Cooper Bussmann LPJ-4SP Class J Time Delay Fuse 4A

Product Description

The COOPER BUSSMANN LPJ-4SP is a Class J time-delay cartridge fuse rated at 4 amps, designed for general-purpose overcurrent protection in industrial and commercial electrical systems. It provides a two-element time-delay response, allowing temporary inrush currents to pass without nuisance tripping while still protecting downstream equipment from sustained overloads and short-circuit faults. The LPJ-4SP carries an interrupting rating of 100 kA at DC and 300 kA at AC (RMS), making it suitable for high-fault-current environments. The cartridge body measures 20.6 mm in diameter and 57.2 mm in length, mounting in a standard Class J fuse holder.

This fuse is used in commercial and industrial electrical panels, motor branch circuits, control panels, and equipment requiring Class J fuse protection. Its time-delay characteristic suits motor loads, transformers, and other inductive loads that draw elevated startup current. Licensed electricians typically install this fuse as part of a properly rated Class J fuse holder assembly in systems where high interrupting capacity and compact form factor are both required.

Key Features

• Class J rating with 300 kA AC (RMS) interrupting capacity for high-fault-current applications
• Time-delay two-element design prevents nuisance tripping on motor inrush and transformer magnetizing current
• Non-indicating body keeps form factor compact for tight panel installations
• Mounts in standard Class J fuse holders
• UL Listed (Guide JDDZ, File E4273), CSA Certified, CE Certified, and RoHS Compliant

Compatibility

Designed for use in standard Class J fuse holders. Compatible with any panel, disconnect, or control enclosure rated for Class J cartridge fuses at 4 amps.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the NEC and applicable local codes. De-energize and lock out the circuit before removing or installing any fuse. Verify that the fuse holder is rated for Class J fuses and that the circuit voltage and amperage do not exceed the fuse ratings. Do not substitute a fuse of a different class or higher amperage rating as a replacement.