Why does a multimeter only show 107V when measuring 220V voltage?
In this case, the power should be cut off to investigate the cause. You can test it at other people's homes to see if it's normal. Normally it should be around 200 volts to 240 volts. The peak value during summer irrigation in rural areas can be as low as about 160 volts. This is due to the power supply system. If other people's homes are normal, but one's own home or one of the channels is abnormal, then there is a fault and it should be rectified before power is supplied. To prevent fire damage and electrical accidents. Focus on checking in detail whether there are poor contacts, electrical faults, electrical heavy-duty wires that are too thin and overloaded, etc. It's best to ask an electrician to help troubleshoot. To prevent the malfunction from causing damage to people and property.
First, the external line may be broken due to the neutral line. Second, you can use an electric pen to measure the light and darkness to judge. The internal battery of the third multimeter is insufficient. Use another multimeter for comparison!
First of all, is it possible to use the same multimeter to measure the starting voltage on single-phase line A of the same main power supply to be 220V, but to measure the starting voltage on single-phase line B to be 107V? , the second question is whether the voltage measured with the same multimeter at the beginning of single-phase line A is 220V, and the voltage measured at its end is 107V?
If the same multimeter is used to measure single-phase line A of the same main power supply, the measured starting voltage is 220V, and the measured voltage of single-phase line B is 107V; then the upper and lower ends of the circuit breaker (switch) of single-phase line B are respectively The two wiring points should have poor contact due to oxidation, resulting in an increase in contact resistance and a voltage drop.
If the same multimeter is used to measure single-phase line A or single-phase line B with the same power supply, and the measured starting end voltage is 220V, and the measured end voltage is 107V, then it should be that the line with the measured end voltage of 107V is too long or the line on the line is too long. The load current is greater than the safe carrying capacity of the line conductors, resulting in a voltage drop.
If the voltage measured at the beginning of the single-phase lines A and B of the same power supply is 107V, then it should be that the capacity of the distribution transformer in the low-voltage distribution station area is much smaller than the power consumption capacity of the user, or that the distribution transformer The distribution line from the user is too long and has too little voltage drop.
