How to measure circuit faults with a test pen and multimeter
Faults in lighting circuits often occur in real work, and hidden faults are invisible to the naked eye. Here we will introduce how to use a test pen and a multimeter to measure circuit faults.
1. Use a test pen to measure whether the phase line and neutral line voltages in the circuit are normal. If the phase line neon tube lights up but the neutral line does not light up, it is normal. It indicates that the fault is in the indoor circuit and some electrical equipment. They should be carried out one by one to check whether sockets, light bulbs, refrigerators, air conditioners, water heaters, etc. are normal.
2. The phase line and neutral line are both bright when measured with an electric test pen. It means that the fault occurs on the neutral line of the circuit. The neutral line break point should be found, whether the neutral line connector is in poor contact and the exact location of the break point.
3. The phase line and neutral line do not light up when measured with an electric test pen. It means that the fault occurs on the phase line of the circuit. Look for the disconnection point of the phase line and poor contact of the connector.
4. When the knife switch is in the closing position, the fuse is blown. It means that there is a short circuit between the phase line and the neutral line. You should look for the short circuit point and some burned electrical appliances.
5. When the phase line is measured with an electric test pen and the brightness of the neon tube is darker than normal, the neutral line is normal. It means that the fault occurs on the phase line, and the reasons are such as the insulation of the wire is reduced, the outer skin of the wire is broken and leaks, causing the voltage to drop and the household appliances to fail to operate normally.
6. Use a test pen to measure the phase line and neutral line. If the phase line and neutral line are not bright, first check whether the switch, knife switch, and fuse in the circuit are normal, and check whether they are in the input position.
7. If it is an indoor hidden wire, the hidden wire is broken and cannot be replaced, and it is impossible to break through the wall to check the wire. You should connect it to the nearest power point indoors with an exposed wire, so that the power is sent back to the circuit from the socket to find the fault and reduce the problem. fault scope.
8. It is strictly forbidden to mix copper and aluminum wires. Over time, the contacts will oxidize and the wires will break, endangering the personal safety of pedestrians.
9. When the lighting switch or leakage protector fails to close, first remove the load line and test the switch or leakage protector with no air. If it is normal, check the loaded load. Use a multimeter to measure the resistance (when normal) and it should not reach zero. Measure The voltage should be 220v. Otherwise, if the load contained is short-circuited, the wires or lamps should be replaced or repaired in time, and the wires or lamps should be checked.
