Merit Brass A4J250 Class J Fuse 250 Amp 600V

Product Description

The MERIT BRASS A4J250 is a Class J current-limiting fuse rated at 250 amps and 600 volts AC. Class J fuses are dual-element, time-delay designs built to protect motors, transformers, panelboards, and feeder circuits from both overloads and short-circuit faults. The time-delay element allows for normal motor inrush currents without nuisance tripping, while the fast-acting element clears hard faults quickly to limit arc energy and downstream damage. Licensed electricians install this fuse in Class J fuse holders and disconnect switches where high interrupting capacity and precise ampere ratings are required by code.

This fuse is suited for commercial and industrial electrical installations where branch-circuit or feeder protection is required under NEC guidelines. Typical applications include motor disconnect switches, combination starters, and panelboard feeders in facilities requiring Class J-rated overcurrent protection. The compact form factor fits standard Class J rejection-style fuse blocks that prevent substitution of lower-rated fuse classes.

Key Features

• 250-amp continuous current rating for heavy motor and feeder circuit protection
• 600-volt AC rating covers most commercial distribution voltages
• Class J current-limiting design provides high interrupting capacity to limit fault energy
• Dual-element time-delay construction tolerates motor inrush without nuisance opening
• Rejection-style Class J dimensions prevent substitution of non-current-limiting fuse classes

Compatibility

Designed for use in Class J fuse holders and rejection-style disconnect switches rated for 250-amp, 600-volt Class J fuses. Verify holder ampere and voltage ratings match before installation.

Installation Notes

Installation must be performed by a qualified, licensed electrician in accordance with the National Electrical Code (NEC) and applicable local codes. De-energize and lock out/tag out the circuit completely before removing or installing any fuse. Use insulated fuse pullers rated for the voltage and ampere class involved. Never replace a fuse with one of a higher ampere rating than the circuit is designed and protected for.

WARNING: This product can expose you to chemicals including lead, which are known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.