Leakage protector (leakage protection switch) is an electrical safety device. The leakage protector is installed in the low-voltage circuit. When the leakage and electric shock occur and the action current value limited by the protector is reached, it will immediately act and automatically disconnect the power supply for protection within the limited time. Since the invention and use of electricity, electricity has not only brought a lot of convenience to mankind, but also brought disaster to mankind. It may burn out electrical appliances, cause fire, or cause electric shock. If there is a device that can make people use electricity safely, many unnecessary losses will be avoided. Therefore, when a variety of electrical appliances came one after another, a variety of protectors were also born. When leakage occurs, when the leakage current is greater than (generally 10mA/30mA, which is the safety current of human body), the switch will jump off and power off to prevent people from electric shock due to circuit short circuit. It is also used to protect electrical appliances from personal electric shock and electric fire in case of short circuit to ground due to circuit or electrical insulation damage.