Ferraz Shawmut A4BT800 Current Limiting Time Delay Fuse

The Ferraz Shawmut A4BT800 is a UL Class L current-limiting time-delay fuse rated at 800 A and 600 VAC (also 500 VDC), engineered to protect high-capacity electrical distribution systems from overcurrent and short circuits. Its 200 kA interrupting rating at 600 VAC and 10-second time delay at 500% rated current let it tolerate motor startup surges and inductive inrush while safeguarding equipment such as motor control centers, switchboards, feeders, transformers, and other industrial power networks. The fuse features a glass-melamine tube body and blade terminals for bolt-in Class L holders, designed for main, feeder, motor, and transformer protection in industrial settings. Common replacements include Bussmann KLU-800, Littelfuse KLPC800, and Edison LCL800, and the product is commonly specified by system integrators for motor protection in industrial installations. Manufactured by Ferraz Shawmut (now Mersen), the A4BT800 adheres to UL 248-10 and CSA C22.2 No. 248.10 standards.