Knowledge of electrical disaster reduction.

(1) when the system is running normally, there is no current on the dedicated protection line, but there is an unbalanced current on the working zero line. The PE line has no voltage to the ground, so the protection of the metal shell of the electrical equipment is connected to the dedicated protection line PE, which is safe and reliable.

(2) the working zero line is used for single phase lighting load circuit.

(3) the special protection line PE is not allowed to be broken, and no leakage switch is allowed.

(4) the main use of leakage protector, the work is zero line shall not repeat grounding, and PE line has repeated earthing, but without leakage protector, so TN - S system leakage protector can also be installed on the main power supply.

(5) the tn-s mode power supply system is safe and reliable, which is suitable for low-voltage power supply systems such as industrial and civil buildings.