Cooper Bussmann FRS-R-40 RK5 40A Time Delay Fuse

Product Description

The COOPER BUSSMANN FRS-R-40 is a cartridge-style, time delay fuse rated at 40 amps in the RK5 fuse class. Designed for general-purpose overcurrent protection, this dual-element fuse tolerates temporary motor-inrush and transformer-magnetizing currents without nuisance opening, while still responding quickly to short-circuit faults. The fuse body measures 27 mm in diameter and 5.5 inches in overall length. It carries a 20 kA interrupt rating at DC 200 volts RMS, making it suitable for circuits where high available fault current is a concern. Licensed electricians and industrial maintenance techs are the primary installers.

The FRS-R-40 is applied in motor branch circuits, HVAC equipment, transformers, and general industrial control panels where time delay characteristics are required to ride through startup surges. The RK5 class designation means it fits standard Class RK5 fuse holders. It is suitable for residential and light commercial applications as well as heavier industrial installations where the amperage and interrupt rating fall within equipment requirements. Always verify the panel or fuse holder is rated for Class RK5 cartridge fuses before installation.

Key Features

• Dual-element construction provides time delay on overload while maintaining fast response to short circuits
• 40 amp rating with 20 kA interrupt capacity at DC 200 volts RMS
• RK5 class fuse fits standard Class RK5 fuse holders and disconnects
• Non-indicating design in a compact cartridge body: 27 mm diameter, 5.5 inches overall length
• CE Certified, CSA C22.2 No. 248.12 Class 1422-02 File 53787 Certified, and UL Listed 248-12 Class RK5 Guide JDDZ File E4273

Compatibility

Designed for use in Class RK5 fuse holders and fusible disconnect switches rated for cartridge fuses. Consult equipment documentation to confirm the fuse holder accepts Class RK5 fuses at 40 amps before installation.

Installation Notes

Installation must be performed by a qualified electrician in accordance with applicable NEC requirements. Always de-energize and lock out the circuit before replacing a fuse. Confirm the fuse holder, disconnect, and wiring are all rated for the applied voltage and available fault current. Do not substitute a different fuse class or higher ampere rating to restore service without verifying circuit protection requirements.