Simply put, single-phase leakage protection: the fire line flows to the zero line, then the fire line current is equal to the zero line current, when the fire line leakage, a part of the current through the fire line leakage flow to the earth, then the fire line current is not equal to the zero line current, when the error is greater than the action value of the leakage protection, the leakage protection trip.

Leakage protection can only protect a single phase of electric shock. For example, if you get an electric shock with one hand and the current flows through your body to the earth, the leakage protection will trip, but if you contact the fire line with one hand and the zero line with the other hand, forming a circuit, the leakage protection will not protect.

The role of the air switch is to play overload and short circuit protection, if you short circuit, empty meeting play a protective role, so we have to install the air and leakage protection at home.

Leakage protection must be required to access the circuit, if not a professional electrician, please do not arbitrarily change the circuit.