Use a multimeter to measure the voltage of the neutral and ground wires
1. Connect the neutral wire and live wire in reverse
This situation may be caused by messy wiring, lack of color differentiation of wires, or a stubborn belief that left zero and right fire are the cause.
The handling method is also simple. Since you have a multimeter at hand, use a multimeter to measure the resistance and voltage between three wires, redefine which of the three wires is the live wire, which is the neutral wire, and which is the ground wire, and label them properly. You won't make any mistakes next time.
2. The neutral line has a breakpoint
It is best to measure voltage at the power circuit breaker, and if convenient, at the meter. If measured at the backend of the device, there is a possibility of a broken neutral wire and misjudgment.
When the backend neutral wire is broken, the live wire and neutral wire will be connected through a filament or coil. Although there may be some resistance, it can be ignored and the measured voltage change is not significant. In this situation, it is necessary to remove the light bulb and other electrical appliances, disconnect the neutral and live wire circuits, in order to measure accurately.
3. The resistance of the neutral wire is too high
This situation is basically caused by loose crimping and poor contact. However, the voltage measured in this situation is fluctuating, and there may be heating and scalding at the street level of the wires.
4. The equipment casing is electrified
If the device casing is charged, that is, the live wire leaks, and a regular air switch is used, the leakage current does not reach the short-circuit current, and the air switch will not trip. In this case, measuring the neutral and ground wires may result in a voltage of 220V.
Or even though a leakage protector is used, the ground wire is broken or the grounding resistance is too high. In this case of leakage, there will also be a voltage of 220V when measuring the neutral and ground wires.
5. Connect the ground wire and live wire in reverse
Although this kind of oddity is hard to imagine, when analyzing the problem, we also have to consider and not miss any doubts.
