An isolating switch is a switch device primarily used for "isolating power, switching operations, and connecting or disconnecting low-current circuits" without arc-quenching capabilities. When in the open position, the switch contacts have a specified insulating distance and clear disconnecting marks. In the closed position, it is capable of carrying the current under normal circuit conditions and the current under abnormal conditions (such as a short circuit) within a specified time. Generally used as a high-voltage isolating switch, i.e., switches with rated voltages above 1kV, it has a relatively simple working principle and structure. However, due to its high usage volume and stringent reliability requirements, it significantly impacts the design, establishment, and safe operation of substation and power plant facilities. The main feature of an isolating switch is its lack of arc-quenching ability, allowing circuit opening and closing only under no-load current conditions. This entry covers the functions, features, types, applications, anti-misoperation improvements, maintenance, and common issues of isolating switches.