It can be used in indoor 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 contractors, it can protect electric transformers and other electric facilities against overloading or circuit break. It is also a necessary accessory for high-voltage switch.It can be used in indoor 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 contractors, it can protect electric transformers and other electric facilities against overloading or circuit break. It is also a necessary accessory for high-voltage switch.