Cooper Bussmann LPN-RK-35SP RK1 Time Delay Fuse 35A

Product Description

The COOPER BUSSMANN LPN-RK-35SP is a Class RK1 cartridge time delay fuse rated at 35 amps, designed for general-purpose overcurrent protection in industrial, commercial, and trade electrical applications. With an overall length of 3 inches (76.2 mm) and a body diameter of 20.6 mm, it mounts via bolt-on installation in standard fuse blocks and holders accepting RK1-class cartridge fuses. The dual-element, time delay design allows the fuse to tolerate brief inrush currents during motor starts and transformer energization without nuisance opening, while still providing fast response to sustained fault conditions. Licensed electricians and electrical maintenance technicians are the primary installers.

This fuse is suited for motor branch circuit protection, transformer primary protection, and general-purpose feeder circuits in residential, commercial, and light industrial electrical systems. The RK1 class designation provides a higher level of current limitation compared to standard Class H fuses, making it appropriate for installations where equipment protection and short-circuit current ratings (SCCR) must meet stricter code requirements. The bolt-on mount style integrates into panel-mount and inline fuse holders designed for cylindrical cartridge fuses of this body size.

Key Features

• Class RK1 current-limiting design for enhanced equipment protection over standard Class H fuses
• 35-amp rating with time delay action to ride through motor inrush and transformer energization
• Dual-element construction provides both overload and short-circuit protection in a single fuse body
• Interrupting capacity of 100 kA at DC and 300 kA at AC (RMS) for high fault-current environments
• Bolt-on mount type for secure installation in compatible fuse blocks and holders
• Non-indicating design; visually inspect or test with a multimeter to confirm continuity after a fault event

Compatibility

Designed as an OEM-style replacement for Class RK1 cartridge fuse positions requiring a 35-amp, time delay fuse with a 3-inch overall length and 20.6 mm body diameter in bolt-on fuse holders and blocks.

Installation Notes

Installation and replacement should 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 circuit before opening a fuse holder or fuse block. Confirm the replacement fuse class, amperage rating, and physical dimensions match the original before reinstalling. Verify the fuse holder is rated for Class RK1 fuses, as RK1 fuses require a rejection-style holder that prevents insertion of lower-rated fuse classes.