KLNR/KLSR Class RK1
250/600 VAC • Fast Acting • 1 – 600 Amperes
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.
• 200,000 A.I.R. — Reliable interruption of all overcurrents up to
• 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
Longer Equipment Life
• Current-limiting design reduces damage to equipment caused by
heating and magnetic effects of short-circuit currents.
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
Easy To Use
• 200,000 A.I.R. rating minimizes need for short-circuit calculations.
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.
• Refer to FLNR_ID for KLNR dimensions and FLSR_ID for KLSR
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 aperes rs syetrical
DC: 20,000 aperes
1 – 600 aperes.
AC: Standard 248-12, Class RK1
Exaple part nuber (series & aperage): KLNR 200
UL Listed (File No: E81895)
CSA Certified (File No: LR29862)
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 inforation.
DC: Littelfuse self-certified