How to distinguish live wire, neutral wire and ground wire by multimeter
The live wire is the phase wire, which is equivalent to the positive level of direct current. The industry standard is to use yellow, green and red to represent ABC three-phase live wire. The zero line is equivalent to the negative pole of direct current, usually represented by blue and black, and is represented by the word "n". However, there is no difference between positive and negative alternating current, and 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 zero line to complete the loop.
If the wires in the junction box are all the same color, how can we distinguish the zero line from the live line?
Method one, voltage method, taking socket wire as an example.
If the ground wire is determined, the range gear of the multimeter hits the highest level of the voltage gear, and the ground wire is taken as the common point to measure the voltage of the ground wire and the other two wires respectively. If there is no voltage, it is the zero wire, and if there is voltage, it is the live wire.
If we don't know the ground wire, we must use the leakage switch, light bulb or other electrical appliances (I only know this method, hehe). After finding the live wire by measuring the voltage, connect it to the "L" terminal at the upper end of the leakage protector, and choose one of the other two terminals to connect it to the "N" terminal, and then connect the load to the light bulb, and then send electricity. If it trips, it will be the ground wire, but it will not trip, it will be the zero wire.
Method 2, induction method, this method is only applicable to those without ground wire, and if there is ground wire, it should be operated according to method 1.
Similarly, hit the multimeter to the highest voltage level, and the black stylus is suspended or wound around your finger for several times (the displayed value is higher). The red stylus touches two wires, the live wire with voltage or higher voltage, and the zero wire with no voltage or lower voltage.
There are also some multimeters that have a special gear for measuring the live wire. We just 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.
Ordinary families don't necessarily have multimeters, but we should all have one for measuring pens. Now there is an induction pen that is very easy to use. If it is measuring a live wire, it will turn red, and if it is measuring a zero wire, it will turn green, which is convenient and easy to use. I recommend it to everyone here. If you have a favorite friend, you can check it online.
