How to use a multimeter to check for short circuit, open circuit, and leakage?
There are many ways to use multimeters. Below I list the common methods of using multimeters to check for short circuit, open circuit, and leakage. I hope it will be helpful to everyone. Any deficiencies are welcome to be supplemented.
Check short circuit with multimeter
Check whether there is a short circuit point in the line. First, cut off the circuit breaker, then turn off all switches and all devices in the line (unplug all devices that can be unplugged).
Select the "beep mode" of the multimeter and measure at the lower port of the circuit breaker - two test leads are in contact with the neutral and live wires at the lower port of the circuit breaker. If the multimeter beeps, it proves that there is a short circuit in the line; otherwise, there is no short circuit.
Check circuit break with multimeter
Still turn off all switches and select the "buzzer" setting on the multimeter. Be sure to measure the direction of the line and find both ends of the wire.
When measuring, the two test leads of the multimeter touch both ends of the wire respectively. If a buzzing sound is emitted, it proves that the wire is not broken; if there is no buzzing sound, it proves that there is a breakpoint in the wire.
What should I do if the two ends of the wire are too far apart? Find a wire that is confirmed to be intact and peel off both ends. One end of the wire is connected to the multimeter, and the other end is used as a test lead to contact the line to be measured - this is to use the wire to extend the length of the multimeter's lead. This method is often used in actual operations.
Multimeter to check for leakage
Don't turn off the circuit breaker this time, just turn off all switches in the line and unplug all plugs. Select the "750V~ range" with the multimeter and measure at the circuit terminal (measure at sockets, switches, etc., not in the distribution box).
Measure the voltage between the live wire-neutral wire and the live wire-ground wire respectively. If the two measured values are the same, or the first value is smaller than the second, it proves that there is no leakage in the line.
If the first measurement value is greater than the second measurement, it proves that there is leakage in the line - the greater the difference between the two, the more serious the leakage is.
