Use a multimeter to measure the voltage of the zero and ground wires
What will happen if the zero wire and ground wire are connected in reverse? Is the zero wire and ground wire connected? What is the voltage between the zero wire and ground wire in volts? Related technical articles: Use a multimeter to measure the voltage of 220V between the zero wire and ground wire
In the TN-S power supply system, the zero line and ground wire are both of the same origin and are led out from the neutral grounding of the transformer. One participates in the working circuit and is called the working zero line, while the other serves as the protection circuit and is called the protective zero line.
If a multimeter is used to measure the voltage of 220V on the zero and ground wires, based on my judgment, there may be the following reasons:
1. The neutral and live wires are connected in reverse
If this situation occurs, it may be due to disorderly wiring, lack of color differentiation in the wires, or the stubborn belief that left zero and right fire are causing it.
The handling method is also simple. Since you have a multimeter at hand, use a multimeter to measure the three values separately
The resistance and voltage between the three wires should be redefined, including which is the live wire, which is the zero wire, and which is the ground wire. Mark them properly so that you won't make any mistakes next time.
2. There is a breakpoint on the zero line
It is best to measure the 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 zero line breakage and misjudgment.
The back end zero line is broken, and at this point, the live line and zero line will be connected through the filament or coil. Although there may be some resistance, it can be basically ignored, and the measured voltage change is not significant. In this situation, it is necessary to remove electrical appliances such as light bulbs, disconnect the circuit of the zero and live wires, and the measurement will be accurate.
3. The zero line resistance is too high
This situation is basically caused by loose crimping and poor contact. However, the voltage measured in this situation is erratic, and there may be heating and scalding phenomena at the corners of the wires.
4. The equipment casing is live
If the equipment casing is electrified, which means that the live wire is leaking, and an ordinary 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 zero and ground wires may result in a voltage of 220V.
Alternatively, although a leakage protector is used, the ground wire is disconnected or the ground resistance is too high. In this case, leakage occurs, and there will also be 220V voltage measured on the zero and ground wires.
