Mersen A070UD32KI350 Protistor Fuse, 350A 700V AC, Size 32 aR, High-Speed Square Body with KI Bolted Contacts - Pack of 3

The Mersen Protistor® A070UD32KI350 (Item Number F300190) is an ultra-fast acting square body fuse-link designed specifically for the protection of power semiconductor devices. With a 350A rating and 700V AC capacity, this Size 32 aR class fuse is a critical safety component for industrial power systems, including high-power converters, motor drives, and rectifiers. It is engineered to provide exceptionally low let-through energy (I²t) and superior peak current limitation, shielding sensitive power electronics like thyristors and diodes from high-energy short-circuit faults.

The fuse features a high-performance ceramic housing and silver-plated copper KI-style bolted contacts (Metric Bolted Studs), ensuring high mechanical stability and low contact resistance. Its internal construction utilizes pure silver elements and high-purity silica sand for rapid arc extinguishing and a high breaking capacity of 200kA. This model includes an integrated mechanical K-type striker to provide a clear local indication of fuse operation and can be equipped with a microswitch for remote diagnostic signaling.

Technical Specifications

• Manufacturer: Mersen
• Catalog Number: A070UD32KI350
• Item Number: F300190
• Amperage Rating: 350A
• 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: 13 kA²s
• Total Clearing I²t at Rated Voltage: 86 kA²s
• Power Dissipation at Rated Current: 65W
• Standards Compliance: IEC 60269-4, UL 248-13 Recognized, RoHS Compliant
• Quantity: Pack of 3