Mersen A070UD32KI400 Protistor Fuse, 400A 700V AC, Size 32 aR, High-Speed Square Body with KI Bolted Contacts - Pack of 3

The Mersen Protistor® A070UD32KI400 (Item Number G300191) is a high-performance, ultra-fast acting square body fuse-link engineered for the protection of power semiconductor devices. Rated at 400A and 700V AC, this Size 32 aR class fuse is designed for heavy-duty industrial applications, including power converters, rectifiers, and large-scale UPS systems. It provides exceptional current limitation and extremely low let-through energy (I²t), preventing catastrophic damage to sensitive electronic components such as thyristors, GTOs, and IGBTs during short-circuit conditions.

The unit is constructed with a high-strength ceramic body and silver-plated copper KI-style bolted contacts, ensuring low power loss and high mechanical reliability in rigorous environments. The internal design leverages pure silver melting elements combined with high-purity silica sand for rapid arc quenching, achieving a high breaking capacity of 200kA. This model is equipped with an integrated mechanical K-type striker for visual trip indication and is compatible with microswitches for remote fault monitoring.

Technical Specifications

• Manufacturer: Mersen
• Catalog Number: A070UD32KI400
• Item Number: G300191
• Amperage Rating: 400A
• Voltage Rating: 700V AC (IEC / UL)
• Interrupting Rating (Breaking Capacity): 200kA at 700V AC
• Operating Class: aR (Ultra-Fast Acting)
• Product Size: 32
• Mounting Configuration: KI (Metric Bolted Studs)
• Indication System: Integrated Mechanical Striker (K-Type)
• Pre-arcing I²t: 18 kA²s
• Total Clearing I²t at Rated Voltage: 120 kA²s
• Power Dissipation at Rated Current: 70W
• Standards Compliance: IEC 60269-4, UL 248-13 Recognized, RoHS Compliant
• Quantity: Pack of 3