A4J400 - 400 Amp Fuse

A4J400 - 400 Amp Fuse

The Mersen A4J400 Amp-Trap® Class J fuse is designed for your electrical systems that need fast, dependable protection during overloads and short-circuit conditions. Rated at 400 amps, this fast-acting fuse helps protect your electrical equipment and power distribution systems by interrupting fault current before it can cause more serious damage. In commercial and industrial environments where downtime can quickly become expensive, reliable overcurrent protection is an important part of keeping systems operating safely.

The A4J400 reacts quickly when fault conditions occur, helping reduce stress on motors, transformers, control panels, HVAC equipment, and other connected electrical components. Its current-limiting design helps lower the amount of fault energy moving through the circuit, which can help you reduce equipment damage and improve overall system protection.

This fuse also features a Class J rejection-style design that helps prevent incorrect fuse replacement with lower-rated alternatives. That added level of protection can help support safer maintenance practices and more reliable electrical system performance. The blade-style terminals provide secure installation in compatible fuse holders, while the GMG insulating body is built for long-term use in demanding operating environments.

With a 600VAC / 300VDC rating and a high 200 kA interrupting capacity, the Mersen A4J400 is commonly used in industrial machinery, branch circuits, motor control centers, commercial electrical systems, and power distribution equipment where fast fault interruption is important.

Key Features and Benefits

• 400 amp Class J fast-acting fuse: Designed for dependable overcurrent protection.
• Helps protect equipment from overloads and short circuits: Supports reliable circuit protection.
• Fast response: Helps reduce damage during fault conditions.
• Current-limiting design: Helps lower fault energy.
• Class J construction: Helps prevent incorrect fuse replacement.
• High 200 kA interrupting rating: Designed for demanding fault-current conditions.
• Suitable for AC and DC applications: Supports commercial and industrial electrical systems.
• Blade terminal design: Provides secure installation.
• Brass alloy terminals: Provide dependable conductivity.
• Durable GMG body material: Designed for industrial and commercial environments.
• ROHS compliant: Supports environmental compliance requirements.
  

Technical Specifications

• Manufacturer: Mersen
  
• Catalog Number: A4J400
  
• Series: Amp-Trap® A4J
  
• Fuse Class: Class J
  
• Fuse Type: Fast-Acting
  
• Amp Rating: 400A
  
• Voltage Rating: 600VAC / 300VDC
  
• Frequency: 50/60 Hz
  
• Interrupting Rating: 200 kA AC
  
• Current Type: AC/DC
  
• Mounting Style: Clip
  
• Terminal Type: Blade
  
• Terminal Material: Brass Alloy
  
• Body Material: GMG
  
• Product Diameter: 54 mm
  
• Product Length: 181.1 mm
  
• Product Weight: 0.7938 kg
  
• UPC/EAN: 782001960452
  

Material Compliance and Certifications

• ROHS Compliant: Designed to support environmental compliance requirements.
• Low Voltage UL/CSA Applications: Designed for Low Voltage UL/CSA fuse applications.
• Suitable for industrial and commercial electrical systems: Designed for dependable overcurrent protection.
  

Where It Works Best

• The A4J400 works well in industrial equipment, manufacturing systems, HVAC applications, motor control centers, branch circuits, and electrical distribution systems where fast overcurrent protection is needed. It is especially useful in applications with high available fault current where protecting valuable electrical equipment and reducing unexpected downtime are important priorities.