How to Identify Live and Neutral Wires Using a Multimeter
1. Set the multimeter to AC mode, and I set it to AC 750V mode. If you want a more intuitive view, you can set it to a smaller AC voltage mode. It depends on the situation!
Suspend the black probe (just put it aside) and insert the red probe into the socket to be tested. The hole with a larger reading is the live wire. You can see that when the red probe is placed in the socket above, the reading displayed is "4". Remember this number.
2. Then put the red probe into the socket below and try again. You can see that the reading this time is "17", which is significantly larger than the previous measurement! This indicates that the hole is the live wire!
3. Next, use a test pen to verify the accuracy of the test results! Insert the test pen into the hole with the highest reading on the multimeter. You can see the neon tube glowing, indicating that it is a live wire!
4. Use a test pen to test the socket on top, and you can see that the neon tube is not emitting light, indicating that it is the neutral wire.
5. Through the above tests, it can be seen that using a multimeter to distinguish between neutral and live wires is feasible!
When the probe is short circuited, the pointer cannot be adjusted to zero or the pointer swings back and forth unstably
(1) Replace with a new battery of the same model;
(2) Replace the series resistor;
(3) Adjust the socket spring to ensure good contact, and remove the oxide layer on the probe plug and socket;
(4) Clean the switch contacts of the multimeter with alcohol and calibrate the contact distance between the moving contacts and the stationary contacts;
(5) Use tweezers to press down the moving contact piece in the middle of the zero potentiometer to ensure good contact with the static contact resistance wire;
Resistance range is not connected or the error is too large
(1) Replace the resistor with the same resistance and power;
(2) Wipe and repair poor contact areas with alcohol;
(3) Replace the shunt resistor of this gear;
(4) Replace with a new battery of the same model;
