Cooper Bussmann LPS-RK-70SP Cartridge Time Delay Fuse RK1

Product Description

The COOPER BUSSMANN LPS-RK-70SP is a Class RK1 cartridge-style time delay fuse rated at 70 amps. It is engineered for general-purpose overcurrent protection in industrial, commercial, and trade electrical systems. The fuse features a two-element design that tolerates harmless inrush currents while still opening quickly on sustained overloads or short circuits. With an interrupting capacity of 100 kA DC and 300 kA AC (RMS), it provides robust fault protection. At 7-7/8 inches overall length with a bolt-on mount, it installs into standard fuse blocks and disconnect switches. Licensed electricians and electrical maintenance technicians are the primary installers.

The LPS-RK-70SP is suited for protecting motor branch circuits, feeders, and other general-purpose loads where a time delay characteristic is required to ride through motor starting inrush. Its RK1 classification means it carries a higher degree of current limitation than standard RK5 fuses, making it appropriate for installations where tighter arc-flash and equipment protection is required. This fuse is commonly found in industrial panels, HVAC disconnect switches, and commercial electrical distribution equipment.

Key Features

• Class RK1 rating for enhanced current-limiting performance compared to RK5 class fuses
• 70-amp rating with time delay characteristic handles motor inrush without nuisance opening
• Dual-element construction separates overload and short-circuit protection functions
• High interrupting capacity: 100 kA at DC, 300 kA at AC (RMS)
• Bolt-on mount type for secure installation in compatible fuse blocks and disconnects
• Non-indicating design; CE Certified, CSA Certified, and UL Listed

Compatibility

Designed as an OEM-style replacement or upgrade fuse for Class RK1 bolt-on cartridge fuse holders and disconnect switches rated for 70-amp time delay fuses.

Installation Notes

Installation must be performed by a qualified electrician in accordance with the National Electrical Code (NEC) and all applicable local codes. Always open and lock out the disconnect switch and verify the circuit is de-energized before handling or replacing fuses. Confirm the fuse holder is rated for Class RK1 cartridge fuses of this amperage and overall length before installation. Do not use this fuse as a direct replacement in holders rated only for Class RK5 without verifying compatibility with the equipment manufacturer.