Littelfuse FLNR 45 FLNR045 Fuse

The Littelfuse FLNR 45 is a high-performance Class RK5 fuse designed for critical circuit protection in industrial and HVACR systems. As a 250V time-delay fuse, the FLNR045 is engineered to handle the high inrush currents typically associated with motor protection and inductive loads without nuisance tripping. This 45 amp cartridge fuse features dual-element construction, providing superior overcurrent protection and short-circuit coordination. With an interrupting rating of 200,000 Amps RMS Symmetrical for AC and 20,000 Amps for 125VDC, it ensures reliable containment of electrical faults. These Slo-Blo fuses are the industry standard for service entrance switches, panelboards, and motor control centers, offering current-limiting capabilities that significantly reduce peak let-thru current and electromagnetic thermal energy. For contractors, the Littelfuse FLNR 45 is a direct replacement for existing RK5 applications requiring localized protective device coordination.

Key Benefits for Contractors

• Dual-Element Design: Provides accurate time-delay characteristics to prevent unnecessary downtime during motor startups.
• Current-Limiting Performance: Restricts potentially damaging short-circuit currents to protect downstream components.
• Versatile Application: Rated for both 250VAC and 125VDC, making it suitable for a wide range of power distribution and control circuits.
• Industrial Standard Compliance: Meets UL Class RK5 requirements for safety and performance in heavy-duty environments.

Common Questions

Is the FLNR045 suitable for service entrance equipment?
Yes, as a Class RK5 fuse, it is rated for use in service entrance switches and main distribution panels providing the hardware is sized for 250V protection.

Can I use an FLNR 45 to replace a K5 fuse?
While they may share physical dimensions, the FLNR045 offers superior current-limiting capabilities and a higher interrupting rating compared to standard K5 fuses, making it a safe upgrade for existing installations.

Why choose a time-delay fuse for HVAC compressors?
The time-delay/Slo-Blo characteristic allows the fuse to withstand the temporary current spikes during compressor startup without opening, protecting the circuit while maintaining operational reliability.

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.