Rev: 1-A-052022

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CLASS RK1 – LLNRK • LLSRK • LLSRK_ID SERIES FUSES

Description

RK1 fuses are extremely current-limiting fuses meaning they

greatly reduce or eliminate damage to circuits and equipment under

short-circuit conditions. Replacing existing Class H, K and RK5 fuses

with RK1 fuses is one of the easiest ways to immediately improve

the protection of plant workers and equipment.

Applications

• All general purpose circuits

• Motors

• Transformers

• Safety upgrades

Features/Benefits

• POWR-PRO Performance

• Indication available

• Dual-element design

• Extremely Current-Limiting

• IEC Type 2 “No Damage” protection to IEC and NEMA

type motor starters

• Indicating and DIN mount fuse holders available

Specifications

Voltage Ratings

600 Vac/300 Vdc (LLSRK/LLSRK_ID)

250 Vac/125 Vdc (LLNRK)

Interrupting Ratings

AC: 200 kA rms symmetrical

300 kA rms symmetrical

(Littelfuse self-certified)

DC: 20 kA

Ampere Range

1/10 – 600 A

Approvals

AC: Standard 248-12, Class RK1

UL Listed (File: E81895)

CSA Certified (File: LR29862)

DC: Littelfuse self-certified

Federal Specification WF-1814

(QPL- W-F-1814)

AMPERE RATINGS

1

1

25

80

250

15

3

7

30

90

300

2

8

35

100

350

1

9

40

110

400

3

4

10

45

125

450

4

12

50

150

500

1

2

5

15

60

175

600

6

70

200

8

6

20

75*

225

*Ampere rating only available for the 600 V.

Web Resources

Download TC Curves, CAD drawings and other technical

information: littelfuse.com/llsrk

littelfuse.com/llnrk

Recommended Fuse Holders

LFR60 Series • LFR25 Series

1,000

10,000

100,000

600A -

400A -

200A -

100A -

60A -

30A -

12A -

5A -

3.5A -

10

100

10

100

1,000

10,000

100,000

AVAILABLE FAULT CURRENT

SYMMETRICAL R.M.S. AMPERES

BASIS FOR DATA:

TEST VOLTAGE: 600V

TIME CONSTANT/POWER FACTOR:

FUSE CATALOG NUMBER:

DRAWN BY:

DATE:

REVISION:

DRAWING NO.:

SHEET

PEAK LET‐THRU CHARACTERISTIC CURVES

LITTELFUSE, INC.

CHICAGO, IL. USA

LLL

03/14/2016

A

2 OF 6

FCC05-LSRK

LLSRK & LLSRKID 3.5A - 600A

- DATA GENERATED IN EXCEL -

Peak Let-Thru Curve (600 V)

Note: For more information, see Peak Let-Thru Table

Dimensions

Please refer to the Class R dimensions page 3.

Ordering Information

TYPE

SERIES

AMP

CATALOG

NUMBER

ORDERING

NUMBER

INDICATING

LLSRK_ID

60

LLSRK060ID

LSRK060.TXID

NON-INDICATING

LLSRK

60

LLSRK060

LSRK060.T

600 V

250 V

TYPE

SERIES

AMP

CATALOG

NUMBER

ORDERING

NUMBER

NON-INDICATING

LLNRK

80

LLNRK080

LNRK080.V

LLSRK & LLSRKID

QPL