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.