The method of distinguishing the neutral wire and the live wire using a multimeter
Set the dial of the pointer multimeter (digital meter) to the position of AC voltage 500V. Hold the insulated part at the end of the red probe with your right hand, and press the metal tip of the probe against the tested wire; Pinch the metal tip of the black pen with your left finger. If the needle displays voltage (which is related to the dryness of the skin, shoes, etc.), it indicates that the tested wire is a live wire, otherwise it is a neutral wire. Place the red probe on the tested wire and the black probe on the ground wire or a metal conductor in good contact with the ground. If the pointer indicates a voltage close to 220V or this value, it proves that the tested wire is a live wire. The neutral wire has no voltage to ground, or only a few volts, but there is still a significant difference compared to the live wire.
Attention: One probe should be connected to the object being tested, and the other probe must be connected to an object with good conductivity to the ground. If connected to a dry wall or ground, even if there is electricity, it may not be possible to measure the voltage.
Palm winding test method:
Wrap the black probe around the left or right hand a few times, and place the end of the red probe on the tested wire with the other hand. If the pointer of the multimeter deviates to the right and there is a certain voltage, it indicates that it is a live wire; The line that has no response is the zero line. However, this method uses induced current for measurement, which is easily affected by environmental magnetic or electric fields, and the measurement results may not be accurate.
summarize
Although the above methods can all determine whether the neutral wire, live wire, and objects are charged, they all have certain drawbacks.
For example, in the first method, if the skin is very dry and the shoes have good insulation ability, the multimeter may display a low voltage, which may affect the judgment of the results.
For example, in the second case, if the ground wire breaks or if the other conductor connected to the other probe has poor contact with the ground, it may also cause misjudgment.
For example, in the third case, if there is a strong magnetic or electric field around, the measurement results will be completely inaccurate. Translate into English
