Fuse Amp-Trap® 600V 250A Time-Delay Class L A4BY Series

The Fuse Amp-Trap® A4BY Series is a Class L, 600V time-delay fuse designed for protecting service entrance equipment, feeder circuits, and circuit breakers. It is suitable for applications involving mains feeders, load centers, panelboards, switchboards, and metering centers. Manufactured by Mersen, this fuse features a 100% continuous current rating and a minimum 4-second time delay at 500% overload, allowing it to pass normal current surges and coordinate with ground fault relays. Its construction includes a glass melamine insulation body and plated terminals for reliable performance in harsh environments. The bolted mounting and blade connection provide secure installation.

Specifications

• Amperage Rating: 250 A
• Voltage Rating: 600 VAC, 300 VDC
• Interrupt Rating: 200 kA
• Fuse Class: Class L
• Dimensions (L x W x H): 8.63 in x 2 in x 2 in
• Diameter: 2 inches
• Mounting Type: Bolted
• Connection: Blade
• Insulation Material: Glass Melamine (GMG)
• Product Weight: 2.38 lbs
• Manufacturer Part Number: A4BY250

Features

• Current-limiting fuse with 4-second time-delay to handle temporary overloads
• Unique dimensions prevent replacement by other fuse classes
• Blade stamped catalog numbers for permanent identification
• Glass melamine body and plated terminals ensure durability and reliability in harsh environments
• UL and CSA listed for safety and compliance
• Uniform characteristics across all ampere ratings

Downloads & Links

• Spec Sheet
• Spec Sheet FR
• Curves 1
• Curves 2
• Drawings