Cooper Bussmann LPJ-50SPI 50A Class J Time Delay Fuse

Product Description

The COOPER BUSSMANN LPJ-50SPI is a Class J time delay cartridge fuse rated at 50 amps and designed for general purpose overcurrent protection in demanding electrical systems. With a 2-element indicating construction, this fuse provides both time delay response for motor and transformer inrush tolerance and visible blown indication to speed up fault diagnosis. It 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 27.00 mm in diameter and 60.30 mm in overall length, fitting standard Class J fuse holders.

This fuse is applied in industrial and commercial electrical panels, motor control centers, and equipment requiring Class J fuse protection. The time delay characteristic makes it well suited for circuits with inductive loads such as motors, transformers, and HVAC compressor circuits where brief startup surges must pass without nuisance opening. Licensed electricians and industrial maintenance technicians are the primary installers.

Key Features

• 50-amp Class J time delay rating for inrush-tolerant overcurrent protection
• Dual-element design separates overload and short-circuit response
• Indicating fuse — provides visual confirmation of a blown condition
• High interrupting capacity: 100 kA DC and 300 kA AC (RMS)
• Compact cartridge body: 27.00 mm diameter, 60.30 mm length
• Compliant with UL, CSA, CE, and RoHS requirements

Compatibility

Designed for use in standard Class J fuse holders. Verify holder ampere rating, voltage rating, and physical dimensions match before installation.

Installation Notes

Installation should be performed by a licensed electrician in accordance with the National Electrical Code (NEC) and any applicable local codes. De-energize and lock out the circuit before removing or installing any fuse. Confirm the fuse holder is rated for Class J cartridge fuses and that the circuit voltage and amperage do not exceed the fuse rating. Do not use a fuse puller rated for a different fuse class, as improper handling can damage the indicating element.