KLLU Series - 600 V - UL Class L Time-Delay Fuses

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KLLU series UL Listed, time-delay, Class L are quality fuses in every sense of the word. They were 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 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 manufacturer’s literature for recommended fuse rating.


  • 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:

  • Current limiting — Reduces short circuit damage to systems and equipment.
  • Reduced downtime
  • Ten second minimum time delay at 500 percent of rating 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 short circuits 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…meets present and future system requirements.
  • KLLU fuse time-current characteristics closely match typical time-current 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.

Access specifications, certifications, check availability and order parts below

Catalog #Amps (A)VAC (V)VDC (V)Interrupting RatingOpeningSizeStockSamplesCompare
KLLU601601600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU650650600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU700700600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU750750600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU800800600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU900900600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU10001000600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU12001200600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU13501350600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU14001400600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU15001500600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU16001600600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU18001800600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU20002000600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU25002500600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU30003000600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU35003500600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
KLLU40004000600300200000A@600VACSlo-Blo/Time Lag (T)/Time DelayBolt-InCheckOrder
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