The isolation switch is mainly used to reliably isolate the parts that need to be cut off from the live parts in the high-voltage distribution device, in order to ensure the safety of maintenance work. The contacts of the isolation switch are all exposed in the air and have obvious disconnection points. The isolation switch does not have an arc extinguishing device, so it cannot be used to cut off load current or short-circuit current. Otherwise, under high voltage, the disconnection point will generate a strong arc and it is difficult to extinguish it on its own. It may even cause arcing (phase to ground or phase to phase short circuit), burn out equipment, and endanger personal safety, which is a serious accident called "pulling the isolation switch with load". Isolation switches can also be used to switch certain circuits to change the operation mode of the system. For example, in a dual bus circuit, an isolation switch can be used to switch the running circuit from one bus to another. At the same time, it can also be used to operate some small current circuits. (1) After opening, establish a reliable insulation gap and separate the equipment or line that needs maintenance from the power supply with a clear disconnection point to ensure the safety of maintenance personnel and equipment. (2) Change the wiring according to operational needs. Author: Electrical Design Teacher Di https://www.bilibili.com/read/cv5872596/ Source: Bilibili