Cooper Bussmann LPN-RK-40SP RK1 Time Delay Fuse 40A

Product Description

The COOPER BUSSMANN LPN-RK-40SP is a Class RK1 cartridge time delay fuse rated at 40 amps for use in industrial and commercial electrical systems. It features a dual-element design that tolerates temporary inrush currents while still providing reliable short-circuit and overload protection. With an interrupting rating of 100 kA at DC and 300 kA at AC (RMS), this fuse is suitable for high-fault-current environments. At 3 inches in overall length and 20.6 mm in diameter, it mounts in a standard RK1-class fuse holder. Licensed electricians and industrial maintenance technicians are the primary installers.

This fuse is used in motor branch circuits, feeder panels, and equipment protection applications where time delay characteristics are required to ride through motor starting inrush. The Class RK1 rating provides a higher degree of current limitation compared to Class RK5, making it appropriate for installations where tighter protection is specified. It is suitable for both new construction and service replacement in residential, commercial, and light industrial settings.

Key Features

• Class RK1 rating with dual-element, time delay design for inrush tolerance
• 40-amp continuous current rating
• High interrupting capacity: 100 kA at DC, 300 kA at AC (RMS)
• Non-indicating fuse body — no visual blown indicator
• Mounts in standard RK1 cartridge fuse holders
• CE Certified, CSA Certified, and UL Listed

Compatibility

Designed for use in RK1-class cartridge fuse holders in motor circuit, feeder, and branch-circuit protection applications. Verify fuse holder ampere rating and voltage rating before installation.

Installation Notes

Installation should be performed by a qualified, licensed electrician in accordance with the National Electrical Code (NEC) and applicable local codes. Always de-energize and lock out the circuit before removing or installing fuses. Use an insulated fuse puller rated for the voltage class when servicing cartridge fuses. Confirm the replacement fuse ampere rating, voltage rating, and class match the original specification before energizing the circuit.