When testing whether the power supply protector is normal, professional personnel should be invited to use the leakage phase detector to test. If the power supply protector is in the normal protection state, the power supply protector of each circuit will trip separately, and the leakage protector will also trip together. If the power supply protector is in an abnormal state, only the main switch trips, the separate power supply protector does not trip, and the leakage protector does not trip.

The tripping mechanism of the switch is a set of connecting rod devices. When the main contact is closed through the operating mechanism, it will be locked in the closing position by the locking hook. If there is a fault in the circuit, the relevant release will act to release the locking hook in the release mechanism, and the main contact will quickly break under the action of the release spring. According to the different protection functions, the release can be divided into over-current release and voltage-loss release.