Method of measuring circuit fault with multimeter using electric test pen
1. Measure the voltage of the phase and neutral wires in the circuit with a voltage tester to see if they are normal. If the neon tube on the phase wire is lit and the neutral wire is not lit, it is considered normal. Explain that the fault is in the indoor circuit and some electrical equipment. It should be done one by one to check whether the sockets, light bulbs, refrigerator, air conditioner, water heater, etc. are normal.
2. The phase line and neutral line are both illuminated when measured with a voltage tester. The fault occurred on the zero line of the circuit. It is necessary to search for the break point of the neutral wire, whether the neutral wire joint has poor contact, and the exact location of the break point.
3. The phase line and neutral line do not light up when measured with a voltage tester. The fault occurs on the phase line of the circuit. The open circuit points and poor contact of the phase lines should be searched for.
4. When the knife switch is in the closed position, the fuse melts. If there is a short circuit between the phase line and the neutral line, the short circuit point and the burnt out part of the electrical appliance should be searched.
5. When the brightness of the neon tube is darker than normal using a voltage tester, the neutral wire is normal. The fault occurs on the phase line, causing reasons such as reduced insulation of the wire, broken outer skin of the wire, leakage of electricity, resulting in voltage drop and inability of household appliances to operate normally.
6. Measure with a voltage tester that both the phase and neutral wires are not lit. First, check if the switches, circuit breakers, and fuses in the circuit are functioning properly and if they are in the activated position.
7. If it is an indoor concealed wire, the concealed wire is broken and cannot be replaced, and it is also impossible to break the wall to check the wire, it should be connected to the nearest power point indoors with exposed wires, so that the power can be reversed from the socket to the circuit, and the fault situation can be found to narrow down the fault range.
8. It is strictly prohibited to mix copper and aluminum wires. Prolonged contact oxidation and wire breakage can endanger the personal safety of pedestrians.
9. When the lighting switch or leakage protector cannot be closed, first remove the load line and test the switch or leakage protector. If it is normal, check the load. Use a multimeter to measure the resistance (when normal) and the voltage should not be zero. The measured voltage should be 220V. Otherwise, if there is a short circuit in the load, replace or repair the wires or lamps in a timely manner.
