How to use the live wire identification function of a multimeter?
Ordinary Test Pen: In the past, when electricians were troubleshooting faults, an ordinary test pen was their main tool. Most people basically know how to distinguish between the live wire and the neutral wire with an ordinary test pen. Just use the test pen to measure the live wire and the neutral wire directly. If the test pen lights up, it is the live wire; if it doesn't light up, it is the neutral wire.
Digital Test Pen: Since the emergence of the digital test pen, the ordinary test pen has been rarely used. The digital test pen has more functions. For example, it can check for broken wires without power, distinguish between the neutral wire and the live wire, identify the positive and negative poles of a DC battery, and determine whether there is a short circuit in the wire. So, gradually, the ordinary test pen has been phased out. To distinguish between the live wire and the neutral wire with a digital test pen, directly measure them with the test pen and observe the voltage displayed on the digital test pen. If the maximum voltage shown is 220V, it proves to be the live wire. If the maximum voltage shown is 12V or 36V, it proves to be the neutral wire.
Inductive Breakpoint Test Pen: The main function of the breakpoint test pen is to find the position of the internal breakpoint in the circuit after the wire is not energized. To distinguish between the live wire and the neutral wire with the breakpoint test pen, measure the live wire and the neutral wire respectively with it. When measuring the live wire with the breakpoint test pen, the sound it makes is relatively rapid, while when measuring the neutral wire, the sound is relatively slow.
Methods of Distinguishing between the Live Wire and the Neutral Wire with a Multimeter
A multimeter has an AC voltage range, which can be used to measure the voltage of an alternating current. When measuring the voltage, place the red and black test leads on the live wire and the neutral wire respectively, and the voltage will be displayed. However, when measuring the voltage, it is necessary to set the multimeter to an appropriate range. For example, when measuring the household voltage of 220V or 380V, the multimeter should be set to the AC voltage range of 700V.
The AC voltage range of the multimeter can not only measure the voltage but also distinguish between the live wire and the neutral wire, although many people are not aware of this. To distinguish between the live wire and the neutral wire with a multimeter, set the multimeter to the AC voltage range, place the black test lead aside, and use the red test lead to measure the live wire and the neutral wire respectively. Observe the numbers on the multimeter. The wire with the larger number is the live wire, and the one with the smaller number is the neutral wire. If the numbers don't seem obvious, you can adjust the range to a smaller one, and then the numbers will be more distinct.
