This series of fuse can be used inindoor system of 50HZ and rated voltage of 3. 6KV, 7. 2KV, 12KV, 24KV, 40. 5KV: Used together with other switch facilities such as loading switches, vacuum contactors, it can protects electric transformers and other electric facilities against overloading or circuit breaker, it is also a necessary accessory for high voltage switch box, circular circuitcabinet, high/low voltage top-loading transformer substation.