Littelfuse LLNRK Series POWR-PRO Dual-Element Time-Delay Fuse

Littelfuse LLNRK Series POWR-PRO Dual-Element Time-Delay Fuse

The Littelfuse LLNRK Series POWR-PRO fuses are dual-element, time-delay fuses engineered to deliver overload and short-circuit protection for service entrance, main, feeder, and general-purpose branch circuits rated up to 600 amperes, and are available in 100A and 300A models to fit a range of Class H fuse block applications. Rated 250VAC / 125VDC, these fuses are designed as a direct upgrade for existing Class H fuse blocks that currently house lower interrupting-rating Class H one-time or renewable fuses, giving facilities a higher level of protection without replacing the fuse block. Their true dual-element, current-limiting construction is built to handle demanding, high-inrush applications while resisting nuisance opening from routine power surges.

Key Features

• Model Options: Available in 100A and 300A ratings within the LLNRK Series to match the load and protection needs of the application.
• Class H Fuse Block Compatible: Installs directly into existing Class H fuse blocks, upgrading systems that use lower interrupting-rating Class H one-time or renewable fuses.
• Electrical Ratings: Rated 250VAC and 125VDC, with an interrupting rating of 20,000A@125VDC for reliable performance under fault conditions.
• 300kA Interrupting Rating: Littelfuse self-certifies the LLNRK Series to 300,000 amperes as standard, for higher available short-circuit currents.
• True Dual-Element Construction: A separate, non-fatiguing, thermally-reversible spring-loaded thermal overload element withstands repeated surges within the rated time delay without needless opening, cutting nuisance downtime.
• Extremely Current Limiting: Stops damaging short circuits faster than a mechanical device, reducing equipment damage.
• Reduced System Costs: Current-limiting design often permits less costly downstream equipment, while low resistance reduces power consumption.
• Time-Delay Opening: Slo-Blo / Time Lag (T) / Time Delay opening characteristic suited to motors, transformers, and other high-inrush loads.
• Industrial Cartridge Package: Supplied in an industrial cartridge package size for straightforward installation in compatible fuse blocks and holders.

Certifications & Compliance

• UL Listed (UL File JDDZ E81895)
• CSA Certified (CSA 1422-02 029862)

Technical Specifications

• Voltage Rating: 250VAC/125VDC
• Configuration: Time-Delay (Slo-Blo)
• Standards: CSA

Typical Applications

• Solenoids
• Fluorescent Lighting Circuits
• All General-Purpose Circuits
• Motors and Transformers
• System Components with High In-Rush Currents
• Service Entrance, Main, Feeder, and Branch Circuit Protection up to 600A

Why Littelfuse?

Littelfuse backs the LLNRK POWR-PRO Series with true dual-element, current-limiting construction, a self-certified 300kA interrupting rating, and UL and CSA certification—a dependable, code-compliant fuse lineup spanning 100A to 300A for upgrading Class H fuse blocks.