Littelfuse FLNR 40 FLNR040 Fuse

The Littelfuse FLNR040 is a heavy-duty 250V RK5 40A Time Delay Fuse engineered for motor and transformer protection in commercial HVACR systems. As a dual-element fuse, the FLNR 40 provides superior overcurrent protection by utilizing a Slo-Blo/Time Lag characteristic that allows for high inrush current during motor startup without nuisance tripping. Rated for 40 Amps with a 200,000 AIR (Interrupting Rating) AC, this industrial cartridge fuse ensures circuit integrity during severe short-circuit conditions. Its Class RK5 designation makes it a standard choice for service entrance switches and panelboards where current limiting and time-delay properties are required. The 125 VDC rating at 20,000A further extends its utility to high-capacity DC control circuits, making it a versatile component for field technicians managing complex power distribution loads.

Key Technical Benefits:

• Dual-Element Design: Provides accurate time-delay protection to prevent unnecessary downtime caused by temporary power surges.
• Class RK5 Compliance: Ensures branch circuit protection and compatibility with standard 250V fuse blocks and disconnects.
• Enhanced Safety: High interrupting capacity safely mitigates major electrical faults in residential and light industrial applications.
• Standardized Fit: The Industrial Cartridge form factor allows for drop-in replacement in existing installations requiring a 40 Amp FLNR series fuse.

Common Questions:

What is the difference between FLNR and FLSR fuses?

The FLNR series is rated for 250 VAC, while the FLSR series is rated for 600 VAC. Both are Class RK5 time-delay fuses, but you must match the voltage rating of your system; an FLNR040 is only suitable for circuits 250V and below.

Can I use a Class H fuse instead of an FLNR 40?

While Class H fuses fit the same clips, they do not provide the current-limiting performance or the 200k AIR of a Class RK5 fuse. Upgrading to the Littelfuse FLNR040 improves the safety and coordination of your electrical system.

Is the FLNR040 suitable for DC applications?

Yes, this 40A fuse is rated for up to 125 VDC with a 20,000A interrupting rating, making it suitable for many DC motor controllers and battery systems.

Disclaimer: While we strive for 100% accuracy, product data and specifications are subject to change. Please contact our team to confirm compatibility or technical details before purchasing.