Cooper Bussmann LPS-RK-4SP Time Delay Fuse 4A RK1

Product Description

The COOPER BUSSMANN LPS-RK-4SP is a Class RK1 time delay cartridge fuse rated at 4 amps for general purpose overcurrent protection in industrial and commercial electrical systems. It features a dual-element design that tolerates brief inrush currents while still providing fast response to sustained overloads and short circuits. The fuse body measures 5 inches in overall length and 20.6 mm in diameter, fitting standard RK1 fuse holders. With an interrupting rating of 100 kA at DC and 300 kA at AC (RMS), it handles high-fault-current environments where reliable protection is critical. Licensed electricians and maintenance technicians are the primary installers.

This fuse is suited for general purpose branch circuit and feeder protection in residential, commercial, and light industrial applications. The time delay characteristic makes it a practical choice for motor circuits, transformer primaries, and control panels where startup inrush current would otherwise cause nuisance tripping with a standard fast-acting fuse. It mounts in a compatible RK1 fuse holder and is sold individually, with a minimum order quantity of 10 units.

Key Features

• Class RK1 dual-element time delay design tolerates motor inrush without nuisance opening
• 4 amp rating suitable for small motor and control circuit protection
• 300 kA interrupting rating at AC (RMS) for high-fault-current installations
• 100 kA interrupting rating at DC for DC bus and battery-backed systems
• Non-indicating body keeps installation profile low in tight panel layouts
• CE, CSA, and UL Listed certifications support use across North American and international job sites

Compatibility

Designed for use in standard Class RK1 fuse holders. Verify holder ampere rating and voltage rating match the circuit requirements before installation.

Installation Notes

Installation must be performed by a qualified 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 any fuse. Confirm the fuse holder is rated for Class RK1 cartridge fuses and that the circuit voltage does not exceed the fuse voltage rating. Do not substitute a higher-amperage fuse to resolve repeated openings - investigate the root cause of the overcurrent condition first.