Littelfuse FLNR_ID Indicator Series Class RK5 Time-Delay Fuse, 250VAC/125VDC

Littelfuse FLNR_ID Indicator Series Class RK5 Time-Delay Fuse, 250VAC/125VDC

The Littelfuse FLNR_ID Indicator Series is a Class RK5 dual-element time-delay fuse family rated 250VAC / 125VDC with an interrupting rating of 300,000A@250VDC, available in 40A, 45A, 60A, and 125A ratings to cover a wide range of branch-circuit and equipment protection needs. Each fuse uses a patented solid-state design to deliver visual blown-fuse indication at a glance, helping electricians and maintenance teams pinpoint an open fuse without testing. The Slo-Blo/Time Lag (T) time-delay characteristic reduces nuisance opening while maintaining reliable overload and short-circuit protection for industrial and commercial electrical systems, from motor controllers to distribution panelboards.

Key Features

• Amp Rating Range: Available in 40A, 45A, 60A, and 125A ratings for branch-circuit and equipment protection.
• Voltage Rating: 250VAC / 125VDC for use across AC and DC industrial circuits.
• Interrupting Rating: 300,000A@250VDC for high fault-current withstand.
• Time-Delay Opening: Slo-Blo/Time Lag (T)/Time Delay characteristic reduces nuisance opening and extends fuse life.
• Visual Blown-Fuse Indication: The Indicator window shows an open fuse at a glance, with power on or off, so no fuse testing or second-guessing is required.
• Dual-Element Solid-State Design: Patented construction delivers maximum reliability and superior overload and short-circuit protection to help reduce equipment damage.
• Reduced Down-Time: A glance at the indicating window pinpoints an open fuse immediately, letting operators request the proper replacement without guesswork.
• Package Size: Industrial Cartridge format.

Certifications & Compliance

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

Technical Specifications

• Refer to manufacturer documentation for complete specifications.

Typical Applications

• Individual Fused Combination Motor Controllers
• Distribution Panelboards
• Protection of Fully-Rated Panelboards and Loadcenters
• Service Entrance Switches
• Switchboard Main and Feeder Switches
• Motor Control Center Mains and Branch Circuits

Why Littelfuse?

Littelfuse engineers the FLNR_ID Indicator Series with a dual-element, solid-state design that combines superior overload and time-delay performance with built-in visual blown-fuse indication across the full 40A-125A rating range. For electricians and facility teams protecting panelboards, motor controllers, and industrial control panels, this combination of UL Listed and CSA Certified reliability with reduced down-time and fewer nuisance openings makes Littelfuse a dependable choice for code-compliant circuit protection.