Disconnector is a switch device mainly used for "isolating power supply, switching operation, connecting and cutting off small current circuits", without arc extinguishing function. When the isolation switch is in the separate position, there should be insulation distance and obvious disconnection signs between the contacts that meet the specified requirements; A switch device that can carry the current under normal circuit conditions and the current under abnormal conditions (such as short circuit) within a specified time when in the closed position.