Littelfuse FLNR Series Class RK5 Dual-Element Time-Delay Fuse

Littelfuse FLNR Series Class RK5 Dual-Element Time-Delay Fuse

The Littelfuse FLNR Series is a UL Class RK5 dual-element time-delay fuse line, one of the most widely used fuse classes in the industry and a superior choice for protecting circuits that contain motors. Rated 125VDC and 250VAC with an interrupting rating of 20000A@125VDC, these Industrial Cartridge fuses deliver reliable interruption of overcurrents up to 200,000 amperes (A.I.R.), providing faster-acting short-circuit protection than any non-current-limiting mechanical protective device. Available across FLNR series models — FLNR.500, FLNR.600, FLNR.800, FLNR100, FLNR125, FLNR150, and FLNR300 — to match specific circuit amperage requirements, the series is UL Listed and CSA Certified for use in motor control centers, distribution panelboards, and industrial control panels, and is also well suited to all general-purpose circuits.

Key Features

• Time-Delay Opening: Slo-Blo/Time Lag (T)/Time Delay opening characteristic rides through motor inrush current and temporary overloads without nuisance opening.
• High Interrupting Rating: Interrupting rating of 20000A@125VDC with reliable interruption of overcurrents up to 200,000 amperes (A.I.R.), delivering faster-acting short-circuit protection than any non-current-limiting mechanical protective device.
• Dual Voltage Rating: Rated 125VDC and 250VAC for flexible use across DC and AC control and distribution circuits.
• UL Class RK5 Dual-Element Construction: Automated, precision-manufactured and assembled parts ensure accurate, consistent response to overloads and short circuits.
• Industrial Cartridge Package: Sized to fit standard industrial cartridge fuse holders and clips for straightforward replacement.
• Motor Circuit Protection: Purpose-built for motor control center mains, motor branch circuits, and individual fused combination motor controllers.
• Broad Circuit Coverage: Suitable for service entrance switches, switchboard main and feeder switches, and all general-purpose circuits.
• Series Range: Offered across FLNR.500, FLNR.600, FLNR.800, FLNR100, FLNR125, FLNR150, and FLNR300 models to cover a range of circuit amperage needs.

Certifications & Compliance

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

Technical Specifications

• Voltage Rating: 125VDC / 250VAC
• Standards: CSA

Typical Applications

• Motor Control Center Mains and Motor Branch Circuits
• Individual Fused Combination Motor Controllers
• Service Entrance Switches
• Distribution Panelboards and Loadcenters
• Industrial Control Panels
• Switchboard Main and Feeder Switches

Why Littelfuse?

Littelfuse FLNR series fuses combine UL Class RK5 dual-element construction with automated, precision-manufactured assembly for consistent, code-compliant overcurrent protection. With a 200,000 ampere interrupting rating plus UL Listed and CSA Certified performance, the FLNR series gives electrical professionals a dependable, time-delay fuse rated 125VDC/250VAC for demanding motor circuits, panelboards, and general-purpose distribution work.