It is used for power supply in important medical places (operating room, intensive care unit). When the direct leakage current of the electrical equipment to the human heart is greater than 10uA, it will cause the patient's micro-electric shock accident, and the leakage protection switch used in general general buildings, the corresponding action is The 1000uA level is far from meeting the needs of the medical field. Therefore, the important places in the medical field are required to use a local "isolated power system" for power supply.