The method of distinguishing live wire, neutral wire and ground wire by multimeter
The live wire is the phase wire, which is equivalent to the positive stage of direct current. The industry standard is to use yellow, green and red to represent the ABC three-phase live wire; the neutral wire is equivalent to the negative pole of direct current, which is usually represented by blue and black, and is represented by the word "N". But alternating current has no positive and negative points. The current starts from the live wire, flows through the electrical equipment, and then flows back to the neutral point of the transformer through the neutral wire to complete the circuit.
If the wires in the junction box are all the same color, how can we distinguish the neutral wire from the live wire?
Method 1, voltage method, take the socket line as an example
If the ground wire is determined, turn the multimeter to the highest voltage range, take the ground wire as the common point, and measure the voltage of the ground wire and the other two wires respectively. The one with no voltage is the neutral wire, and the one with voltage is the live wire.
If we don't know the ground wire, we have to use leakage switches and light bulbs or other electrical appliances (I only know this method, huh, huh). After finding the live wire by measuring the voltage, connect it to the "L" terminal on the upper end of the leakage protector, choose one of the other two to connect to the "N" terminal, connect the load terminal to the light bulb, and then send power, it will trip the ground Line that will not trip is the neutral line.
Method 2, induction method, this method is only applicable to those without a ground wire, if there is a ground wire, it must be operated according to method 1
Also turn the multimeter to the highest voltage level, hang the black test lead in the air or wrap it around your finger a few times (the displayed value will be higher in this way), touch the two wires with the red test lead, the live wire with voltage or higher voltage, no voltage or The lower voltage is the neutral line.
There are also some multimeters that have a special gear for measuring the live wire. We only need to adjust the gear to the live wire. This gear is generally represented by "H", and the operation method is the same as above.
Common households may not have multimeters, but we should prepare one for measuring electric pens. Now there is a kind of induction electric pen that is very easy to use. If the measurement is live wire, it will light up red, and if the measurement is neutral line, it will light up green, which is very convenient. Use it, recommend it to everyone here. Friends who like it can go to the Internet to look it up.
Finally, let me say that the distinction between the neutral wire and the live wire is a live operation, and everyone must pay attention to safety.
