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.

Technical Specifications

• Ampere Rating: 250 amps
• Voltage Rating: 600 volts AC
• Fuse Class: Class J
• Length: 7.250 inches
• Width: 2.120 inches
• Height: 2.120 inches
• Weight: 1.750 pounds
• Quantity per Pack: 1
• UPC: 78200196039

Standard Information

• Brand: MERIT BRASS
• Manufacturer Part Number: A4J250