Mersen A3T400 400 A / 300 V Class T Fast-Acting Power Fuse

The Mersen A3T400 is a compact, high-performance Class T fuse engineered for superior current-limiting protection in critical electrical systems. Its fast-acting, small-form design enhances safety and allows for convenient retrofit or new installations in confined spaces.

Key Features & Benefits

Fast-Acting Class T Design – Provides rapid current interruption with low let-through, protecting sensitive equipment from overload and short-circuit events

High Voltage & Current Ratings – Rated 400 A at up to 300 VAC or 160 VDC for heavy-duty power distribution

Exceptional Interrupt Capacity – Withstands up to 200 kA (AC) and 50 kA (DC), ensuring maximum safety under fault conditions

Compact Cartridge Shape – Measures approximately 1.33″ diameter × 2.75″ length (33.8 mm × 69.9 mm), ideal for space-constrained panels

Permanent Identification – Blades are stamped with the catalog number for traceability and error-free replacement

Durable Construction – Made from glass–melamine laminate with copper contacts—designed for long-term reliability

Technical Specifications

• Fuse Class: Class T (fast-acting)
• Voltage Rating: 300 VAC / 160 VDC
• Current Rating: 400 A
• Interrupting Capacity: 200 kA (AC) / 50 kA (DC)
• Blade-Terminal Cartridge Size: Ø 1.33″ × 2.75″ L
• Approvals: UL 248‑15, CSA C22.2, RoHS
• Body Material: Glass‑melamine laminate; Contact Material: Copper
  
  

Common Applications

• Load centers, panelboards & switchboards
• Industrial circuits and metering systems
• Generator and backup power systems
• OEM and retrofit protection in compact electrical assemblies
  
  

Why Choose Mersen A3T400?

Its combination of high current interruption, compact dimensions, and Class T fast-acting performance makes the A3T400 perfect for designers and technicians needing reliable protection in tight control cabinets. It's UL- and CSA-certified for seamless use in critical power environments.