Cooper Bussmann FRN-R-80 RK5 Cartridge Time Delay Fuse 80A

Product Description

The COOPER BUSSMANN FRN-R-80 is a cartridge-style, time-delay fuse rated at 80 amps and 250 volts, classified under UL Class RK5. It features a dual-element design that tolerates temporary motor-inrush and transformer-magnetizing currents without nuisance opening, while still providing fast response to sustained overloads and short-circuit faults. The fuse body measures 26.9 mm in diameter and 5.875 inches in overall length, sized for standard Class RK5 fuse holders and disconnects. Electricians and HVAC technicians install this fuse in motor branch circuits, HVAC disconnect boxes, and general-purpose feeder protection applications where reliable overcurrent protection is required.

The FRN-R-80 is suited for residential and light commercial HVAC systems, motor circuits, and general industrial feeder applications where time-delay overcurrent protection is required. Its bolt-on mount type integrates directly into standard fusible disconnect switches and panelboard fuse holders designed for Class RK5 cartridge fuses. Where equipment draws high inrush current at startup, the dual-element design allows the circuit to stabilize before the fuse evaluates the load, reducing unwanted interruptions during normal startup cycles.

Key Features

• Time-delay dual-element design tolerates motor inrush without nuisance tripping
• 80-amp continuous rating at 250 volts AC
• 20 kA interrupting rating at DC 200 RMS for short-circuit protection
• Class RK5 classification for use in RK5-rated fuse holders and disconnects
• Bolt-on mount type for secure seating in standard fusible disconnects
• CE Certified, CSA C22.2 No. 248.12 Certified, and UL Listed 248-12 Class RK5

Compatibility

Designed as an OEM-style replacement or new-installation fuse for Class RK5 fusible disconnect switches and fuse holders rated for cartridge fuses at 250 volts and 80 amps or greater.

Installation Notes

Installation must be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and applicable local codes. Always de-energize and lock out the disconnect or panel before removing or installing fuses. Verify that the fuse holder or disconnect is rated for Class RK5 cartridges and is suitable for the circuit voltage and amperage before installation. Do not substitute a fuse of a higher amperage rating as a replacement, as this will compromise overcurrent protection.