Cooper Bussmann LPS-RK-25SP Time Delay Fuse 25A RK1

Product Description

The COOPER BUSSMANN LPS-RK-25SP is a Class RK1 time delay cartridge fuse rated at 25 amps. It is designed for general-purpose overcurrent protection in industrial and commercial electrical systems. The two-element construction allows the fuse to tolerate temporary inrush currents without nuisance opening, while still responding quickly to sustained fault conditions. It measures 5 inches in overall length and 20.6 millimeters in diameter, and uses a bolt-on mount. With an interrupting rating of 100 kA at DC and 300 kA at AC (RMS), this fuse is suited for circuits where high available fault current demands a robust protection device. Licensed electricians and maintenance technicians are the primary installers.

This fuse is used in industrial control panels, motor branch circuits, and general distribution equipment where Class RK1 protection is specified. The time delay characteristic makes it well-suited for motor circuits and transformer primaries that draw elevated inrush current at startup. It is a non-indicating type, so a fuse tester or clamp meter is typically used to confirm continuity during troubleshooting. Applications span both commercial and light industrial settings wherever RK1-class fusing is called out in the panel schedule or equipment documentation.

Key Features

• Class RK1 rating provides one of the highest levels of overcurrent protection available in the cartridge fuse format
• Two-element time delay design handles motor inrush and transformer magnetizing current without nuisance opening
• High interrupting capacity: 100 kA at DC, 300 kA at AC (RMS)
• Bolt-on mount for secure, low-resistance termination in fuse blocks and disconnect switches
• Non-indicating construction keeps the package compact and cost-effective
• CE Certified, CSA Certified, and UL Listed for broad compliance across North American and international installations

Compatibility

Designed as an OEM-style replacement for Class RK1 cartridge fuse positions requiring a 25-amp, time delay fuse with a 5-inch body length and 20.6-millimeter diameter in bolt-on fuse blocks and fusible disconnect switches.

Installation Notes

Installation must be performed by a qualified electrician in accordance with the NEC and any applicable local codes. Always de-energize and lock out the circuit before opening the fuse block or disconnect enclosure. Confirm that the fuse holder or disconnect is rated for Class RK1 cartridges before installing. Do not use a fuse of a higher amperage rating as a substitute, as this defeats the overcurrent protection for the circuit.