Leakage protector must be installed in the main distribution box (distribution box) and switch box, and the selection of rated leakage action parameters shall comply with the following regulations:Leakage protector must be installed in the main distribution box (distribution box) and switch box, and the selection of rated leakage action parameters shall comply with the following regulations:Without system protection, the power system itself, which is intended to be of benefit to the facility in question, would itself become a hazard. The major concern for system protection is protection against the effects of destructive, abnormally high currents. These abnormal currents, if left. The temporary power specification stipulates that the power distribution system should be equipped with a distribution cabinet or a main distribution box, a distribution box, and a switch box, and implement three-level power distribution. "Two level protection" mainly refers to the use of leakage protection measures. In addition to installing leakage protectors in the final switch box, a first level leakage protector should also be installed. Earth leakage current is not specifically defined in BS 7671:2018+A1:2020, it is referred to as protective conductor current. Because the human body passes 30mA with fatal danger. The operating current of the leakage switch is 15-30mA At present, the distribution line in the city is generally 4 square, a little has been used 6 square. the current imbalance that muses the device to operate) not exceeding 30 mA and an operating time not exceeding 40 ms when the residual operating current is 150 mA.