR-PRO
time-delay fuses such as the FLSR_ID, LLSRK_ID, or IDSR series
have sufficient time-delay to permit motors to start when the fuses are
properly selected in accordance with the NEC.

Short-Circuits
Types of Short-Circuits
Short-circuits are divided into bolted faults, arcing faults
and ground faults. Each are defined in the Definition section.
Causes of Short-Circuits
A short-circuit is current flowing outside of its normal path. It is caused
by an insulation breakdown or faulty connection. During a circuit’s
normal operation, the connected load determines current. During a
short-circuit, the current bypasses load and the current takes a “shorter
path,” hence: short-circuit. Since there is no load impedance, only the
total distribution system’s impedance from the utility’s generators to
the fault will limit current flow. See Figure 6.
Many electrical systems have single-phase impedance of 0.005 ohms
or less. Applying Ohm’s Law (I = E/Z for AC systems), a 480 volt singlephase circuit with a ten ohm load impedance would draw 48 amperes
(480/10 = 48). If, when the load is shorted, the same circuit has a 0.005
ohm system impedance, the available fault current would be 96,000
amperes (480/0.005 = 96,000). Short-circuits are currents out of their
normal path and regardless of their value, they must be removed
quickly.
Effects of Short-Circuit Currents
If not removed quickly, the large currents associated with short-circuits
may have three profound effects on an electrical system: heating,
magnetic stress, and arcing.

Heating. Current passing through an electrical system heats every
part of it. When overcurrents are large enough, heating is practically
instantaneous. The energy in such overcurrents is measured in amperesquared seconds (I2t). An overcurrent of 10,000 amperes that lasts for
0.01 seconds has an I2t of 1,000,000. If the current could be reduced
to 1,000 amperes for the same period of time, I2t would be reduced
to 10,000 — only one percent of the original value. If the current in a
conductor increases 10 times, the I2t increases 100 times. A current
of only 7,500 amperes can melt a #8 AWG copper wire in 0.1 second.
Within eight milliseconds (0.008 seconds or one-half cycle), a current
of 6,500 amperes can raise the temperature of #12 AWG THHN
thermoplastic insulated copper wire from its operating temperature of
75°C to its maximum short-circuit temperature of 150°C.

Magnetic stress. Magnetic stress (or force) is a function of the peak

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Arcing. Arcing at the point of fault melts and vaporizes the conductors
and components involved in the fault. The arcs often burn through
raceways and equipment enclosures showering the area with molten
metal that quickly starts fires and/or injures personnel in the area.
Additional short-circuits are often created when vaporized material is
deposited on insulators and other surfaces. Sustained arcing-faults
vaporize organic insulation. These vapors may explode or burn.
Fuse characteristics (600 volts and below)
Since overcurrent protection is crucial to reliable electrical system
operation and safety, overcurrent device selection and application should
be carefully considered. When selecting fuses, the following parameters
need to be evaluated:

Voltage Rating
Fuse voltage ratings must equal or exceed the circuit voltage where the
fuses will be installed, and fuses used in DC circuits must be rated for DC.
Exceeding the voltage ratings or using an AC only fuse in a DC circuit could
result in violent destruction of the fuse. Standard 600 volt and below fuses
may be applied at any voltage less than their rating. For example, a 600
volt fuse may be used in a 277 volt or even a 32 volt system.

NOTE: This does not apply to semiconductor fuses and medium
voltage fuses. See the semiconductor and medium voltage fuse
application data later in this section for voltage limitations of these fuses.
UL Listed low-voltage power fuses are available with AC voltage ratings
of 125, 250, 300, 480, and 600 volts, and DC voltage ratings of 60, 125,
160, 250, 300, 400, 500, and 600 volts. Fuses may be rated for AC
only or DC only, or they may have both an AC and a DC voltage rating.
Supplementary fuses have voltage ratings from 32 to 1,000 volts AC
and/or DC.
300 volt Class T fuses (Littelfuse JLLN series) may only be used for
single-phase to neutral loads where the voltage does not exceed 300
volts to ground. They may not be used in three-phase, four wire, 480/277
volt, wye systems or in 480 volt corner-grounded delta systems.

Interrupting Rating
A fuse’s interrupting rating is the highest available symmetrical rms
alternating current that the fuse is required to safely interrupt at rated
voltage under standardized test conditions without being damaged. A
fuse must interrupt all overcurrents up to its interrupting rating. Fuses
are available with interrupting ratings of 10,000A, 50,000A, 100,000A,
200,000A, and 300,000A.
NEC Article 110.9 requires all equipment intended to break current at
fault levels to have an interrupting rating sufficient for system voltage
and current available at the equipment’s line terminals. Refer to Figure
10. Select fuses with interrupting ratings which equal or exceed the available fault current.

Fuseology

Currents larger than this may immediately vaporize organic insulations.
Arcs at the point of fault or from mechanical switching such as
automatic transfer switches or circuit breakers may ignite the vapors
causing violent explosions and electrical flash.

current squared. Fault currents of 100,000 amperes can exert forces
of more than 7,000 lb. per foot of bus bar. These stresses may injure
insulation, pull conductors from terminals, and stress equipment
terminals sufficiently to cause damage.

Standardizing on fuses with at least a 200,000 ampere interrupting
capacity (AIR) ensures that all fuses have an adequate interrupting

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185

Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
Overloads
Main Switchboard

While fuses must disconnect overloaded conductors and equipment
before the conductors and components are seriously overheated,
they should not disconnect harmless temporary overloads. To provide
overload protection for system conductors, UL has established
maximum fuse opening times at 135% and 200% of a fuse’s current
rating. All UL Listed fuses for application in accordance with the National
Electrical Code® (NEC®) must meet these limits whether they are fastacting or time-delay fuses.

Available fault
Current = 125,000A

Fast-Acting (Normal-Opening) Fuses
Available fault
Current = 85,000A

All fuses in main switchboard
must have an A.I.R. of at least
125,000A. Next higher standard
rating is 200,000A.
Fuses in panel must have at
least an 85,000 A.I.C. Next higher
standard rating is 100,000A., but
best choice is time-delay fuses
with 200,000 A.I.R.

Figure 10
rating, and provides reserve interrupting capacity for future increases in
available fault current.

300,000 AIC Fuses
Littelfuse POWR-PRO® fuse series have a Littelfuse Self-Certified
interrupting rating of 300,000 amperes rms symmetrical. The 300,000
ampere testing was performed in a Nationally Recognized Testing Laboratory, and the tests were UL witnessed. UL has ruled that fuses with
a UL interrupting rating greater than 200,000 amperes must be marked
as “Special Purpose Fuses” and may not be labeled as UL Listed Class
RK5, RK1, L, etc.

Fuseology

Littelfuse feels that the “Special Purpose Fuse” classification adds
confusion to specification writing for both fuses and switches and
complicates fuse procurement. Since only a very small number of
installations have a real need for fuses with interrupting ratings in excess
of 200,000 amperes, Littelfuse will continue to UL List their fuses by
UL standard fuse classes that have interrupting ratings up to 200,000
amperes. Littelfuse fuses which have passed the 300,000 ampere tests
are marked on the label: “300kA (Self certified by Littelfuse)”. UL listing
cards showing 300,000 AIC and the special purpose classification are
available on request. Refer to the product section of this catalog for
information on specific fuse classes.

186

Fastoacting fuses (sometimes called “Normal-opening fuses”) have no
intentional time-delay. Typical opening times at 500% of the fuse ampere
rating range from 0.05 to approximately 2 seconds. Fast-Acting fuses
are suitable for non-inductive loads, such as incandescent lighting and
general-purpose feeders, or branch circuits with little or no motor load.
When protecting motors and other inductive loads, fast-acting fuses
must be rated at 200-300% of load currents to prevent nuisance opening
on in-rush currents. Fuses with such increased ratings no longer furnish
adequate protection from overloads. They provide only short-circuit protection. Overload relays or other overload protection must be provided to
protect conductors and equipment from overload conditions.

Time-Delay (Dual Element) Fuses
UL Classes CC, CD, G, H, L, RK5 and RK1 fuses, plus some of the
UL Listed Miscellaneous fuses, may have time-delay. If so, they are
identified on the fuse label with “Time-Delay”, “T-D”, “D”, or some
other suitable marking. Minimum time-delay varies with the fuse class,
and to some degree with the fuse ampere rating. UL standards for
POWR-GARDTM Fuses Products series IDSR, FLNR_ID, and FLSR_ID
(UL Class RK5), LLNRK, LLSRK, LLSRK_ID (UL Class RK1), and JTD,
JTD_ID (UL Class J) fuses require them to carry 500% rated current for
a minimum of 10 seconds. Standards for CCMR and KLDR (UL Class
CC and CD) and SLC (UL Class G) require them to carry 200% rated
current for a minimum of 12 seconds.
Although there is no UL Classification for time-delay Class L fuses, they
may be marked “Time-Delay.” The amount of time-delay is determined
by the manufacturer. POWR-PRO® KLPC series and POWR-GARD
KLLU series fuses will hold 500% current for 10 seconds or more.

Time Current Characteristics

In addition to providing time-delay for surges and short time overloads,
time-delay fuses meet all UL requirements for sustained overload
protection. On higher values of current, time-delay fuses are currentlimiting meaning they remove large overcurrents in less than one-half
cycle (0.008 seconds). Time-delay fuses provide the best overall
protection for both motor and general purpose circuits, and eliminate
nuisance fuse opening and most downtime.

Time current characteristics determine how fast a fuse responds to
overcurrents. All fuses have inverse time characteristics; that is, the fuse
opening time decreases as the value of overcurrent increases. When
properly rated in accordance with NEC requirements, fuses provide
both overload and short-circuit protection to system conductors and
components. However, in some instances such as when fuses are used
to backup circuit breakers or to provide motor branch circuit short-circuit
and ground fault protection, fuses provide only short-circuit protection.
A fuse’s response to overcurrents is divided into overloads and shortcircuits.

Compared to fast-acting fuses, time-delay fuses can be selected with
ratings much closer to a circuit’s operating current. For example, on
most motor circuits, RK5 and RK1 fuses can be rated at 125-150% of
a motor’s full load current (FLA). This provides superior overload and
short-circuit protection, and often permits using smaller, less expensive
switches. Time-delay fuses have gradually replaced most one-time and
renewable fuses. Today, more than 50% of all fuses sold by electrical
distributors are time-delay fuses such as Littelfuse POWR-PRO LLSRK_ID
series fuses.

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Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
Very Fast-Acting Fuses
Peak Let-through Charts

1000
800
600
400
300
200
100
80
60
40
30
20

TIME IN SECONDS

Current-limiting Fuses
Current-limiting fuses must have the following characteristics:
1. Limit peak currents to values less than those which would occur
if the fuses were replaced with solid conductors of the same
impedance. This reduced peak current is referred to as a fuse’s “Peak
Let-through Current.”
2. When the fault current exceeds the fuse threshold current, the fuse
must open the circuit in less than 180 electrical degrees (1/ 2 cycle)
after the start of the fault.
3. Matching fuse holders and/or fuse blocks must reject non-currentlimiting fuses and accept only current-limiting fuses of the stated
UL Class.

400A
600A

A fuse’s short-circuit response is its opening time on higher-value
currents. For power fuses, that is generally over 500 – 600% of
the fuse’s rating. As stated earlier, all fuses have inverse time
characteristics: the higher the current, the faster the opening time. Since
short-circuits should be removed quickly, inverse time is especially
important for short-circuit protection.

200A

15A

Short-Circuits

60A
100A

Fuses that are current-limiting open severe short-circuits within the
first half-cycle (180 electrical degrees) after the fault occurs. They also
reduce the peak current of the available fault current to a value less than
would occur without the fuse. This is shown in Figure 13.

30A

The principle use of very fast acting fuses is to protect solid-state
electronic components, such as semiconductors. Their special
characteristics, including quick overload response, very low I2t, Ipeak
and peak transient voltages provide protection for components that
cannot withstand line surges, low value overloads, or short-circuit
currents.

10
8
6
4
3
2
1
.8
.6
.4
.3
.2
.1
.08
.06
.04
.03
.02

20000
30000
40000
60000
80000
100000

2000
3000
4000
6000
8000
10000

200
300
400
600
800
1000

Fast-Acting (Normal Opening) Fuses

20
30
40
60
80
100

10

.01

CURRENT IN AMPERES

All fast-acting fuses provide fast short-circuit response within their
interrupting rating. Some are current-limiting, such as Class T and J.
Others are non-current-limiting, such as Class H.

Figure 11

Dual Element (Time-delay) Fuses
Littelfuse time-delay IDSR, FLNR_ID/FLSR_ID Class RK5, and LLNRK/
LLSRK_ID Class RK1 series fuses have true dual-element construction.
Time-delay elements are used for overload protection, and separate fast
acting fuse links are used to provide current-limiting short-circuit protection.

1000
800
600
400
300
200
100
80
60
40
30
20

Very Fast-Acting Fuses
Very fast-acting fuses are designed for very fast response to overloads
and short-circuits. They are very current-limiting.

1
.8
.6
.4
.3
.2

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CURRENT IN AMPERES

20000
30000
40000
60000
80000
100000

2000
3000
4000
6000
8000
10000

200
300
400
600
800
1000

.01

ratings of three fuse types: Littelfuse POWR-GARD dual-element, timedelay LLSRK series RK1 fuses; Littelfuse normal opening NLS series
fuses and Littelfuse very fast acting L60S series semiconductor fuses.
Table 1 compares the opening times for these fuses.
© 2005 Littelfuse • POWR-GARD™ Products Catalog

GREEN = TIME-DELAY FUSE
RED = NORMAL OPENING FUSE
BLUE = VERY-FAST ACTING FUSE

.1
.08
.06
.04
.03
.02

Fuseology

Figure 12 compares the average melting times for 100 and 600 amp

100 AMP

20
30
40
60
80
100

Time-current curves for Littelfuse POWR-GARD™ fuses are shown in
each product section. They show the average melting times for that
fuse series at any current. In order to make the curves more readable,
they are presented on log-log paper. The overcurrent values appear
at the bottom, and increase from left to right. Average melting times
appear on the left-hand side of the curve and increase from bottom to
top. The amperage ratings of the individual fuses for a given series are
listed at the top and increase from left to right. Figure 11 shows the
average melting time curves for a typical time-delay fuse series.

10

Understanding Time-current Curves

TIME IN SECONDS

600 AMP

10
8
6
4
3
2

Figure 12
187

Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals

Peak Current which would occur
without current limitation

A fuse current-limiting effects are shown graphically on Peak Letthrough charts such as the one in Figure 14. The values across the
chart’s bottom represent the available (also referred to as potential or
prospective) rms symmetrical fault current. The values on the chart’s
left side represent the instantaneous available peak current
and the peak let-through current for various fuse ratings.

Peak Let-through Current

Time
Figure 13
Current limiting effect of fuses

As an example, enter the chart on the bottom at 100,000 rms symmetrical amperes and read upwards to line A-B. From this point, read horizontally to the left and read an instantaneous peak current of 230,000
amperes. In a circuit with a 15% short-circuit power factor, the instantaneous peak of the available current approximates 2.3 times the rms
symmetrical value. Line A-B on the chart has a 2.3:1 slope.

100000
80000
60000
40000
30000
20000

Fuseology

The POWR-PRO® LLNRK 600 ampere RK1 current-limiting fuses
have reduced the 100,000 amperes available current to an apparent or
equivalent 18,000 amps. When protected by 600 amp LLNRK RK1 fuses,
equipment with short-circuit ratings of 22,000 amps may be safely con-

188

600
400
200
100
60
30

10000
8000
6000
4000
3000
2000
1000
800
600
400
300
200

A

200000

30000
40000
60000
80000
100000

100

AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

For example, with an available fault-current of 100,000 rms symmetrical
amperes, determine whether 600 amp 250 volt time-delay Class RK1
fuses can protect equipment with a 22,000 amp short-circuit rating.
Refer to Figure 15.
Locate 100,000A available fault-current on the bottom of the chart
(Point A) and follow this value upwards to the intersection with the
600A fuse curve (Point B). Follow this point horizontally to the left to
intersect with Line A-B (Point C). Read down to the bottom of the chart
(Point D) and read approximately 18,000 amps.

FUSE
AMPERE
RATING

200

Peak Let-through Charts for Littelfuse POWR-GARD™ fuses are shown in
each product section of this catalog. These charts are useful in determining
whether a given fuse can protect a specific piece of equipment.

B

100

Using the Peak Let-through Charts (“Up-Over-and-Down”)

PEAK LET-THRU IN AMPERES

The curves that branch off line A-B show the current-limiting effects
of different fuse ampere ratings. Enter the chart in Figure 14 on the
bottom at 100,000 rms symmetrical amperes and read upwards to
the intersection of the 200 ampere fuse curve. Read horizontally to the
left from this point and read approximately 20,000 amperes. The 200
ampere fuse has reduced the peak current during the fault from 230,000
amperes to 20,000 amperes. 20,000 amperes is less than one-tenth of
the available current. Magnetic force created by current flow is a function
of the peak current squared. If the peak let-through current of a currentlimiting fuse is one-tenth of the available peak, the magnetic force is
reduced to less than 1/100 of what would occur without the fuse.

1000000
800000
600000
400000
300000
200000

20000

600

Time-Delay
Normal Opening
Very Fast-Acting
Time-Delay
Normal Opening
Very Fast-Acting

Opening Time in Seconds
500% Rating 800% Rating 1200% Rating
12 secs.
0.9 secs.
0.14 secs.
2 secs.
0.7 secs.
0.3 secs.
1.3 secs.
0.02 secs.
>0.01 secs.
14 secs.
0.7 secs.
0.045 secs.
10 secs.
3 secs.
1.1 secs.
2 secs.
0.05 secs.
>0.01 secs.

3000
4000
6000
8000
10000

100

Fuse Type

2000

Ampere Rating

300
400
600
800
1000

Comparative Opening Times for Time-Delay,
Fast-Acting, and Very Fast-Acting Fuses

Current

Table 1

Figure 14
Peak Let-through Charts
nected to a system having 100,000 available rms symmetrical amperes.
This method, sometimes referred to as the “Up-Over- and-Down”
method, may be used to:
1. Provide back-up short-circuit protection to large air power circuit
breakers.
2. Enable non-interrupting equipment such as bus duct to be installed in
systems with available short-circuit currents greater than their shortcircuit (withstand) ratings.

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Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
Engineering Services Group at 1-800-TEC-FUSE (1-800-832-3873).
B

Ampere (Current) Rating
FUSE
AMPERE
RATING

100000
80000
60000
40000
30000
20000

600
400

B

C

200
100
60

10000
8000
6000
4000
3000
2000

30

1000
800
600
400
300
200

A

A fuse ampere rating is the AC or DC current that the fuse can
continuously carry under specified conditions. Fuses selected for a
circuit must have ampere ratings that meet NEC requirements. These
NEC requirements establish maximum ratings and, in some cases,
minimum ratings. NEC Articles 240 and 430 contain specific requirements.

Fuse Dimensions
There is a trend toward miniaturization in almost everything, and
electrical equipment is no exception. While saving space may be an
important factor when selecting the proper fuses, other considerations
should not be overlooked. Some of these are:
a) Does the smallest fuse have the most desirable characteristics for
the application?
b) Does the equipment in which the fuse will be installed provide
adequate space for maintenance?
c) Do smaller fuses coordinate well with the system’s other overcurrent
protection?

200000

3000
4000
6000
8000
10000

2000

300
400
600
800
1000

200

100

A
30000
40000
60000
80000
100000

D

100

20000

PEAK LET-THRU IN AMPERES

1000000
800000
600000
400000
300000
200000

General Fusing Recommendations

AVAILABLE FAULT CURRENT
SYMMETRICAL R.M.S. AMPERES

Fuse Ratings from 1/10 through 600 amperes
Figure 15
Peak Let-through Chart for POWR-PRO®
LLNRK Class RK1 Dual-Element Fuses.
Using the Up-Over-and-Down Method.
This method may not be used to select fuses for backup protection of
molded case or intermediate frame circuit breakers. National Electrical
Code® (NEC®) Article 240.86 states:
“Where a circuit breaker is used on a circuit having an available fault
current higher than its marked interrupting rating by being connected on
the load side of an acceptable overcurrent protective device having the
higher rating, 240.86(A) and (B) shall apply.
(A) Marking. The additional series combination interrupting rating shall be
marked on the end use equipment, such as switchboards and panelboards.”
NEC Article 110.22 states:
“Where circuit breakers or fuses are applied in compliance with the series
combination ratings marked on the equipment by the manufacturer, the
equipment enclosure(s) shall be legibly marked in the field to indicate
the equipment has been applied with a series combination rating. The
marking shall be readily visible and state the following:
CAUTION - SERIES COMBINATION SYSTEM RATED ________
____ AMPERES. IDENTIFIED REPLACEMENT COMPONENTS
REQUIRED.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fast-acting JLLN/JLLS series Class T fuses possess space-saving
features that make them especially suitable for protection of molded
case circuit breakers, meter banks, and similar limited-space applications.
Time-delay JTD_ID/JTD series Class J fuses are used in OEM motor
control center applications as well as other MRO motor and transformer
applications requiring space-saving IEC Type 2 protection.
Class CC and Class CD series fuses are used in control circuits and
control panels where space is at a premium. Choose Littelfuse POWRPRO CCMR series fuses for protection of small motors. They are now
available with ampere ratings up to 60 amperes. Choose Littelfuse
KLDR series fuses for the protection of control power transformers and
similar devices.
Should you have any questions concerning product applications, call our
Technical Support Group at 800 TEC FUSE.

Fuseology

UL Listed fuse-to-circuit breaker series ratings are now available from
most national loadcenter and panelboard manufacturers. The Listings
are shown in their product digests and catalogs. Many local builders
have also obtained fuse-to-circuit breaker series ratings. For additional
information on this subject contact the Littelfuse Technical Support and

When available fault currents are less than 100,000 amperes and when
equipment does not require the more current-limiting characteristics of
RK1 fuses, POWR-PRO FLSR_ID series Indicating Class RK5 currentlimiting fuses provide superior time-delay and cycling characteristics
along with all the benefits of an indicating fuse at lower cost than
RK1 fuses. FLSR_ID series fuses tell you when they have protected
your circuit and need to be replaced. If available fault currents exceed
100,000 amperes, equipment may need the additional current-limitation
capabilities of the POWR-PRO LLNRK/LLSRK/LLSRK_ID series Class
RK1 fuses.

Fuses with ampere ratings from 601 through 6,000 amperes
For superior protection of most general-purpose and motor circuits, we
recommend POWR-PRO KLPC series Class L fuses.

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189

Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
Coordinated (Selective) Systems
A “coordinated” or “selective” system is a system whose overcurrent
protective devices have been carefully chosen and their time-current
characteristics coordinated. Only the overcurrent device immediately on
the line side of an overcurrent will open for any overload or short-circuit
condition.

KLPC
3000

See definition of Selective Coordination in Definitions, and refer to
Figure 5 for a graphical example.

KLPC
1500

KLPC
1200

KLPC
1000

When a system is not coordinated, a fault at X might cause Fuse
B to open. This increases the amount of equipment out of service,
and makes it more difficult to locate the problem, thereby increasing
downtime.
Since the advent of electrical and electronic equipment, businesses
have become entirely dependent on the continuous availability of
electric energy. Loss of power halts all production. Customer service is
interrupted; order processing ceases; yet expenses continue.

LLSRK
400

For these and many other reasons, selectivity is the standard by which
many systems are judged.

Fuse Selectivity
Refer to Figure 11 which shows typical average melting time curves
for one class of fuses. Note that the curves are roughly parallel, and that
for a given overcurrent the smaller fuse ratings respond quicker than the
larger ratings. The heat energy required to open a fuse is divided into
melting I2t and arcing I2t (see definition of Ampere-Squared-Seconds).
The sum of these is the total clearing I2t.
For a system to be coordinated, the smaller fuse total clearing I2t
must be less than the larger fuse melting I2t. Put another way, if the
downstream (branch) fuse opens the circuit before the overcurrent
affects the upstream (feeder) fuse element, the system will be
selective. This can be determined from curves showing melting and
total clearing I2t, or from minimum melting and maximum clearing timecurrent curves.

Fuseology

The simplest method of coordinating low voltage power fuses is by use
of a Coordination Table such as the one shown in Table 2. This table is
only applicable for the Littelfuse POWR-PRO® and POWR-GARD™ fuse
series listed. Tables such as this one greatly reduce design time. For
example, the coordination table shows that POWR-PRO KLPC Class L
fuses coordinate at a two-to-one ratio with other Class L fuses, and
with POWR-PRO LLNRK/LLSRK/LLSRK_ID series Class RK1 and
POWR-PRO JTD/JTD_ID series Class J fuses.

190

LLSRK
200

LLSRK
200

Figure 16
A Coordinated (selective) Fused System

Even many UPS systems become unintentionally non-selective, causing
power loss to computers and other critical equipment. Non-selectivity
may defeat otherwise well-engineered UPS systems.
In a selective system, none of this occurs. Overloads and faults are
disconnected by the overcurrent protective device immediately on the
line side of the problem. Minimum equipment is removed from service,
the faulted or overloaded circuit is easy to locate, and minimum time is
required to restore full service.

LLSRK
400

In the system shown in Figure 16, the 3000 amp Class L main fuses
are at least twice the ratings of the 1500, 1200, and 1000 amp Class L
feeder fuses, therefore they will coordinate. The Coordination Table also
shows that the LLSRK series time-delay RK1 feeder and branch circuit
fuses coordinate at a two-to-one ratio with the Class L feeder fuses, so
the entire system in Figure 16 would be 100% coordinated.

Circuit Breaker Coordination
Because of the many types of circuit breakers and circuit breaker trip
units, developing a coordinated circuit breaker system or coordinating
circuit breakers with fuses is beyond the scope of this Guide. If you have
questions concerning these subjects contact the Littelfuse Technical
Support Group. For more information on fuses and circuit breakers
request Littelfuse Tech Topics Volume 2 – Fuses Vs. Breakers (PF327).

Component Short-Circuit Protecting Ability
NEC requires equipment protection to be coordinated with overcurrent
protective devices and available fault current to prevent extensive
damage to equipment. See Figure 17. Essentially, this means
that electrical equipment must be capable of withstanding heavy
overcurrents without damage or that they are protected by overcurrent
protective devices that will limit damage.
When a severe fault occurs in an unprotected circuit, current
immediately increases to a very high value. This is the available or
prospective fault current. Some fuses respond so quickly to the
increasing current that they interrupt current within the first half-cycle;
before the current reaches its first peak. See Figure 13. Such fuses are
termed “current-limiting fuses.” Current-limiting fuses stop damaging
current faster than any other protective device. Current-limiting fuses
greatly reduce or totally prevent component damage from high fault
currents. This helps meet the NEC® Article 110.10 requirements shown
in Figure 17.

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Fuseology

Fuse Application Guide
Overcurrent Protection Fundamentals
Table 2
Fuse Coordination Table
Selecting the Correct Fuse Ampere Ratio to Maintain Selectively Coordinated Systems
Ratios are expressed as Line-Side Fuse to Load-Side Fuse
Line-Side Fuses

Ampere
Range

601-6000
601-4000
601-2000
30-600
30-600
30-600
30-600
30-600
30-600
30-600
30-600
30-1200
30-1200
30-600
1-60

UL Class

L
L
L
RK1
RK1
J
RK5
RK5
RK5
RK1
RK1
T
T
J
G

Load-Side Fuses

Littelfuse
Catalog No.

KLPC
KLLU
LDC
LLNRK
LLSRK_ID
JTD_ID
IDSR
FLNR_ID
FLSR_ID
KLNR
KLSR
JLLN
JLLS
JLS
SLC

601-6000
L

Time-Delay Fuses
Ampere Range, UL Class and Catalog No.
601-4000
30-600
30-600
L
RK1
J

KLPC
LDC

KLLU

LLNRK
LLSRK_ID

JTD_ID
JTD

2:1
2:1
2:1
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A

2:1
2:1
2:1
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A

2:1
2:1
2:1
2:1
2:1
2:1
1.5:1
1.5:1
1.5:1
3:1
3:1
3:1
3:1
3:1
3:1

2:1
2:1
2:1
2:1
2:1
2:1
1.5:1
1.5:1
1.5:1
3:1
3:1
3:1
3:1
3:1
3:1

30-600
RK5
FLNR_ID
FLSR_ID
IDSR
4:1
4:1
4:1
8:1
8:1
8:1
2:1
2:1
2:1
8:1
8:1
8:1
8:1
8:1
4:1

Fast-Acting Fuses
Ampere Range, UL Class and Catalog No.
30-600
30-1200
30-600
1-60
RK1
T
J
G
KLNR
KLSR

JLLN
JLLS

JLS

SLC

2:1
2:1
2:1
3:1
3:1
3:1
1.5:1
1.5:1
1.5:1
3:1
3:1
3:1
3:1
3:1
2:1

2:1
2:1
2:1
3:1
3:1
3:1
1.5:1
1.5:1
1.5:1
3:1
3:1
3:1
3:1
3:1
2:1

2:1
2:1
2:1
3:1
3:1
3:1
1.5:1
1.5:1
1.5:1
3:1
3:1
3:1
3:1
3:1
2:1

N/A
N/A
N/A
4:1
4:1
4:1
1.5:1
1.5:1
1.5:1
4:1
4:1
4:1
4:1
4:1
2:1

NATIONAL ELECTRICAL CODE®

ARTICLE 110 – REQUIREMENTS FOR ELECTRICAL INSTALLATIONS
A. General
110-3. Examination, Identification, Installation, and Use of Equipment.
(A) Examination. In judging equipment, considerations such as the following shall be evaluated:
(5) Heating effects under normal conditions of use and also under abnormal conditions likely to arise in service.
(6) Arcing effects.
(B) Installation and Use. Listed or labeled equipment shall be used or installed in accordance with any instructions included in the listing or
labeling.

110.9 Interrupting Rating. Equipment intended to interrupt current at fault levels shall have an interrupting rating sufficient for the nominal
circuit voltage and the current that is available at the line terminals of the equipment.
Equipment intended to interrupt current at other than fault levels shall have an interrupting rating at nominal circuit voltage sufficient for the
current that must be interrupted.
110.10 Circuit Impedance and Other Characteristics. The overcurrent protective devices, the total impedance, the component shortcircuit current ratings, and other characteristics of the circuit to be protected shall be selected and coordinated to permit the circuit-protective
devices used to clear a fault to do so without extensive damage to the electrical components of the circuit. This fault shall be assumed to
be either between two or more of the circuit conductors or between any circuit conductor and the grounding conductor or enclosing metal
raceway. Listed products applied in accordance with their listing shall be considered to meet the requirements of this section.

ARTICLE 240 – OVERCURRENT PROTECTION
240.1 Scope. Parts I through VII of this article provide the general requirements for overcurrent protection and overcurrent protective devices
not more than 600 volts, nominal. Part VIII covers overcurrent protection for those portions of supervised industrial installations operating at
voltages of not more than 600 volts, nominal. Part IX covers overcurrent protection over 600 volts, nominal.
(FPN): Overcurrent protection for conductors and equipment is provided to open the circuit if the current reaches a value that will cause an
excessive or dangerous temperature in conductors or conductor insulation. See also Sections 110.9 for requirements for interrupting ratings and
110.10 for requirements for protection against fault currents.
Fuseology

(Reproduced by permission of NFPA)

Figure 17
National Electrical Code Requires Effective Overcurrent Protection

© 2005 Littelfuse • POWR-GARD™ Products Catalog

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191

Fuseology

Fuse Application Guide
UL/CSA Fuse Charts
Fuses for Supplementary Overcurrent Protection
Standards:
UL Standard 248-14 (formerly 198F); CSA Standard C22.2,
No. 59-1. Three Classifications covered:
Note: Fuses may be rated for AC and/or DC when suitable for such use.
(1) Micro fuses
Voltage ratings:
UL, 125 volts; CSA, 0-250 volts
Current ratings:
UL, 0-10 amps; CSA, 0-60 amps
Interrupting rating:
50 amps rms symmetrical
(2) Miniature fuses (CSA classifies these as Supplemental Fuses)
Voltage ratings:
UL, 125 or 250 volts; CSA, 0-600 volts
Current ratings:
UL, 0-30 amps; CSA, 0-60 amps
Interrupting rating:
10,000 amps rms symmetrical
(3) Miscellaneous Cartridge fuses (CSA classifies these as Supplemental Fuses)
Voltage ratings:
UL, 125 to 600 volts; CSA, 0-600 volts
Current ratings:
UL, 0-30 amps; CSA 0-60 amps
Interrupting ratings: 10,000, 50,0000, or 100,000 amps rms symmetrical
Time delay (Optional); Minimum delay at 200% fuse rating:
5 seconds for fuses rated 3 amps or less
12 seconds for fuses rated more than 3 amps

Special Purpose Fuses
There are no UL Standards covering this category of fuses. These fuses have special
char ac teris tics designed to protect special types of electrical or electronic equipment
such as diodes, SCR, transis tors, thyristers, capacitors, integrally fused circuit breakers, parallel cable runs, etc. Fuses may be UL Recognized for use as a component in UL
Listed equipment. UL Recognized fuses are tested for char ac teris tics such as published
interrupting capacity. They are also covered by UL re-examination service.
Non-renewable
Voltage ratings:
to 1000 volts AC and/or DC
Ampere ratings:
to 6000 amperes
Interrupting ratings:
to 200,000 amperes
Dimensions vary widely depending on application, voltage and current ratings.
Many of these fuses are extremely current limiting. When considering application of
these fuses, or if you have special requirements, contact Littelfuse Technical Support
Group for assistance.
LF Series:
KLC, LA15QS, LA30QS, LA50QS, LA60QS, LA60X, LA70QS, LA100P,
LA120X, LA070URD, LA130URD, L15S, L25S, L50S, L60S, L70S, JLLS 900 amp through
1200 amp

LF Series: BLF, BLN, BLS, FLA, FLM, FLQ, KLK, KLKD (600 Volts DC)
NOTE: Littelfuse electronic fuses are also covered by these standards; see electronic
section of this catalog, or request Electronic Designer's Guide
(Publication No. EC101) for complete listing.

Fuses for overcurrent and short-circuit protection of
power and lighting feeders and/or branch circuits

Current Limiting

Non-Current Limiting

Plug Fuses
UL Standard 248-11 (formerly 198F),
CSA Standard C22.2, No. 59.1
Voltage ratings:
125 volts AC only
Current ratings:
0-30 amps
Interrupting ratings:
10,000 amps rms symmetrical. Inter rupting rating need not
be marked on fuse.
Two types: Edison-base and Type S
Edison-base: Base is same as standard light bulb. All amp ratings interchangeable.
NEC permits Edison-base plug fuses to be used only as replacements for existing
fuses, and only when there is no evidence of tampering or overfusing.
Type S: Not interchangeable with Edison-base fuses unless non-removable type S
fuse adapter is installed in Edison-base fuse socket.
To prevent overfusing, adapters have three ampere ratings: 10-15, 16-20,
and 21-30 amps.
Time delay: Fuses may be time delay, if so, they are required to hold 200% of rating for
12 seconds minimum.
Time delay plug fuses are marked T, TD, o r Time Delay
NOTE: Plug fuses may be used where there is not more than 125 volts between conductors or more than 150 volts from any conductor to ground. This permits their use in
120/240 volts grounded, single-phase circuits.
Standards:

Edison-base: TOO, TLO
Type S: SOO, SLO
Type S Adapters: SAO

ONE-TIME FUSES
(NON-RE NEWABLE)
Time delay: Optional
Time-delay fuses must hold 500%
current rating for a minimum of ten
seconds
LF Series:

NLKP

RENEWABLE FUSES
Only Class H fuses may be renewable.
While time delay is optional, no
renewable fuses meet require -ments
for time delay.
Some renewable fuses have a
moderate amount of time delay,
referred to as “time lag” to
differentiate from true time delay.
LF Series:
RLN, RLS
Replaceable links Series: LKN, LKS

Fuseology

LF Series:

CLASS H
UL Standard 248-6 (formerly 198B),
CSA Standard C22.2, No. 59.1
Also known as NEMA Class H, and sometimes referred to as “NEC” or “Code” fuses
Voltage ratings:
250 and 600 volts, AC
Current ratings:
0-600 amps
Interrupting ratings:
10,000 amps rms symmetrical
Two types: one-time and renewable
Physically interchangeable with UL Classes K1 & K5;
Fits UL Class H fuseholders which will also accept K1, K5, RK5, and RK1 fuses.
Manufacturers are upgrading Class H One-time fuses to Class K5 per UL Standard 198D,
See Class K fuses.
Standards:

192

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Fuseology

Fuse Application Guide
UL/CSA Fuse Charts
CURRENT LIMITING FUSE LABELING
Fuses which meet the requirements for current limiting fuses are required to be labeled
“Cur rent Limiting”. Fuse labels must include: UL/CSA fuse class, Manufacturer's name or
trademark, Current Rating, AC and/or DC voltage rating, and AC and/or DC interrupting
rating. The words “Time Delay” or equivalent may also be included on the label when
the fuse complies with time delay requirements of its class.

CLASS G
UL Standard 248-5 (formerly 198C),
CSA Standard C22.2, No. 106, classified as HRC1 Misc.
Voltage rating:
480 volts, AC
Current ratings:
0-60 amps
Interrupting rating:
100,000 amps rms symmetrical
Not interchangeable with any other UL fuse class.
Time delay optional: Minimum of 12 seconds at 200% current rating.

Standards:
Voltage ratings:
Current ratings:

CLASS T
UL Standard 248-15 (formerly 198H),
CSA Standard C22.2, No. 106, classified as HRCI-T
300 and 600 volts AC, 125 and 300 volts DC
0-1200 amps
900 to 1200 amps UL Recognized for 600V version
200,000 amps rms symmetrical

Interrupting rating:
Non-renewable
Fast-Acting fuses. High degree of current limitation
Very small fuses; space-saving and non-interchangeable with any other fuse class.

Standards:

LF Series:

SLC

CLASS J
UL Standard 248-8 (formerly 198C),
CSA Standard C22.2, No. 106, classified as HRCI-J
Voltage rating:
600 volts, AC
Current ratings:
0-600 amps
Interrupting rating:
200,000 amps rms symmetrical
Not interchangeable with any other UL fuse class
Time delay optional: Minimum of 10 seconds at 500% current rating.
Standards:

LF Series:

Time-Delay: JTD_ID, JTD
Fast-Acting: JLS

CLASS L
UL Standard 248-10 (formerly 198C),
CSA Standard C22.2, No. 106, classified as HRCI-L
Voltage rating:
600 volts, AC and/or DC
Current ratings:
601-6000 amps
KLPC also available 200-600A; LDC also available 150-600A
Interrupting rating:
AC: 200,000 amps rms symmetrical
DC: 50,000, 100,000, or 200,000 amps
Not interchangeable with any other UL fuse class
Time delay: Class L fuses may be marked “Time-Delay” although UL does not investigate
time-delay characteristics of Class L fuses.
KLPC & KLLU:
10 seconds at 500% current rating.
LDC:
4 seconds at 500% current rating
Standards:

LF Series:

Standards:

LF Series:

JLLN/JLLS

CLASS CC/CD
UL Standard 248-4 (formerly 198C),
CSA Standard C22.2, No. 106, classified as HRCI Misc.
Voltage rating:
600 volts, AC
Current ratings:
UL Class CC; 0-30 amps
UL Class CD: 35-60 amps
Interrupting ratings:
200,000 amps rms symmetrical
Non-renewable
Fuseholders:
Fit UL Class CC and CD fuseholders which reject non Class CC fuses.
Time delay optional: Minimum of 12 seconds at 200% current rating.
Standards:

LF Series:

KLKR (Fast-Acting)
KLDR (Time-Delay for Transformers)
CCMR (Time-Delay for Motors)

CLASS K
Standards: UL Standard 248-9 (formerly
198D), No CSA Standard
Voltage ratings: 250 and 600 volts, AC
Current ratings: 0-600 amps
Interrupting ratings: Three permitted:
50,000, 100,000, and 200,000 amps rms sym
Non-renewable
Time delay is optional for Class K fuses.
Fuses marked “Time Delay”, “D” or “TD” are
required to hold 500% current rating for a
minimum of ten seconds.
Same Dimensions and Physically
Interchangeable with UL Class H fuses
Fits UL Class H fuseholders
Class K fuses are not permitted to be labeled
Current Limiting because there is no rejection
feature as required by NEC Article 240-60(B).

CLASS K1
Same prescribed degree of
current limitation as RK1 fuses
when tested at 50,000 or
100,000 amps rms symmetrical.
LF Series:
Time Delay – Use LLNRK/LLSRK
Fast-Acting – Use KLNR/KLSR
CLASS K5
Same prescribed degree of
current limitation as RK5 fuses
when tested at 50,000 or
100,000 amps rms symmetrical.
LF Series:

NLN/NLS

KLPC, KLLU, LDC

CLASS R
UL Standard 248-12 (formerly 198E),
CSA Standard C22.2, No. 106, classified as HRCI-R
250 and 600 volts, AC; 125 and 300 volts DC
0-600 amps
200,000 amps rms symmetrical
RK1 & RK5

© 2005 Littelfuse • POWR-GARD™ Products Catalog

LF Series:

Time Delay: LLNRK, LLSRK, LLSRK_ID
Fast-Acting: KLNR, KLSR

CLASS RK5
Moderate degree of current limitation, adequate for most applications.
Time Delay optional
FLNR_ID, FLSR_ID and IDSR series provides visual indication of blown fuse.
LF Series:

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Fuseology

Voltage ratings:
Current ratings:
Interrupting rating:
Two classes:
Non-renewable
Time delay is optional for Class R fuses.
Fuses marked “Time Delay”, “D”, “TD”, or similar indications of time delay are required
to hold 500% current rating for a minimum of ten seconds.
Same Dimensions as UL Class H fuses, terminals modified to provide rejection feature.
Fits UL Class R fuseholders which reject non Class R fuses.
Physically interchangeable with UL Class H, NEMA Class H, and UL Classes K1 & K5
when equipment has Class H fuseholders.

CLASS RK1
High degree of current limitation.
Provides IEC Type 2 (no damage) protection for motor starters and control components
Time Delay optional LLSRK_ID Series provides visual indication of blown fuse

FLNR_ID, FLSR_ID and IDSR

193

Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications
Fuses for Specific Applications (600 volts and Below)
INDEX
Page
Protecting Service Entrance and Feeder Conductors ..... 194
Motor Protection ........................................................................ 194-198
Motor Overload Protection (running overcurrent) ............... 195-196
Motor Feeder (100% motor Load) over 600A.................... 197
Motor Branch Circuit Protection over 600A. ....................... 197
Motor Controller (Starter) Protection over 600A. ............... 197
Control Circuit Protection ...................................................... 197
Control Transformer Protection ............................................ 197-198
Protecting Branch Circuits....................................................... 198
Transformer Protection............................................................. 198
Primary Fusing only ............................................................... 198
Primary Fusing With Secondary Fusing .............................. 198
Secondary Fusing of Transformers ...................................... 198
Fusing Capacitors ....................................................................... 198
Lighting Fixture Protection ...................................................... 198

If the largest motor has a long acceleration time requiring branch circuit
protection to be increased to 175-225% of FLA, it may be necessary
to increase main and feeder fuse ratings to 175-225% of the largest
motor FLA plus the other current values as indicated above. However,
if conductor ampacity has been increased to provide spare capacity
for future loads, fuse ratings may be increased to the ampacity of the
conductors.

Street Lighting and Other Weatherproof
........ Overcurrent Protection ................................................. 198
Cable Short-Circuit Protection (Cable Limiter Application) .199
Semiconductor and Solid-state Device Protection .......... 199

Main Services and Feeders 600 amps and less

Medium Voltage Protection ..................................................200-203

Protecting Service Entrance and Feeder Conductors
601 through 6000 amperes
Select POWR-PRO® KLPC series Class L fuses for AC circuits from 601
through 6000 amperes. The construction and operating characteristics
of KLPC series fuses meet the toughest project specifications for Class
L fuses:
•
•
•
•

They provide maximum time-delay and current-limitation.
They have a 300,000 amp interrupting rating.
They have an “O-ring” seal to improve short-circuit performance.
The fuse links are 99% pure silver.

If the system has DC circuits, another choice is the POWR-PRO LDC
series Class L fuses for AC and DC circuits available from 601 through
2000 amperes. LDC series fuses are the only Class L fuses which are
UL Listed at both 600 Volts AC and DC. When facilities have a mix of
large AC and DC circuits, standardizing on LDC series for all Class L
fuses should be considered. This reduces inventory and eliminates the
possibility that an AC-only fuse will be used in a DC circuit.
When conductors are selected in accordance with the NEC®,
recommended fuse ratings for mains and feeders with combined motor
and non-motor loads are:

Fuseology

•
•
•
•

150% of the largest motor full load current plus,
100% of all other motors full load currents plus,
125% of the continuous1 non-motor load plus,
100% of non-continuous, non-motor load.

When standard fuse ratings do not match conductor ampacities, the
next larger standard fuse ratings may be used only if they are rated
less than 800 amperes. If fuse ratings are over 800 amperes, the next
smaller ratings must be used. In addition to all standard ampere ratings,
KLPC and LDC series fuses have many additional ampere ratings. The
additional ratings permit minimum downsizing of fuses, saving valuable
conductor ampacity.

Several fuse series may be used for main services and feeders under
600 amperes. Choices should be made on the needs of the particular
facility. Some of the needs to be considered are discussed below, with
recommendations for fuses that meet those needs.
The vast majority of electrical systems, especially those 600 amps and
smaller, have available short-circuit currents less than 100,000 amperes.
Class RK5 fuses have provided excellent protection for such circuits
for many years. When fault currents exceed 100,000 amperes at the
service entrance, a study should be made to determine if the additional
current limitation provided by Class RK1 or Class J fuses is required.
POWR-PRO Class RK5, 600 Volt FLSR_ID series Indicator® fuses
provide superior time-delay plus substantially better current limitation
than required by UL Class RK5 standards. In addition, the patented
indicating window on the fuse immediately shows which fuses are
blown. This can significantly reduce downtime.
POWR-PRO Class RK1, 250/600 Volt LLNRK/LLSRK/LLSRK_ID series
time-delay fuses are the fuse of choice for circuits where fault currents
exceed 100,000 amperes. The LLSRK advanced design reduces shortcircuit damage to full-size NEMA and sensitive IEC motor controllers, and
is capable of providing Type 2 “No Damage” protection to NEMA size
motor starters. Together with the KLPC series fuses, the LLNRK/ LLSRK
series form the foundation of the POWR-PRO Fuse system of overcurrent
protection. And, the patented indicating window on the LLSRK_ID series
provides the same benefits of blown fuse indication for the user.
POWR-PRO Class J 600 Volt JTD_ID series time-delay fuses provide
the amount of time-delay necessary for most applications and are
substantially smaller than RK5 or RK1 fuses with current-limitation equal
to the RK1 fuse. JTD_ID series fuses provide IEC Type 2 “No Damage”
protection to both NEMA and IEC control components and motor
controllers. When time-delay is required and space is the determining
factor, JTD_ID time-delay Class J fuses provide the answer.

1 See Definitions for “Continuous Load.”

194

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications
When conductors are selected in accordance with the NEC®,
recommended fuse ratings for mains and feeders rated 1 to 600A with
combined motor and non-motor loads are:
•
•
•
•

Motor Running Current
Full Load Amperes (FLA or F.L.A.): A motor’s rated full load amps

150% of the largest motor full load current plus,
100% of all other motors full load currents plus,
125% of the continuous1 non-motor load plus,
100% of non-continuous, non-motor load.

(full load current) is the motor’s running current when connected to a
load equal to its horsepower rating. If load exceeds the horsepower
rating, current will exceed the FLA and the motor may overheat. The
vast majority of motors are only partially loaded. As load decreases,
motor current decreases.

Motor Protection
The importance of effective motor and motor circuit protection cannot
be over emphasized. Motors are consistently the largest single cause of
industrial and commercial fires.
In today’s highly automated commercial and industrial facilities, the
failure of even one relatively minor motor may shut down an entire
installation.

Motor Characteristics
Motors discussed herein are standard characteristic AC induction
motors, which cover about 80-85% of all motors. Special purpose
motors are beyond the scope of this publication. Specific application
information and protection requirements for these special purpose
motors should be obtained from the motor manufacturers.

Horsepower Ratings
A motor’s assigned horsepower rating indicates the work that it can
do under standard test conditions. It is the maximum horsepower load
the motor can drive over a long period without exceeding its rated
temperature rise. However, a motor can develop far more horsepower
than its rating, and if the overload does not last long enough to overheat
the motor, no damage occurs.
A motor tries to rotate any load attached to it. If the load is too large,
the motor will not be able to rotate and will overheat and fail within a
very short period. However, if the motor is able to start and run with
an overload, excess heat will be generated. If the motor is not stopped
or the overload removed, the excess heat will gradually deteriorate the
insulation, and the motor will prematurely fail.

Motor RPM
The motor nameplate shows the rated speed of the motor in revolutions
per minute (RPM) with rated full load attached. The no-load speed of
the motor is somewhat higher. The no-load (synchronous) speed of a
motor is a function of its design and the number of poles (windings).
Table 3 shows the relationship between the number of poles, no-load
speed, and full load speed shown on the motor nameplate.

Table 3
Synchronous (No Load) Speed of Induction Motors vs Full Load Speed
Number of Poles

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Typical Full Load
Speed Range (RPM)
3450 – 3500
1710 – 1760
855 – 880
520 – 610

Partially Loaded Motors: If a motor is not connected to any external
load, it still requires a certain amount of current to turn the rotor. This
is defined as the “no-load amps” or “no-load current.” No-load current
is a constant for any given motor and does not change with load.
However, no-load current varies widely for different motor designs and
horsepower ratings.
A motor’s actual running current is the sum of no-load current and load
current. For all practical purposes, load current increases directly as the
load increases. If a motor is loaded to only 50% of rated horsepower,
then the actual load current will be approximately 50% of the full
potential load current.
If a given motor’s no-load current is 30% of FLA, load current is 70%
FLA (100% - 30% = 70%). At 50% rated load, the load current would
be about 35% FLA (one-half of 70%). Added to no-load current of 30%,
motor running current at 50% load will be about 65% FLA (30 + 35 =
65%). If the same motor were 75% loaded, the motor running current
would be about 83% FLA (0.70 X 0.75 + 0.30 = 0.83).

Motor starting currents: When a motor is first energized, a great
deal of energy (torque) is required to overcome the inertia of the motor
and the load. Once the load is moving, it requires much less energy to
keep it moving.
At the instant a motor is energized, motor current peaks at about 1215 times the nameplate FLA. This is the current required to magnetize
the motor windings. Within 1/ 2 to 3 / 4 cycles (0.008-0.0125 seconds)
the full magnetic field is developed, and current decreases from 12 to
15 times FLA to roughly 4.5 to 8 times FLA. This is called the motor
starting current, and is also the current the motor will draw if it stops
while energized. This is why it is also referred to as the locked-rotor
amps (LRA).
The exact value of LRA is determined by motor design, and is shown
on the motor nameplate by the NEMA design letter. Motors designed
to start only low inertia loads have the lowest starting current. Motors
with the same horsepower ratings but designed to start very high
inertia loads such as large flywheels, hammer mills, etc., will have much
higher starting currents. Table 4 shows the starting current for various
designs.
As the motor speed increases from zero, current remains high until
the motor reaches about 85-90% full speed. Current then begins to
decrease, and when the motor reaches full speed for the attached load,
current decreases to normal running current.

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Fuseology

2
4
8
12

Synchronous (No Load)
Speed (RPM)
3600
1800
900
600

All non-synchronous induction motors begin to slow down as the load
increases. This is commonly referred to as “slip.” As load increases, the
motor current and slip increase.

195

Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications
Table 4
Starting Current (Amperes) for Various Types of Motor Designs
Locked
NEMA
Rotor
Code
KVA Per
Letter
Hrspwr.
A
B
C
D
E
F
G
H
J
K
L
M
N
P
R
S
T
U
V

3.14
3.54
3.99
4.49
4.99
5.59
6.29
7.09
7.99
8.99
9.99
11.19
12.49
13.99
15.99
17.99
19.99
22.39
24.00

Maximum Locked Rotor Amps
for NEMA Code Letter Motors
Single Phase
115V
27.3
30.8
34.7
39.1
43.4
48.6
54.7
61.7
69.5
78.2
86.9
97.4
108.7
121.7
139.1
156.5
173.9
194.8
208.8

230V
13.7
15.4
17.4
19.5
21.7
24.3
27.4
30.8
34.8
39.1
43.5
48.7
54.3
60.9
69.6
78.3
87.0
97.4
104.4

Three Phase
200V
9.1
10.2
11.5
13.0
14.4
16.2
18.2
20.5
23.1
26.0
28.9
32.3
36.1
40.4
46.2
52.0
57.8
64.7
69.4

230V
7.9
8.9
10.0
11.3
12.5
14.0
15.8
17.8
20.1
22.6
25.1
28.1
31.3
35.1
40.1
45.2
50.2
56.2
60.2

460V
4.0
4.5
5.0
5.7
6.3
7.0
7.9
8.9
10.1
11.3
12.6
14.1
15.7
17.6
20.1
22.7
25.2
28.2
30.2

575V
3.1
3.5
4.0
4.5
5.0
5.6
6.3
7.1
8.0
9.0
10.0
11.2
12.5
14.0
16.0
18.0
20.0
22.4
24.0

Single-phasing of three-phase motors
Three phase motors are designed to operate with three balanced
phases. When one phase is missing, severe damage may occur if
the motor is not rapidly de-energized. This may be due to an open
wire in a motor junction box, an open motor winding, a blown fuse, a
burned contact in a motor controller, a defective circuit breaker, or other
conditions. What happens when single-phasing occurs depends on
the nature of the circuit. There are several possibilities which must be
examined to fully understand the problem:

A motor that is loaded to less than 50-60% load will not slow down
significantly while the current increases to 173% of the current being
drawn just prior to single-phasing. Since this is less than FLA, ordinary
running overcurrent protection will not sense this as an abnormal
condition and the motor will continue to run. When it stops, it will
obviously not restart again until the source of the single-phasing is
eliminated. Fortunately, the extra heat generated under these singlephase conditions can usually be dissipated by the motor. Little damage
is done, unless the single-phasing continues for an extended period of
time. For added protection to large, expensive motors, (especially those
over 600 volts), consideration should be given to installation of singlephase detection or voltage imbalance relays.
It is the group of motors loaded from 55-60% through 80% that
present the greatest challenge. When these motors are single-phased,
they slow down but continue to rotate. Current in the energized legs
increases to approximately 200-220% of current being drawn at the
time the motor was single-phased. This is a combination of the increase
due to single-phasing (173%) plus that due to slow down (slip increase).
Since this may vary from slightly less than FLA, up to as much as 200%
FLA, standard overcurrent protection may not provide adequate protection
when sized in accordance with rated full load amps of the motor.
The voltage imbalance in the circuit may also result in extra heat. This
additional heat produces damage in excess of that produced by current
alone.
The best way of reducing this type of damage is to measure the actual
current drawn by the motor under normal conditions, determine if
there may be temporary overloads that need to be considered, and
size overcurrent protection just large enough to permit the motor to run
under normal conditions.

Open circuit

When there is only one motor on a circuit which is singlephased
If the motor is not running at the time, and then tries to start while
single-phased, it will not have sufficient available energy to overcome
starting inertia, and will stay in a locked rotor condition. The motor will
draw full locked rotor current, and most overcurrent protection devices
will open the circuit quick enough to prevent serious motor damage.

3

motor

1

motor

3

1 HP
motor

Open circuit

Fuseology

If the motor is running at the time it is single-phased, current in the
remaining legs theoretically increases to 1.73 times the current being
drawn when the single-phasing occurs. Single-phased motors, however,
do not have the capability of developing full horsepower and torque, so
the motors may begin to slow down (increased slip) depending on the
amount of load. The motor is designed to operate at full speed, so the
current increases as the slip increases.
A motor that is more than 80% fully loaded at the time of single-phasing
will slow down quite rapidly and stop. Current increases to locked rotor
values, and the running overcurrent protection will de-energize the
circuit in sufficient time to protect the motor from significant damage.

196

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3

10 HP
motor
Figure 18

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications
Several motors single-phased on one circuit
When there is more than one motor on a circuit that is single-phased,
the effects on motor current depend on the relative size of the motors,
and whether they are all three-phase, or whether there is a mix of threephase and single-phase motors.

For general purpose motors with 1.15 service factor or 40° C rise, the
fuses may generally be rated at 125% of motor’s FLA. When fuse
ratings do not match the motor’s FLA, use the next larger standard
fuse rating, but do not exceed the NEC® limitation of 175% of motor’s
FLA as given in NEC Tables 430.248 through 430.250. Following these
guidelines will provide optimum protection to the circuit.

Figure 18 presents two such cases. In the circuit with a three-phase
and a single-phase motor, the three-phase motor was loaded to 70% of
full load. The feeder was then single-phased as shown. The currents in
the three-phase motor increased to 52%, 120%, and 36% of full load
current in the three phases. At 120% current, it is questionable whether
standard running overcurrent protection sized at 115% of rated FLA could
provide protection from damage due to overload and voltage imbalance.
When the circuit with the ten horsepower and one horsepower threephase motors was single-phased, the smaller motor did little to affect
the currents in the larger motor, but the one horsepower motor was
in serious trouble. One of the currents was 140% of normal, while
the other two currents were only slightly above the standard rating of
running overcurrent protection.
When the ampere rating of a motor’s running overcurrent protection
is based on the motor’s actual running current, adequate protection
may be provided for such conditions. However, as is usually the case,
if the ampere rating of a motor’s running overcurrent protection is
based on nameplate FLA and the motor is only partially loaded, the
protective devices (overload relays and fuses) may not open in time
to protect the motor because the current will not increase enough to
operate the relays.
For these reasons, and many others, it is strongly recommended that
Littelfuse POWR-GARD™ dual-element fuses be properly sized per the
recommended guidelines.

These recommendations will cover about 90% of all motor applications.
For those motors with especially severe starting duty and long
acceleration times, Table 430.52 of the NEC permits time-delay fuses to
be sized up to 175% of motor FLA.
If 175% of FLA will not permit the motor to start, fuse rating may be
increased to a maximum of 225% of motor FLA.
Pages 204 – 206 contain Motor Protection Tables that simplify the
selection of Littelfuse RK5, RK1, J and CC fuses for motor running
protection and motor branch short-circuit and ground fault protection.

Motor Feeders Over 600A With 100% Motor Load
Recommended fuses are POWR-PRO® KLPC series.
Recommended fuse ratings when conductors are selected in
accordance with the NEC are 150% of largest motor’s full load current
plus the full load current of the other motors. If required rating does not
correspond with a KLPC ampere rating, use the next larger rating.

Fuses for Mains and Feeders With No Motor Loads
Minimum fuse rating is 125% of the continuous load plus 100% of the
non-continuous load.

Protection required by motors
Since mains and feeders usually serve a mix of inductive and resistive
loads, time-delay fuses provide significant advantages. Even when there
is no motor load, time-delay fuses reduce other nuisance outages caused
by temporary overloads or switching surges. Available short-circuit current
is generally highest at the main service disconnect so that adequate
interrupting capacity and maximum current limitation are also desirable.

Motor Branch Circuits
Most motor circuits contain motor controllers (starters) which start and
stop the motor, overload relays to provide motor running protection, and
in some cases other relays to provide other types of protection.

Recommended ratings of RK1 and RK5 time-delay fuses for motor branch
circuits containing motor controllers with overload relays are as follows:

Fusing Motor Control Centers (MCCs)
The same general considerations apply to protecting MCCs as they do
to mains and feeders. Use time-delay current-limiting fuses as described
above to provide protection to the entire MCC including buses and
internal construction.
Feeders serving MCC are sized the same as general-purpose mains
and feeders since many MCC have both motor and non-motor loads.
Non-motor loads may include fused switches that serve dry-type
power transformers used for lighting panels or feeders to distribution
panels. MCC ampere ratings based on the MCC main buses usually
exceed the load connected to the MCC. Therefore, fuses feeding
the MCC or located in a main switch in the MCC may be rated to
protect the MCC buses, as long as they meet the minimum size as
determined above.

Fusing Control Transformers
With one exception, control transformers are protected the same as
regular transformers as discussed below. Control transformers with
primary current less than 2 amperes and which are part of a Listed
motor controller may have primary fusing not greater than 500% of
rated primary current.

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Fuseology

Time-delay fuses should be considered a must for motor branch circuits.
Motor starting currents and the possibility of temporary overloads
and/or voltage surges would require oversizing of non-time delay fuses
— often as much as 300%. In such cases, only short-circuit protection
is provided, and because of the oversizing necessary, larger switches
and enclosures are required. This is true of MCCs as well. Properly
selected, time-delay fuses also provide back-up protection to the motor
controllers for such conditions as single-phasing and contact welding.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

High efficiency motors and NEMA Design E motors have much higher
efficiencies, and also require higher locked rotor currents in relation
to FLA. They will require careful selection of both fuses and overload
relays. In these circuits, we recommend sizing fuses at 150% of FLA, or
the next smaller rating.

197

Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications
Protecting Branch Circuits
Multi-outlet branch circuits must be protected in accordance with the
ampere rating of the overcurrent protective device. Ratings shall be 15,
20, 30, 40, and 50 amperes, although non-lighting loads in industrial
facilities with adequate maintenance may have branch circuits larger than
50 amperes.
Special purpose branch circuits must have adequate capacity for the
load to be served. Refer to NEC® Article 210.2 for a listing of Articles and
Sections covering requirements for specific equipment not covered in this
section.

Transformer Protection
Transformers over 600 volts
The basic rule for transformers rated over 600 volts requires them to
have primary and secondary protection in accordance with Table 5.

Transformers rated 600 volts and less
UL Industrial Control Standards (No. 508) and Motor Control Center
Standards (No. 845) specify control power transformer protection
corresponding to NEC 430.72(C). In addition, UL requires the primary
of control power transformers used in controllers having short-circuit
ratings in excess of 10,000 amperes to be protected by UL Class CC,
J, R, or T fuses. For maximum fuse ratings permitted by the NEC,
refer to Table 6 for sizing of primary fusing and Table 7 for sizing of
secondary fusing.

Fusing Capacitors
Capacitors installed on the load side of motor running overcurrent
protection are required to have individual protection. All other capacitors
are required to have an individual fuse in each ungrounded conductor.
NEC Article 460.8(B) requires that the fuse rating be as small as
possible. Use POWR-PRO® dual-element time-delay fuses rated at
150% to 175% of capacitor rated current.

Table 5
Fuses for Transformers over 600 volts
Maximum Fuse Rating in Percent
of Transformer Rated Current
Transformer
Rated
Impedance

Primary
Fuse Rating
Over 600
Volts

Not more than
6%
More than 6%
and not more
than 10%

Secondary Fuse Rating
600 volts
Over
or less in
600 volts in
unsupervised
all locations
locations

600 volts
or less in
supervised
locations

300%

250%

125%

250%

300%

225%

125%

250%

Notes to Table 5
1. Littelfuse IDSR, LLNRK/LLSRK/LLSRK_ID, FLNR_ID/FLSR_ID, and JTD_ID series
time-delay fuses may be rated at 125% of transformer secondary current.
2. Where the required fuse rating does not correspond to a standard fuse rating, the
next higher standard rating is permitted.
3. An individual primary fuse is not required if the primary circuit fuse is not greater
than 300% of transformer primary current.

Table 6
Maximum Acceptable Rating of Primary Overcurrent Device
Rated Primary
Current Amperes

Less than 2
2 to less than 9
9 or more

Maximum Rating of Overcurrent Protective Device
% of Transformer Primary Current Rating
No secondary
fusing provided
3001
167
1252

Secondary fusing provided in
accordance with Table 7
2501
250
250

Table 7
Maximum Acceptable Rating of Secondary Overcurrent Device

Lighting Fixture Ballasts
Ballasts for all types of discharge lighting should be protected with
individual fuses. Even the newer electronic ballasts with internal fusing
benefit from fusing of the fixture. Individual fusing helps prevent loss of
an entire lighting circuit when one ballast or fixture fails. This prevents
loss of production. When only one fixture is removed from service, the
user can now identify the fixture in trouble and eliminate the need to
test all the fixtures to locate the problem. UL Listed Class P ballasts
are only tested at 200 amps fault current, and the test circuit has a fuse
ahead of the ballast. With available currents continuing to increase,
individual fixture fusing reduces the possibility of the ballast failing
in such a way that the fixture is damaged. Since ballast designs and
characteristics vary so much, recommendations for ballast fusing should
be obtained directly from the ballast manufacturer.
Fuseology

Fusing of Outdoor Lighting Standards
Whether the lighting fixtures are being used for highway lighting,
street lighting, or for parking lots, each fixture should be fused using a
Littelfuse Class CC or midget fuse installed in a LEB or LEC weather
proof fuseholder. These fuseholders were designed to fit in the base

198

Rated Secondary
Current Amperes

Maximum Rating of Overcurrent Protective Device
% of Transformer Secondary Current Rating

less than 9
9 or more

167
1252

Notes to Tables 6 & 7
1. 500% for Motor Circuit Control Power Transformers.
2. If 125% does not correspond to a standard fuse rating, the next higher standard
rating may be used.
Reference NEC 430.72 (c) Exception No. 2: 450.3 (b) 1 and 2 UL 508 32.7: 845 11.16
and 11.17.

of lighting standards. They withstand wet and corrosive conditions,
including those caused by snow-melting chemicals. Fusing each fixture
eliminates having to test the entire circuit for the faulted fixture when
only one fails. In industrial plants where outdoor lighting provides safety
and security, this is particularly important.

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Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications
Cable limiters have terminals which permit them to be installed in a
variety of equipment. The most common configuration is the offset
blade on one end and the crimp terminal on the other end. This permits
the limiter to replace a cable terminal (lug).

Cable Short-Circuit Protection
(application of cable limiters)
Cable limiters are fusible devices that provide very fast short-circuit
protection, primarily to faulted cables, but also to other conductors such as
busway. Cable limiters do not have an ampere rating, and cannot be used
to provide overload protection. Cable limiters are selected by cable size; for
example, a 500 kcmil cable requires a 500 kcmil cable limiter. Their main
use is to isolate faulted cables in circuits containing three or more parallel
conductors per phase and may be installed on the line side of the main
service to provide short-circuit protection to the service conductors. This is
especially important when service conductors are tapped from large low
voltage networks or from large low impedance transformers.
The principle involved is illustrated in Figures 19 and 20. The first
example has two cables per phase, as shown in Figure 19. When a
fault occurs in either cable as illustrated by the “X”, most of the fault
current will flow directly to the fault through limiter L-1. L-1 will open, and
all the fault current will back feed the fault via limiters L-3, L-4, and L-2.
Since all of the limiters have the same rating, they will all open resulting
in the entire circuit being shut down.
L-1

L-2

L-3

L-4

Applications
Service entrance conductors.
Between transformer or network bus and busway terminal boxes.
Large feeders with three or more conductors per phase.

Features/Benefits
• Fast-acting current-limiting characteristics provide protection to
conductor insulation and reduce damage when faults occur.
• Properly applied cable limiters may permit the use of equipment with
reduced withstand ratings.
• Wide variety of terminations and cable ratings permit use in almost
every situation.

Semiconductors and Solid-State Device Protection
Semiconductors generally are very sensitive to low value overloads and
to short-circuit currents. As a result, they require fuses referred to as
“very fast-acting” fuses. Littelfuse Semiconductor fuses are designed
specifically to protect power electronics equipment. For application
information refer to Littelfuse Semiconductor Application Guide PF336
or the Semiconductor fuse section of this catalog.

Effect Of Ambient Temperature On Fuses

L-1

L-2

L-3

L-4

L-5

L-6

60

KEY TO CHART:
Curve A - Slo-Blo® Fuse
Curve B - Medium and Fast-Acting Fuses

40

20

A

0

B

0

B

Figure 20
One Line Diagram of Circuit with Three or More Conductors Per Phase

40

A

© 2005 Littelfuse • POWR-GARD™ Products Catalog

60

-60°C

-40°C

-20°C

0°C

20°C

40°C

60°C

80°C

100°C

120°C

140°C

-76°F

-40°F

-4°F

32°F

68°F

104°F

140°F

176°F

212°F

248°F

264°F

www.littelfuse.com

Fuseology

By isolating faulted cables quickly, cable limiters prevent damage
to conductor insulation caused by the heating effects of large fault
currents. For example, if the cable run shown in Figure 20 passed
through pull boxes or manholes, and one section of the cable faulted,
only the faulted section would require replacement instead of one or
more entire lengths.

20

PERCENT OF DOWNRATING

However, when a fault occurs and there are three or more cables per
phase, this problem can be avoided. This scenario is illustrated in Figure
20. When a fault occurs at point “X”, current will flow directly to the
fault opening limiter L-1. The fault current will back feed the fault, but
when there are three or more conductors in parallel, it divides between
the remaining cables. When there are three conductors in parallel as
shown in Figure 20, one half of the fault current will flow through
limiters L-3 and L-4, and one-half will flow through limiters L-5 and L-6.
All of the fault current will flow through limiter L-2 causing it to open
before the other limiters. As a result, only the one cable is removed
from service.

The current carrying capacity of fuses is 110% of the fuse rating when
installed in a standard UL test circuit and tested in open air at 25°C
ambient. This allows for derating to 100% of rating in an enclosure at
40°C ambient. At higher ambient temperatures, the continuous current
carrying capacity will be decreased as shown in the chart below. This
closely follows the derating tables for all electrical equipment, and
can help reduce equipment burnout due to high ambient conditions.
Littelfuse SLO-BLO® or Time-Delay fuses derate quicker in higher
ambient conditions, so they in effect, act as “self-protecting” devices
and maintain their integrity until opening.

PERCENT OF UPRATING

Figure 19
One Line Diagram of Circuit with Two Conductors Per Phase

AMBIENT TEMPERATURE

Fuse Rerating Curve

199

Fuseology

Fuse Application Guide
Applying Fuses for Specific Applications/Applying Medium Voltage Fuses

Medium Voltage (MV) Fuse Application
(2,400 - 38,000 Volts AC)
Medium voltage fuses are applied quite differently than fuses rated 600
volts and less. The biggest difference is: medium voltage fuses are not
intended to provide overload protection. They should only be applied
where they will not be required to open small overcurrents. Another
major difference is the wide range of system voltages which results in a
correspondingly large number of fuse voltage ratings.

While not required for low voltage fuses, MV fuses maximum voltage
rating must also be considered. For a fuse to be current-limiting, it must
interrupt the circuit withing 180 electrical degrees (one-half cycle) after
the fault occurs. It does this by producing an arc voltage across the fuse
which is greater than the system voltage. This forces current to zero
before the available short-circuit current reaches its first peak.

Descriptions and ratings of Littelfuse medium voltage fuses are located
in the medium voltage fuse section of this catalog, which also contains
some application data. The following is a more detailed discussion of
factors which must be considered.

Arc voltages are created in the fuse by the melting of the fuse links. This
produces a number of high resistance arcs (gaps) in series, and there is
a voltage drop across each gap. When the total voltage drop exceeds
system voltage, current flow stops. As this occurs, a transient voltage
spike is generated in the system, (see Figure 21). Care must be taken
to see that this voltage is not greater than the system’s basic insulation
level (BIL). If the fuse maximum design voltage rating does not exceed
140% of the electrical system’s voltage, arc (transient) voltage will not
usually be a problem.

Littelfuse medium voltage fuses are silver-sand, non-expulsion, currentlimiting type. When properly applied, they are designed to carry their
nominal current rating continuously without “fatigue failure.” This means
that the fuse will not age, become brittle, or deteriorate under the most
severe duty cycling.

PEAK

There are two basic types of current-limiting, medium voltage fuses:
general purpose and back-up. General purpose fuses have the ability
to interrupt both large and small short-circuits down to currents which
would cause the fuse to open within one hour. General purpose fuses
are used to provide short-circuit protection for transformers, switchgear,
and similar equipment.

INSTANTANEOUS ARC VOLTAGE
183% OF CYCLEPEAK
RESTORED VOLTAGE

Back-up fuses are designed to only protect against high fault currents
and must be used in series with equipment which provides the circuit’s
required overload and low value short-circuit protection.
Medium Voltage “E” rated fuses are general purpose fuses. Their
mounting dimensions permit them to be installed in a wide variety of
medium voltage switches, in pad-mounted transformers, and other
similar locations. “R” rated MV fuses are specifically designed to
provide short-circuit protection for medium voltage motor controllers
and associated equipment.

Selecting Medium Voltage Fuses
Four factors must be considered when applying MV fuses: voltage
rating, interrupting rating, current rating, and coordination with other
overcurrent protective devices.

Voltage Rating

Fuseology

In common with fuses rated 600 volts and less, MV fuses minimum
voltage ratings must be equal to or greater than the maximum recovery
voltage which the fuse will experience under the worst possible conditions.
Normally, this requires the fuse voltage rating to be greater than the
system’s maximum line-to-line voltage. However, when fusing single-phase
loads which are connected from line-to-neutral on an effectively grounded
four wire wye system, a fuse maximum design voltage only needs to be
greater than the system’s maximum line-to-neutral voltage. When fuses
are selected on this basis, it must be impossible for the fuse to experience
line-to-line voltage. Therefore, if more than one phase is extended beyond
the fuse location, it is best to use fuses with a voltage rating greater than the
maximum line-to-line voltage.

200

Figure 21
However, higher voltage fuses may be used if certain conditions are
met. When tested at nominal voltage rating and rated interrupting
current, Littelfuse MV fuses are designed so that the peak arc voltage
does not exceed three times the fuse nominal voltage. If the electrical
system being protected has a basic insulation level (BIL) greater than
three times the fuse maximum design voltage, the higher voltage fuses
may be used. See the following example:

Given:

System nominal voltage = 4,800 volts
System BIL = 50 kV
Can a POWR-GARD™ 15NLE-80E fuse, rated 14,400 volts
nominal and 15,500 volts max. be used in this system?
Maximum peak voltage produced by this fuse =
3 X 14,400 = 43,200 volts.
43,200 volts is less than the BIL of 50 kV, so the 15NLE-80E fuse
may be used.

Medium Voltage Fuses Used With Lightning Arresters
When MV fuses are in the same circuit with lightning arresters, some
precautions must be taken to insure that the transient voltage spike,
which occurs when the fuse is interrupting a fault, does not cause
lightning arresters to spark over. When checking the BIL of the system,

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Applying Medium Voltage Fuses
ISC = kVA x 1000
1.732 x E

Medium Voltage Fuses Used With Lightning Arresters
(continued from previous page)
lightning arresters are the first things that should be investigated. The
lightning arrester spark-over voltage must be higher than the transient
voltages which can be produced by the MV fuses. If arc voltages
produced by the fuses cause lightning arresters to spark over, a
relatively high current will be shunted into the arresters. However, they
are not designed to interrupt such currents.
If the fuses have a voltage rating higher than the arrester and are installed
on the arrester’s load side, the arrester may spark over when the fuse
is interrupting a large fault. If the system has only distribution class
arresters, there will seldom be a problem because distribution class
arresters have sufficient impedance to prevent large amounts of current
from passing through them. However, intermediate, line, and station type
arresters have low impedance, and if they spark over, sufficient current
may flow in an arrester to damage it severely. Intermediate, line, and
station type arresters should not be applied on the line side or in parallel
with current-limiting MV fuses unless the arresters’ spark over voltages
are greater than the arc voltages the fuses can produce. If the lightning
arresters and the fuses have the same voltage rating, arc voltages will be
within desired limits, and the problem is eliminated.
Another approach is to locate the fuses on the line side of the arresters.
However, in many cases this impossible. Utilities prefer to locate fuses
on the load side of lightning arresters to prevent lightning from damaging
the fuses. In still other cases, fuses may be mounted on the primary
transformer bushings or within pad-mounted transformer enclosures so
that lightning arresters will be on the line side of the fuses.
Machine protection lightning arresters, such as those used to protect
large motors and motor control, have very low spark over values and
may be easily damaged if they are located on the fuses line side.
However, arresters should always be mounted directly on the machine
terminals placing them on the load side of the fuses.

Interrupting Ratings
Maximum rms symmetrical AC component and maximum asymmetrical
current interrupting ratings for Littelfuse MV power fuses are shown in
the medium voltage fuse section of this catalog. MV fuses are tested
with a short-circuit X/R ratio of 25:1 which produces an rms asymmetrical
multiplier of 1.6 times the symmetrical component 1/2 cycle after the fault
occurs. It also produces an instantaneous asymmetrical peak current 2.66
times the rms symmetrical component. The interrupting ratings indicate
the maximum symmetrical and asymmetrical fault current permitted at the
point where the fuse is installed.

ISC = RMS symmetrical short-circuit current
kVA = Three phase short-circuit kVA
E = System line-to-line voltage

Effect of Frequency and Altitude
Interrupting ratings of MV fuses shown in the Product section are
valid for 50 and 60 Hertz systems. For 25 Hertz systems, multiply the
interrupting ratings shown by a factor of 0.74.
The continuous current ratings and interrupting ratings of MV fuses shown
in the Product section are valid up to 3,000 feet. Since the density of air
and its dielectric strength decreases as altitude increases, continuous
current ratings and interrupting ratings are affected at altitudes exceeding
3,000 feet. Table 8 provides altitude correction factors.

Table 8
Altitude Correction Factors per ANSI C37.40-2.3
Altitude Above Sea Level
Feet
4000
6000
8000
10000
12000
14000
16000
18000
20000

Meters
1200
1800
2400
3000
3600
4300
4900
5500
6100

Continuous
Interrupting Rating
Current Multiplier
Multiplier
.99
.98
.97
.96
.95
.93
.92
.91
.90

.98
.92
.86
.80
.75
.70
.65
.61
.56

Continuous Current Ratings
Available current ratings of “E-rated” and “R-rated” MV fuses are
shown in the MV fuse section of this catalog. The current ratings
for MV fuses carry a different meaning than ratings for 600 volt and
below fuses. MV fuses are not intended to provide protection against
overloads or other overcurrents less than two times their continuous
current rating. If MV fuses are exposed to currents only slightly over
their continuous current rating, a large amount of heat is generated
within the fuse. The heat may cause the fuse tube to char and weaken,
and the time-current characteristics may be changed. If circuits can
produce sustained currents that are 100% to 200% of MV fuses current
ratings, other overcurrent devices must be in series with the fuses to
provide overload protection.,

Short-circuit kVA Ratings

When the short-circuit kVA is known, the rms symmetrical AC
component may be determined from the formula:
© 2005 Littelfuse • POWR-GARD™ Products Catalog

MV fuses are designed to carry their rated current without exceeding
the temperature rise permitted by NEMA and ANSI standards. The “E”
and “R” ratings help define the operating characteristics of the fuses:
NEMA Standards for “E-rated” MV power fuses require that fuses rated
100E or less open within 300 seconds (5 minutes) when subjected to
an rms current of 200-240% of the fuse’s continuous current rating.
Fuses with an “E” rating larger than 100E must open within 600
seconds (10 minutes) when subjected to an RMS current of 220-264%
of the fuse continuous current rating.

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Fuseology

It is common to state the short-circuit ratings of MV breakers and other
equipment such as switchgear in terms of short-circuit kVA. It must be
remembered that MV power fuses are not constant kVA devices. For
example, if the voltage is half of the fuse rating, the interrupting capacity
does not double. MV fuse interrupting ratings are given in symmetrical
and asymmetrical amperes. These values must not be exceeded at any
voltage.

201

Fuseology

Fuse Application Guide
Applying Medium Voltage Fuses
1000

NEMA Standards for “R-rated” MV power fuses require that they open
within 15-35 seconds when subjected to an rms current 100 times the
“R” rating.

600
400
300
200

These values establish one point on the fuses time-current curves
and help define the characteristics of E-and R-rated fuses. Since all E
and R-rated fuses must meet these requirements, the time-current
characteristics of E-rated and R-rated fuses of different manufactures
will have a certain similarity, although they are not necessarily identical.

10
8
6
4
3
2

Fuse Maximum
Clearing Curve
Maximum
Transformer
Overload
Current

1
.8
.6
.4
.3
.2

1000

300
400

200

30
40
60
80
100

20

3
4
6
8
10

.1
2

To properly select MV fuses for motor protection, several factors
should be considered. R Rated fuses are only intended for short-circuit
protection and should be applied in conjunction with motor overload
relays. An R Rated fuse does not have an ampere rating and the “R”
rating refers to the opening time of the fuse. R Rated fuses are designed
to safely interrupt any current between their minimum and maximum
interrupting rating. When applying R Rated fuses, it is recommended
to follow the fuse sizing guidelines established by the motor starter
manufacturer.

Fuse Minimum
Melting Curve

1

Motor Protection

100
80
60
40
30
20

TIME IN SECONDS

A long-standing rule of thumb for applying MV fuses states that the
minimum fuse rating should be at least 1.4 times the circuit’s full load
current. This generally insures that MV fuses will not be required to
open overloads. If the nature of the load is such that load currents will
never exceed the rating of the fuse, MV fuses may be rated as close as
1.1 times full load current.

Typical transformer
damage curve for
3- phase faults on
3- phase transformers
and single-phase faults
on 1-phase transformers

CURRENT IN AMPERES
Figure 22

When engineering a system, time-current characteristic curves of the
fuse and overload relay should be compared to insure the overload relay
opens before the fuse during overload conditions. The following table is
provided as a guideline for sizing R Rated fuses.

R-Rated Fuse Sizing Table
For Motors with an
Acceleration of 10 Seconds

For Motors with an
Acceleration of 3 Seconds

Max.Motor FLA

R Rated Fuse

Max.Motor FLA

28A

2R

32A

R Rated Fuse
2R

40A

3R

45A

3R

55A

4R

65A

4R

80A

6R

95A

6R

125A

9R

140A

9R

165A

12R

190A

12R

250A

18R

280A

18R

330A

24R

360A

24R

500A

36R

550A

36R

Transformer Protection
Fuseology

A principle use of MV fuses is to provide primary short-circuit protection
for transformers. When selecting MV fuses to protect transformers,
the following factors must be considered in descending order of
importance:

202

1. As explained above, the fuses voltage and interrupting ratings must
equal or exceed system requirements at the point where fuses will
be applied.
2. The fuse continuous current rating must be large enough to
withstand transformer magnetizing (in-rush) current. (Minimum Fuse
Rating).
3. The fuse continuous current rating must be able to withstand
transformer overloading and emergency operation, and meet NEC
requirements. (Maximum Fuse Rating).
4. Fuses must protect the system on the line side of the fuse from the
effects of short circuits on the load side of the fuses. (Utility System
Coordination).
5. Fuses must coordinate with the transformer secondary protection
where and whenever possible. (Facility System Coordination).
6. Fuses must protect transformer against secondary bolted faults.
7. Where and whenever possible, fuses should protect the transformer
against higher impedance secondary faults.
Transformer magnetizing or inrush current depends on several factors
such as transformer design, residual flux in the core at the instant
the transformer is energized, the point on the voltage wave at which
the switch is closed, and the characteristics of the electrical system
powering the transformer. Power transformers in-rush current
approximates 12 times the transformer full load current, and distribution
transformers 25 to 40 times full load current. The current generally lasts
less than 1/10 second.

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© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Fuse Application Guide
Applying Medium Voltage Fuses
requirement. However, transformers are generally operated at
close to full load current on a continuous basis, and are overloaded
under emergency conditions. A typical example is a double-ended
loadcenter operated with a normally open bus tie. See Figure 23.
Each transformer is rated to carry 150% of the load on its half of the
loadcenter. With loss of service to one transformer, the main switch
for that line is opened, and the bus tie switch is closed shifting all load
to the remaining transformer. The system is operated overloaded until
the other line is back in service. If the outage will continue for a long
period of time, manual load shedding can be used to control transformer
overloading.

Transformers
look like this

Other similar operating schemes also result in transformer overloading.
As a result, MV fuses usually have continuous current ratings larger than
required to withstand transformer in-rush current.
NEC® Article 450 covers transformer installations and establishes
the maximum ratings of transformer overcurrent protective devices.
Regarding medium voltage fuses, Article 450.3 states in part:

Figure 23
To determine the minimum size fuse which will hold the in-rush current,
obtain the in-rush current from the transformer manufacturer and mark
the current on the fuses minimum melting time-current curves at
0.10 second as shown in Figure 22. The minimum fuse rating is the
fuse whose minimum melting curve is just to the right and above the
transformer inrush point.

Overcurrent Protection of transformers shall comply with NEC Article
450.3(A) – Transformers Over 600 Volts, Nominal, and shall be provided
in accordance with Table 9.
NOTE: In this section, the word transformer shall mean a transformer or polyphase bank of
two or more single-phase transformers operating as a single unit.

When the in-rush current is not greater than 12 times transformer
full load current, MV fuses with current ratings that equal or exceed
a transformer’s self-cooled, full load current will usually meet this

Table 9
(Based on NEC Table 450.3(A) – Maximum Rating or Setting of Overcurrent Protection
for Transformers Over 600 Volts (as a Percentage of Transformer-Rated Current))
Primary Protection Over
600 Volts
Location Limitations
Any Location

Supervised
Locations Only (see
Note 3)

Transformer Rated
Impedance
Not more than 6% (see Note 1)
More than 6% but not more than
10% (see Note 1)
Any (see Note 1)
Not more than 6% (see Note 5 for
Secondary Protection)
More than 6% but not more than
10% (see Note 5 for Secondary
Protection)

Circuit Breaker
(see Note 4)
600%

Fuse Rating
300%

Secondary Protection (See Note 2)
Over 600 Volts
Circuit Breaker
Fuse Rating
(see Note 4)
300%
250%

600 Volts or Less
Circuit Breaker or
Fuse Rating
125%

400%

300%

250%

225%

125%

300%

250%

Not Required

Not Required

Not Required

600%

300%

300%

250%

250%

400%

300%

250%

225%

250%

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

Fuseology

Note 1 – If the required fuse rating or breaker setting does not correspond to standard ratings/settings, the next higher rating/setting may be used.
Note 2 – If secondary overcurrent protection is required, no more than six breakers or sets of fuses may be grouped in any one location. When multiple overcurrent devices
are used, the sum of all device ratings shall not exceed the allowed value of any single device. If both breakers and fuses are used, the total of device ratings shall
not exceed that if using only fuses.
Note 3 – A “supervised location” is one where maintenance and supervision conditions ensure that only qualified persons are allowed to monitor and perform installation
service on the transformer.
Note 4 – Electronically actuated fuses set to open at a specific current shall be set and calibrated in accordance with the corresponding settings of the circuit breakers
involved.
Note 5 – Separate secondary protection is not necessary if the transformer is equipped with a coordinated thermal overload protection provided by the manufacturer.

203

Fuseology

Motor Protection Tables

Selection of Class RK5 (FLNR_ID/FLSR_ID & IDSR Series) or POWR-PRO® Class RK1 (LLNRK/LLSRK/LLSRK_ID Series) Fuses Based
on Motor Full Load Amps

Using AC Motor Protection Tables to Select Fuse Ratings
Time-delay RK1 and RK5 fuse ratings selected in accordance with
the following recommendations also meet NEC® requirements for
Motor Branch circuit and Short-Circuit Protection.

Selecting Fuses for Motor Running Protection
Based on Motor Horsepower

1 10

Motor horsepower and motor Full Load Amperes (FLA) shown are
taken from NEC Tables 430.248 through 430.250 covering standard
speed AC motors with normal torque characteristics. Fuse ratings
for motors with special characteristics may need to vary from given
values.
If motor running protection will be provided by the fuses, select
fuse ratings for correct type of motor from Motor Protection Table
Columns headed, “Without Overload Relays.”
If overload relays will provide principal motor running protection,
select fuse ratings for correct type of motor from Motor Protection
Table Columns headed, “Back-up Running Protection” or “With
Overload Relays.” Fuse ratings selected from these columns
coordinate with most UL Class 10 and 20 overload relays which
covers over 90% of motor applications.

Selecting Fuses for Motor Running Protection
Based on Motor Actual Full Load Currents

Fuseology

Better protection is achieved when fuse ratings are based on
motor actual FLA obtained from motor nameplates. Locate motor
nameplate FLA in the column appropriate for the type of motor and
type of protection required. Then select the corresponding ampere
rating from the first column of that line.

204

Time Delay UL
Class RK1 or
RK5 Fuse
Ampere Rating

⁄
⁄
15 100
⁄
2 10
⁄
14
⁄
3 10
⁄
4 10
⁄
12
⁄
6 10
⁄
8 10
⁄
18

1
11⁄ 8
11⁄ 4
14 ⁄ 10
11⁄ 2
1 6 ⁄ 10
1 8 ⁄ 10
2
2 1⁄ 4
2 1⁄ 2
2 8 ⁄ 10
3
3 2 ⁄ 10
31⁄ 2
4
4 1⁄ 2
5
5 6 ⁄ 10
6
6 1⁄ 4
7
71⁄ 2
8
9
10
12
15
17 1⁄ 2
20
25
30
35
40
45
50
60
70
75
80
90
100
110
125
150
175
200
225
250
300
350
400
450
500
600

Motor Running Protection
(Used Without Properly Sized Overload
Relays) Motor Full-Load Amps

Back-up Motor Running Protection
(Used With Properly Sized Overload
Relays) Motor Full-Load Amps

Motor Service
Factor of 1.15 or
Greater or With
Temp. Rise Not
over 40°C.

Motor Service
Factor Less Than
1.15 or with Temp.
Rise Greater
Than 40°C.

Motor Service
Factor of 1.15 or
Greater or With
Temp. Rise Not
Over 40°C.

Motor Service
Factor Less Than
1.15 or with Temp.
Rise Greater
Than 40°C

0.08-0.09
0.10-0.11
0.12-0.15
0.16-0.19
0.20-0.23
0.24-0.30
0.32-0.39
0.40-0.47
0.48-0.60
0.64-0.79
0.80-0.89
0.90-0.99
1.00-1.11
1.12-1.19
1.20-1.27
1.28-1.43
1.44-1.59
1.60-1.79
1.80-1.99
2.00-2.23
2.24-2.39
2.40-2.55
2.56-2.79
2.80-3.19
3.20-3.59
3.60-3.99
4.00-4.47
4.48-4.79
4.80-4.99
5.00-5.59
5.60-5.99
6.00-6.39
6.40-7.19
7.20-7.99
8.00-9.59
9.60-11.99
12.00-13.99
14.00-15.99
16.00-19.99
20.00-23.99
24.00-27.99
28.00-31.99
32.00-35.99
36.00-39.99
40.00-47.99
48.00-55.99
56.00-59.99
60.00-63.99
64.00-71.99
72.00-79.99
80.00-87.99
88.00-99.99
100.00-119.99
120.00-139.99
140.00-159.99
160.00-179.99
180.00-199.99
200.00-239.99
240.00-279.99
280.00-319.99
320.00-359.99
360.00-399.99
400.00-479.99
480.00-600.00

0.09-0.10
0.11-0.125
0.14-0.15
0.18-0.20
0.22-0.25
0.27-0.30
0.35-0.40
0.44-0.50
0.53-0.60
0.70-0.80
0.87-0.97
0.98-1.08
1.09-1.21
1.22-1.30
1.31-1.39
1.40-1.56
1.57-1.73
1.74-1.95
1.96-2.17
2.18-2.43
2.44-2.60
2.61-2.78
2.79-3.04
3.05-3.47
3.48-3.91
3.92-4.34
4.35-4.86
4.87-5.21
5.22-5.43
5.44-6.08
6.09-6.52
6.53-6.95
6.96-7.82
7.83-8.69
8.70-10.00
10.44-12.00
13.05-15.00
15.22-17.39
17.40-20.00
21.74-25.00
26.09-30.00
30.44-34.78
34.79-39.12
39.13-43.47
43.48-50.00
52.17-60.00
60.87-65.21
65.22-69.56
69.57-78.25
78.26-86.95
86.96-95.64
95.65-108.69
108.70-125.00
131.30-150.00
152.17-173.90
173.91-195.64
195.65-217.38
217.39-250.00
260.87-300.00
304.35-347.82
347.83-391.29
391.30-434.77
434.78-500.00
521.74-600.00

0-0.08
0.09-0.10
0.11-0.12
0.13-0.16
0.17-0.20
0.21-0.24
0.25-0.32
0.33-0.40
0.41-0.48
0.49-0.64
0.65-0.80
0.81-0.90
0.91-1.00
1.01-1.12
1.13-1.20
1.21-1.28
1.29-1.44
1.45-1.60
1.61-1.80
1.81-2.00
2.01-2.24
2.25-2.40
2.41-2.56
2.57-2.80
2.81-3.20
3.21-3.60
3.61-4.00
4.01-4.48
4.49-4.80
4.81-5.00
5.01-5.60
5.61-6.00
6.01-6.40
6.41-7.20
7.21-8.00
8.01-9.60
9.61-12.00
12.01-14.00
14.01-16.00
16.01-20.00
20.01-24.00
24.01-28.00
28.01-32.00
32.01-36.00
36.01-40.00
40.01-48.00
48.01-56.00
56.01-60.00
60.01-64.00
64.01-72.00
72.01-80.00
80.01-88.00
88.01-100.00
100.01-120.00
120.01-140.00
140.01-160.00
160.01-180.00
180.01-200.00
200.01-240.00
240.01-280.00
280.01-320.00
320.01-360.00
360.01-400.00
400.01-480.00

0-0.09
0.10-0.11
0.12-0.13
0.14-0.17
0.18-0.22
0.23-0.26
0.27-0.35
0.36-0.43
0.44-0.52
0.53-0.70
0.71-0.87
0.88-0.98
0.99-1.09
1.10-1.22
1.23-1.30
1.31-1.39
1.40-1.57
1.58-1.74
1.75-1.96
1.97-2.17
2.18-2.43
2.44-2.60
2.61-2.78
2.79-3.04
3.05-3.48
3.49-3.91
3.92-4.35
4.36-4.87
4.88-5.22
5.23-5.43
5.44-6.09
6.10-6.52
6.53-6.96
6.97-7.83
7.84-8.70
8.71-10.43
10.44-13.04
13.05- 15.21
15.22-17.39
17.40-21.74
21.75-26.09
26.10-30.43
30.44-37.78
37.79-39.13
39.14-43.48
43.49-52.17
52.18-60.87
60.88-65.22
65.23-69.57
69.58-78.26
78.27-86.96
86.97-95.65
95.66-108.70
108.71-130.43
130.44-152.17
152.18-173.91
173.92-195.62
195.63-217.39
217.40-260.87
260.88-304.35
304.36-347.83
347.84-391.30
391.31-434.78
434.79-521.74

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Motor Protection Tables

Selection of Class RK5 (FLNR_ID/FLSR_ID & IDSR Series) or POWR-PRO® Class RK1 (LLNRK/LLSRK/LLSRK_ID Series) Fuses
Based on Motor Horsepower
Without Overload Relays

Motor HP

16

Full Load
Amps

4.4
5.8
7.2
9.8
13.8
16
20
24

16

⁄
⁄
13
⁄
12
⁄
3 4
⁄
1
12
1⁄
2
3
5
71⁄2
10

2.2
2.9
3.6
4.9
6.9
8
10
12
17
28
40
50

12

⁄
⁄
1
12
1⁄
2
3
5
7 1⁄ 2
10
15
20
25
30
40
50
60
75
100
125
150

2.5
3.7
4.8
6.9
7.8
11
17.5
25.3
32.2
48.3
62.1
78.2
92
120
150
177
221
285
359
414

12

2.2
3.2
4.2
6.0
6.8
9.6
15.2
22
28
42
54
68
80
104
130
154
192
248
312
360
480

14

3 4

⁄
⁄
1
12
1⁄
2
3
5
7 1⁄ 2
10
15
20
25
30
40
50
60
75
100
125
150
200
3 4

Without Overload Relays

120 VOLT 1-PHASE MOTORS (120V CIRCUIT)
5
5
5 6 ⁄ 10
7
6 1⁄4
7 1⁄ 2
9
8
9
12
10
15
15
15
17 1⁄2
20
171⁄ 2
20
25
20
25
30
25
30
230 VOLT 1-PHASE MOTORS (240V CIRCUIT)
2 1⁄ 2
2 1⁄ 2
2 8 ⁄ 10
31⁄ 2
3 2 ⁄ 10
4
4 1⁄2
4
4 1⁄ 2
6 10
6 10
5⁄
5 ⁄
6 1⁄4
8
7 1⁄2
9
10
9
10
12
10
15
15
12
15
12
25
20
17 ⁄
35
30*
35
50
45
50
60
50
70
200 VOLT 3-PHASE MOTORS (208V CIRCUIT)
8 10
3
2⁄
3 2 ⁄ 10
4 1⁄2
4
5
6
5 6 ⁄ 10
6 1⁄ 4
12
8
7⁄
7 1⁄2
9
8
10
12
12
15
20
20
25
30*
25*
35
40
35
45
60
50
70†
75
70
80
90
80
100
110
100*
125
150
125
150
175
150
200
200*
200*
225
250
250
300
350
300
400
400*
400*
450
500
450
600
230 VOLT 3-PHASE MOTORS (240V CIRCUIT)
8 10
12
2⁄
2⁄
2 8 ⁄ 10
4
3 1⁄2
4
5
4 1⁄2
5 6 ⁄ 10
12
14
7⁄
6⁄
7 1⁄2
8
7 1⁄2
9
12
10
12
12
12
17 ⁄
20
17 ⁄
25
25
30
35
30*
35
50
45
60
60*
60*
70
80
75
90
100
90
100
125
110
150
150
150
175
175
175
200
225
200*
250
300
250
350
350
350
400
450
400*
450
600
500
600

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Switch or
Fuse Clip
Rating

5 6 ⁄ 10
7
9
12
17 1⁄ 2
20
25
30

30
30
30
30
30
30
30
30

2 8 ⁄ 10
3 1⁄2
4 1⁄ 2
6
8
10
12
15
20
35
50
60

30
30
30
30
30
30
30
30
30
60
60
60

3
4 1⁄2
6
8
9
15
25
30*
40
60
75
90
110
150
175
225
300
350
450
500

30
30
30
30
30
30
30
60
60
60
100
100
200
200
200
400
400
400
600
600

2 8 ⁄ 10
4
5
7 1⁄ 2
8
12
17 1⁄2
30
35
50
70
80
100
125
150
200
225
300
400
450
600

30
30
30
30
30
30
30
30
60
60
100
100
100
200
200
200
400
400
400
600
600

Motor HP

Full Load
Amps

12

⁄
⁄
1
12
1⁄
2
3
5
7 1⁄2
10
15
20
25
30
40
50
60
75
100
125
150
200

1.1
1.6
2.1
3.0
3.4
4.8
7.6
11
14
21
27
34
40
54
65
77
96
124
156
180
240

12

0.9
1.3
1.7
2.4
2.7
3.9
6.1
9
11
17
22
27
32
41
52
62
77
99
125
144
192

3 4

⁄
⁄
1
12
1⁄
2
3
5
7 1⁄ 2
10
15
20
25
30
40
50
60
75
100
125
150
200
3 4

With Overload Relays

S.F. = Less
S.F. = Less
S.F. = 1.15 Or
S.F. = 1.15 Or
Than 1.15 Or
Than 1.15 Or
More, Temp
More, Temp
Temp Rise
Temp Rise
Rise Not Over
Rise Not Over
More Than
More Than
40°C
40°C
40°C
40°C

460 VOLT 3-PHASE MOTORS (480V CIRCUIT)
14 ⁄ 10
11⁄4
14 ⁄ 10
2
18 ⁄ 10
2
21⁄ 4
28 ⁄ 10
2 1⁄2
12
2 10
3⁄
3⁄
4
4
3 1⁄2
4 1⁄2
6 10
5 ⁄
5
6
9
8
10
12
12
15
171⁄2
15
17 1⁄2
25
20
30
30*
30*
35
40
35
45
50
45
50
60*
60*
70
80
70
90
90
80
100
110
110
125
150
125
175
175
175
200
225
200*
225
300
250
300
575 VOLT 3-PHASE MOTORS (600V CIRCUIT)
11⁄8
1
11⁄ 8
1 6 ⁄ 10
14 ⁄ 10
16 ⁄ 10
2
18 ⁄ 10
2 1⁄ 4
3
2 1⁄2
3
3 2 ⁄ 10
28 ⁄ 10
3 1⁄ 2
12
4
5
4⁄
7 1⁄2
7
8
10
10
12
12
12
15
25
20
17 1⁄2
25
25
30
30*
30*
35
40
35
40
50
45
60
60
60
70†
75
70
80
90
80
100
110
110
125
150
125
175
175
150
200
225
200*
250

Switch or
Fuse Clip
Rating

14 ⁄ 10
2
2 1⁄2
3 1⁄2
4
5 6 ⁄ 10
9
15
17 1⁄2
25
35
40
50
60*
75
90
125
150
200
225
300

30
30
30
30
30
30
30
30
30
30
60
60
60
100
100
100
200
200
200
400
400

11⁄ 8
16 ⁄ 10
2
3
2 10
3 ⁄
41⁄ 2
7 1⁄2
12
15
20
30
35
40
50
60
75
90
125
150
175
225

30
30
30
30
30
30
30
30
30
30
30
60
60
60
60
100
100
200
200
200
400

Fuseology

⁄
⁄
13
⁄
12
⁄
3 4
⁄
1
12
1⁄
2
14

With Overload Relays

S.F. = Less
S.F. = Less
S.F. = 1.15 Or
S.F. = 1.15 Or
Than 1.15 Or
Than 1.15 Or
More, Temp
More, Temp
Temp Rise
Temp Rise
Rise Not Over
Rise Not Over
More Than
More Than
40°C
40°C
40°C
40°C

NOTES
S.F. = Motor Service Factor
* Fuse Reducers Required
† 100 Amp Switch Required

www.littelfuse.com

205

Fuseology

Motor Protection Tables
Selection of POWR-PRO® Class J (JTD_ID/JTD Series) Fuses
Based on Motor Full Load Amps

Motor F.L.A.

JTD_ID/JTD
Ampere Rating
8

0.00 – 0.60
0.61 – 0.80
0.81 – 1.00
1.01 – 1.20
1.21 – 1.65
1.66 – 2.00
2.01 – 2.40
2.41 – 3.30
3.31 – 4.10
4.11 – 4.90
4.91 – 6.40
6.41 – 8.00
8.01 – 9.80
9.81 – 12.0

⁄ 10

1
11⁄4
1 1⁄2
2
2 1⁄2
3
4
5
6
8
10
12
15

Motor F.L.A.

JTD_ID/JTD
Ampere Rating

Motor F.L.A.

JTD_ID/JTD
Ampere Rating

12.1 – 14.5
14.6 – 17.0
17.1 – 21.0
21.1 – 25.0
25.1 – 28.5
28.6 – 34.0
34.1 – 37.0
37.1 – 41.0
41.1 – 48.0
48.1 – 52.0
52.1 – 59.0
59.1 – 66.0
66.1 – 76.0

17 1 /2
20
25
30
35
40
45
50
60
70
80
90
100

76.1 – 84.0
84.1 – 90.0
90.1 – 102
103 – 125
126 – 144
145 – 162
163 – 180
181 – 204
205 – 240
241 – 288
289 – 312
313 – 360
361 – 432

110
125
150
175
200
225
250
300
350
400
450
500
600

NOTE: For severe motor starting conditions, fuses may be sized up to 225% motor F.L.A. (See NEC Article 430.52 for Exceptions)

Selection of CCMR Time-Delay Fuses Based on Motor Full Load Amps
Motor Full Load Current (F.L.A.)
For Motors With An Acceleration
Time Of 2 Seconds Or Less

For Motors With An Acceleration
Time Of 5 Seconds Or Less

For Motors With An Acceleration
Time Of 8 Seconds Or Less

Min. F.L.A. (1)

Max F.L.A. (3)

Min. F.L.A. (1)

Max F.L.A. (3)

Min F.L.A. (2)

Max F.L.A. (3)

0.2
0.3
0.4
0.5
0.6
0.8
0.9
1.1
1.2
1.5
1.8
2.1
2.3
2.6
2.9
3.3
3.5
3.6
4.1
4.3
4.6
5.2
5.8
6.9
8.9
11.5
14.3
20.7
23.7
26.6
30.0
35.5

0.2
0.4
0.6
0.7
1.0
1.1
1.3
1.4
2.1
2.6
3.0
3.4
3.9
4.3
4.8
5.2
5.4
5.7
5.8
6.2
6.9
7.7
8.9
10.0
13.5
15.8
17.8
23.3
26.7
30.0
33.3
40.0

0.2
0.3
0.4
0.5
0.6
0.8
0.9
1.1
1.2
1.5
1.8
2.1
2.3
2.6
2.9
3.3
3.5
3.6
4.1
4.3
4.6
5.2
5.8
6.9
8.9
11.2 (2)
13.4 (2)
16.1
18.4
20.7
23.0
27.6

0.2
0.4
0.5
0.6
0.9
1.0
1.1
1.2
2.1
2.6
3.0
3.2
3.3
3.4
3.7
4.0
4.1
4.2
4.3
4.6
5.2
5.8
6.6
7.7
10.0
11.8
13.4
17.9
20.5
23.1
25.6
30.1

0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.2
1.4
1.6
1.8
2.0
2.3
2.5
2.7
2.8
3.2
3.4
3.6
4.0
4.5
5.4
6.7
6.8
9.0
10.0
15.6
17.8
20.0
22.3
26.7

0.2
0.3
0.5
0.6
0.8
0.9
1.0
1.1
1.8
2.3
2.6
2.8
2.8
2.8
3.1
3.4
3.5
3.7
3.8
4.2
4.5
4.9
5.5
6.7
9.0
11.0
15.0
15.9
18.2
20.4
22.7
27.3

CCMR
Ampere Rating
3 10

⁄
⁄
8 10
⁄
12

1
11⁄4
1 1⁄2
18 ⁄ 10
2
21⁄2
3
3 1⁄2
4
4 1⁄2
5
5 6 ⁄ 10
6
6 1⁄4
7
71⁄2
8
9
10
12
15
20
25
30
35
40
45
50
60

Fuseology

1 Based on NEC requirement limiting the rating of time-delay fuses to 175% of motor F.L.A., or next NOTE: These values were calculated for motors with Locked Rotor
higher rating.
Current (LRA), not exceeding the following values:
2 Based on NEC exception permitting fuse rating to be increased, but not to exceed, 225% motor
Motor F.L.A.
*LRA
F.L.A., however per NEC Article 430.52 Class CC (0-30) fuses can now be sized up to 300% of
0.00 – 1.00
850%
motor F.L.A.
1.01 – 2.00
750%
3 Based on Littelfuse CCMR time-delay characteristics.
2.01 – 10.0
10.1 – 17.8

650%
600%

*If motor LRA varies from these values, contact Littelfuse.

206

www.littelfuse.com

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Fuseology

Condensed Cross Reference
Power/Electronic Fuses
This cross reference covers most popular fuses for which there is a similar Littelfuse standard item. Furnished for your convenience, it is meant to
serve as a guide only for product selection. We suggest you check all applicable specifications before making substitutions. For special applications,
consult the factory.
For more complete information, and for fuse block and medium voltage fuse cross referencing, send for Cross Reference Booklet EC501
or call 1-800-TEC-FUSE (1-800-832-3873).

Competition

Littelfuse
NLN
NLS
NLN
NLS
251
L15S
L15S
L15S
L25S
L50S
L60S
KLK
L70S
L15S
L25S (AC only)
LLNRK
KLNR
JLLN
KLPC
KLLU or KLPC
KLPC or KLLU
JLS
L50S
L60S
LLSRK_ID
KLSR
JLLS
L70S
CCK
SLC
AGA
312
BLN
AGW
JTD_ID
CNL
CNN
ATO (257)
FLNR_ID (note 3)
CCMR
KLK
KLKR
FLQ
KLDR
481
252
BLF
BLN
BLS
2CO
2CC
JLS
JLS
KLPC or KLLU

Competition
CLL
CLU
CM
CMF
CNM
CNQ
CRN-R
CRS-R
CSF13X
CSF25X
CSF50P
CSF60C
CSF60X
CSF70P
CTN-R
CTS-R
EBS
ECNR
ECSR
ELN
ELS
ERN
ERS
FNA
FNB
FNM
FNQ
FNQ-R
FRN-R
FRS-R
FWA (note 2)
FWH (note 2)
FWP (note 1)
FWX (note 1)
GDA
GDB
GDC
GDL
GEB
GEBN
GFA
GFN
GGC
GGM
GLR
GMT
HCLR
HCTR
HEB
HET
HLR
J
JDL
JFL

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Littelfuse
KLLU or KLPC
KLLU or KLPC
BLF
BLN
FLM
FLQ
FLNR_ID (note 3)
FLSR_ID
L15S
L25S (AC only)
L50S
KLC (AC only)
L60S (AC only)
L70S
KLNR
KLSR
BLS
FLNR_ID (note 3)
FLSR_ID
LKN
LKS
RLN
RLS
FLA
235
FLM
FLQ
KLDR
FLNR_ID (note 3)
FLSR_ID
L15S
L50S
L70S
L25S
216
217
218
313
LEB
LET
251
FLA
312
235
LGR
481
KLKR
KLDR
LEB
LET
LHR
JLS
JTD_ID
JLS

Competition

Littelfuse

Competition

Littelfuse

JTD_ID
KLNR
JHC
NCLR
JLLN
NLN
JJN
NON
JLLS
NLS
JJS
NOS
JLS
NLN
JKS
NRN
L15S
NLKP
KAA
NRN (15-60A)
L25S
NLS
KAB
NRS
KLC
NLN
KAC
OT
L50S
BLF or BLN
KBH
OTM
KLKD
NLN
KLM
OTN
CCMR
NLS
KLMR
OTS
KLLU or KLPC
RLN
KLU
REN
KLNR
RLS
KN
RES
NLN
RLN
KON
RF
NLS
L15S
KOS
RFA
KLPC
KLC
KRPC (SP)
RFC
KLPC
L70S (700V)
KRPC-L
RFL (750V)
KLSR
RLN
KS
RFN (Ferraz)
KLK
RLS
KTK
RFS (Ferraz)
KLKR
L50S
KTKR
RFV
KLNR
KLNR
KTNR
RHN
KLSR
KLSR
KTSR
RHS
KLPC
LKN
KTU
RLN (Ferraz)
KLLU or KLPC
LKS
L
RLS (Ferraz)
KLPC or KLLU
SOO
LCL
S
KLPC or KLLU
SAO
LCU
SA
LLNRK
SLC
LENRK
SC
LLSRK_ID
KLSR
LESRK
SCLR
LKN
SLC
LKN
SEC
LKS
L15S
LKS
SF13X
KLLU
L25S
LKU
SF25X
LLNRK
L50S
LONRK
SF50P
LLSRK_ID
L60S
LOSRK
SF60X
CCMR
L70S
LPCC
SF70P
JTD_ID
SFE
LPJ (SP)
SFE
LLNRK
SLO
LPNRK (SP)
SL
LLSRK_ID
TOO
LPSRK (SP)
T
KLK
JLLN
MCL
TJN
326
JLLS
MDA
TJS
313
TLO
MDL
TL
313
FLNR_ID (note 3)
MDQ
TR
315
FLM
MDV
TRM
313
FLNR_ID (note 3)
MDX
TRN-R
FLM
FLSR_ID
MEN
TRS
FLQ
FLSR_ID
MEQ
TRS-R
FLA
L25S
MID
XL25X
BLN
L50S (note 1)
MOF
XL50F
BLF
L70S (note 1)
MOL
XL70F
312
MTH
1) Check specific mounting dimensions before substituting.
2) Check fuse characteristics and mounting dimensions for specific application before substituting.
3) For 1/10 - 30 amperes, order non-indicating FLNR series fuses.
Remember a fuse may be used in circuits where the fuse’s voltage rating is equal to or greater than
the circuit voltage, unless otherwise stated on the fuse. For example, the FLSR_ID indicating fuse
has a voltage rating of 75-600 volts. This fuse can be used on 600 volts, 480 volts, 250 volts, 125
volts, or 75 volts. Never use a fuse in a circuit having higher rated voltage than the fuse.

www.littelfuse.com

Fuseology

10KOTN
10KOTS
50KOTN
50KOTS
A
A013F
A015F
A015R
A025F
A050F
A060F
A060URL
A070F
A13X
A25X
A2D-R
A2K-R
A3T
A4BQ
A4BT
A4BY
A4J
A50P (type 1 & 4)
A60X
A6D-R
A6K-R
A6T
A70P
ACK
AG
AGA
AGC
AGU (1-30A)
AGW
AJT
ANL
ANN
ATC
AT-DE
ATDR
ATM
ATMR
ATQ
ATQR
AX
AXRAD
BAF
BAN
BBS
CGL (2-100A)
CGL (125-600A)
CJ
CJS
CLF

207

Fuseology

Alphanumeric Index of Catalog Numbers
Catalog Number

Page Number Catalog Number

Page Number Catalog Number

Page Number Catalog Number

Page Number

Arc-Flash
ATO series
BLF series
BLN series
BLS series
Box Cover Units
CablePro®
CBO series
CCK series
CCL series
CCMR series
Class CC
Class CD
Class G
Class H
Class J
Class K5
Class L

177
60
51
51
52
158-159
62
107
107
107
20-21, 45-47
20-21, 45-47
20-21, 45-47
44
38
17-19, 39-40
36-37
8-10, 23-24,
26-28
11-16, 34-35
22, 29-33
41-43
107
107
128, 168
168
166-167
177-181
137-144
182-183
55-59
69-74
161-169
127
160
52
50
33
29-32
51
33
29-32
53
126
172-206
157
131
22
135-136
145-150
62
41-43
41-43
39-40
17-19
85, 87
45-47
50
50

45-47
26-28
34-35
8-10
53
34-35
85-86
77
85-86
124
85-86
125-126
125-126
125-126
85, 87
85, 87
88-89
90-91
92-93
94
95
96-98
99-100
101
102-104
102, 105-106
131
137-144
23-24
145-150
145-150
145-150
145-150
145-150
108
156
133
156
124
5, 162
109
75
112-116
130
112-116
130
133
108
117-119
130
38
38
14-16
14-16
11-13
109
53
131
138

154-155
152-153
152-153
152-153
152-153
152-153
128
163
129
128
112-116
112-116
157
137-144
134
158-159
160
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
158-159
120-123
120-123
81-82
174
60
63-75
61
131
61
60
173
6
166-167
164-165
36-37
36-37
36-37
170-174
48
74
38
38
65-68
48
83-106
60

44
48
48
127
137-144
170-174
76-80
78
48
79
173
48
129
129
147
160
57
57
57
57
58
58
56
56
58
58
59
59
see ATO
59
59
59
59
see MIN
see MAX
169
169
169
55
55
56
55
55
55
55
55
55
56
59
80
62
61
132
132
80
75

Fuseology

Class RK1
Class RK5
Class T
CNL series
CNN series
CYHP001
Cylindrical Fuses
Diazed Fuses
Definitions
Distribution Blocks
Electrical Safety
Electronic Fuses
E-Rated Fuses
European Fuses
FBDIN1
FDR001PG
FLA series
FLM series
FLNR series
FLNR_ID series
FLQ series
FLSR series
FLSR_ID series
FLU series
Fuse Blocks
Fuseology
Fuse Reducers
GFP
IDSR series
ILS series
Inline Fuseholders
JCASE series
JLLN series
JLLS series
JLS series
JTD_ID series
KLC series
KLDR series
KLK series
KLKD series

208

KLKR series
KLLU series
KLNR series
KLPC series
KLQ series
KLSR series
L15S series
L17T series
L25S series
L30030G series
L50S series
L60030C series
L60030M series
L60060C series
L60S series
L70S series
LA15QS
LA30QS
LA50QS
LA60QS
LA60X
LA70QS
LA100P
LA120X
LA070URD
LA130URD
LCC series
LD series
LDC series
LEB series
LEC series
LET series
LEX series
LEY series
LFCL series
LFDS series
LFFB001
LFFS030CC
LG300 series
LgD series
LGR series
Live Parts
LH250 series
LH250-PC series
LH600 series
LH600-PC series
LHFB
LHR series
LJ600 series
LJ600-PC series
LKN series
LKS series
LLNRK series
LLSRK series
LLSRK_ID series
LMF series
LNNB
LPFP
LPBC series

LPMP series
LPS1
LPS2
LPS3
LPS4
LPS6
LPSC series
LPSG series
LPSJ series
LPSM series
LR250 series
LR600 series
LRU series
LS series
LSCR series
LSCY
LSFC
LSKA
LSOU
LSOW
LSOX
LSOY
LSOY-B
LSRU
LSRW
LSRX
LSRY
LSSU
LSSW
LSSX
LSSY-L
LSSY-RL
LSTY
LT300 series
LT600 series
LTFD series
LVSP series
MAX series
Medium Voltage
MEGA series
MFP
MIDI series
MIN series
MOV
MROplus
Neozed Fuses
NH Fuse Links
NLKP series
NLN series
NLS series
Overvoltage
Plug Fuses
PT Fuses
RLN series
RLS series
R-Rated Fuses
SAO series
Semiconductor Fuses
SFE series

www.littelfuse.com

SLC series
SLO series
SOO series
SPL001
Splicer Blocks
Suppression
Telecom Fuses
TLN series
TLO series
TLS series
TMOV
TOO series
US3J series
US6J series
WPB series
094324PG
215 series
216 series
217 series
218 series
224 series
225 series
229 series
230 series
235 series
239 series
251 series
252 series
257 series
272 series
273 series
278 series
279 series
297 series
299 series
2CC series
2CM series
2CO series
312 series
313 series
313_ID series
314 series
315 series
318 series
324 series
325 series
326 series
334 series
473 series
481 series
496 series
498 series
571 series
572 series
70 series
700 series

© 2005 Littelfuse • POWR-GARD™ Products Catalog

Littelfuse®
POWR-GARD™ Products
Littelfuse provides our customers with a comprehensive range of
electrical products used to protect:
• Industrial motors and drives
• Pumps and compressors
• Power distribution circuits and wiring devices
• Medium voltage power distribution grids
• Lighting circuits

Littelfuse®
POWR-GARD™ Services Designed to Add Value
At Littelfuse we are committed to partnering with our
customers. That means not only providing the right circuit
protection solution, but also offering services that will
continually add value to your initiatives:

TM

MROplusTM : (Material Reduction
Opportunity plus, the industry’s
best indicating fuse line)

Littelfuse
Safety Program
Did you know that 97% of all electricians have been shocked
or injured on the job? To help you increase safety in your facility
Littelfuse offers the following:
• Current-Limiting Fuses and Accessories
• Electrical Safety Literature and Arc-Flash Calculators

Improve performance while lowering operational costs – for free.

• Electrical Safety Video

When you use our MROplus program, our technical service
professionals will run a free comprehensive fuse analysis,
evaluating your current purchases and complete fuse inventory,
including identification of duplicate and obsolete fuses. After
the analysis you will receive a detailed report with streamlining
recommendations, annual cost savings estimates and ways to
improve safety and decrease downtime.

• Training Seminars and Presentations
• MROplus Fuse Inventory Analysis
• Technical Support and Engineering Services
Littelfuse safety experts are here to help you stay safe on the job.
We can assist you in developing an Electrical Safety Program in
your own facility.

Techline

24-Hour Emergency Fuse Service

800-TEC-FUSE ( 800-832-3873 )

847-824-1188

Our technical hotline is available 8:00 a.m. – 4:30 p.m. CST.
The Littelfuse technical specialists are there to answer questions,
assist in cross-references and provide application expertise.

Our Emergency Fuse Service is available 24 hours a day, seven
days a week — even on holidays. Just call our emergency fuse
service number and one of our trained service agents will be
happy to help you.
When looking for the right solutions, companies around the
world count on the expertise of Littelfuse – the global leader
in circuit protection.

© 2005 Littelfuse • POWR-GARD™ Products Catalog

www.littelfuse.com

World Headquarters
Littelfuse, Inc.
800 E. Northwest Highway
Des Plaines, IL 60016 USA
www.littelfuse.com

International Sales,
Distribution and
Engineering Facilities:
North America
• Des Plaines, Illinois USA
and Irving, Texas USA
Technical Assistance
Phone: 800 TEC FUSE
847 824 1188
Fax: 217 268 5094
Europe
• Dünsen, Germany
Phone: +49 4244 8190
Fax: +49 4244 819 139
• Eltville, Germany
Phone: +49 6129 460
Fax: +49 6129 46222
• Kaposvár, Hungary
Phone: +36 8250 8335
Fax: +36 8241 7529
• Munich, Germany
Phone: +49 8955 27660
Fax: +49 8955 276 699
• Utrecht, The Netherlands
Phone: +31 30 299 9900
Fax: +31 30 299 9800
• Swindon, United Kingdom
Phone: +44 179 372 0400
Fax: +44 179 372 0401

Asia/Pacific
• Hong Kong, China
Phone: +852 2810 5099
Fax: +852 2810 5500
• Beijing, China
Phone: +86 10 8454 9408
Fax: +86 10 8454 9409
• Shanghai, China
Phone: +86 21 5383 8016
Fax: +86 21 5383 7476
• Shenzhen, China
Phone: +86 755 8207 0760
Fax: +86 755 8207 0759
• Singapore
Phone: +65 6885 9111
Fax: +65 6885 9113
• Shin-Yokohama, Japan
Phone: +81 45 478 1088
Fax: +81 45 478 1089
• Seoul, Korea
Phone: +82 2 6000 8600
Fax: +82 2 6000 8655
• Taipei, Taiwan
Phone: +886 2 8751 1234
Fax: +886 2 8751 1177

Research and
Manufacturing Facilities:
• Arcola, Illinois USA
• Des Plaines, Illinois USA
• Dongguan, China
• Dundalk, Ireland
• Dünsen, Germany
• Eltville, Germany
• Grenchen, Switzerland
• Irving, Texas USA
• Lipa City, Philippines
• Matamoros, Mexico
• Piedras Negras, Mexico
• Siemianowice Slaskie, Poland
• Suzhou, China
• Swindon, United Kingdom
• Uebigau, Germany
• Witten, Germany
Other Catalogs Available
• Electronic Designer’s Guide
• Teccor® Power Thyristor Databook
• Automotive OEM Catalog
• Automotive Aftermarket Catalog

Central and South America
• São Paulo, Brasil
Phone: +55 113 835 3780
Fax: +55 113 645 0612

FORM NO. PF101-11
© October 2005, Littelfuse Inc. Printed in U.S.A.
Specifications descriptions and illustrative material in this literature are as accurate as known at the time
of publication, but are subject to changes without notice. Visit www.littelfuse.com for the most up-to-date
technical information. Littelfuse reserves the right to change the design or construction of any product
without notice.

2

2



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