Cooper Bussmann FRS-R-100 RK5 Time Delay Fuse 100A

Product Description

The COOPER BUSSMANN FRS-R-100 is a cartridge-style, time delay fuse rated at 100 amps and classified under UL Class RK5. It is designed for general-purpose overcurrent protection in industrial and commercial electrical systems where inrush current from motors, transformers, and capacitive loads requires a time delay characteristic to avoid nuisance tripping. At 7-7/8 inches overall length and a two-element internal construction, this fuse provides both overload protection and short-circuit interruption up to 20 kA DC at 200 volts RMS. Installation is handled by licensed electricians working on branch circuit and feeder applications.

The FRS-R-100 is suited for use in motor branch circuits, combination motor starters, and general-purpose panelboard and disconnect applications in commercial and light industrial settings. Its bolt-on mount type makes it compatible with standard Class RK5 fuseholders and fuse blocks. The time delay characteristic accommodates the starting inrush of single-phase and three-phase motor loads without requiring an oversized fuse rating, keeping circuit protection properly matched to running current.

Key Features

• 100 amp rating with time delay characteristic for motor and transformer inrush tolerance
• UL Class RK5 listing under Guide JDDZ File E4273 for standardized fuseholder compatibility
• CSA C22.2 No. 248.12 certified and CE certified for multi-jurisdiction installations
• Two-element construction provides separate overload and short-circuit protection paths
• Bolt-on mount type for secure, low-resistance termination in fuse blocks and disconnects
• 20 kA interrupting rating at DC 200 volts RMS for reliable fault clearing

Compatibility

Designed as an OEM-style replacement for Class RK5 cartridge fuse applications using standard bolt-on fuseholders rated for 100 amp, Class RK5 fuses.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and any applicable local codes. De-energize and lock out the circuit at the upstream disconnect before removing or installing the fuse. Verify that the fuseholder is rated for Class RK5 cartridges and for the full voltage and amperage of the circuit. Do not substitute a fuse of a different class, higher amperage rating, or non-time-delay type without engineering review of the circuit protection coordination.