How to divide the wire into neutral wire and live wire with electric pen and multimeter
The first method is to use an electric pen to distinguish the neutral and live wires:
It is the simplest test method to distinguish the live wire and the neutral wire with an electroscope pen, just observe the indicator light;
Use an ordinary electroscope pen, that is, the one with an indicator light. When using it, you must follow the instructions, pay attention to safety, and the wiring must be handled properly, and blind operation is not allowed;
After the two wires are energized, touch the core of the wire with an electric pen, the one with the indicator light on is the live wire, and the one with the indicator light off is the neutral wire.
The second method is to use a multimeter to distinguish live and neutral wires:
Using a multimeter to distinguish live wires and neutral wires is a little more troublesome than using an electroscope pen. Before testing, do the following work;
Before use, insert the line pen with the black meter into the COM end, which is the common port hole, and connect the red meter pen to the VO, which is the test port hole;
Then adjust the gear of the multimeter to the gear of about 750V, complete the above steps to prepare for the test;
Be sure to handle the wire ends before testing, and then turn on the power. During the test, one hand holds the red test lead to touch the core, and the other hand holds the black test lead to touch the ground or the wall. The multimeter shows that the voltage is about 220V. Fire wire, the display value is close to 0 is the zero line;
Through the above steps, we can easily distinguish which is the live wire and which is the neutral wire.
How to measure the fire wire in the line with a digital multimeter
First, turn the digital multimeter to the AC ~ 750V gear, use the red test lead line or the black test lead line of the multimeter, wrap it around your hand for 3~5 times, and insert the other test lead into or contact the metal pile head of the conductor or socket.
This is the principle that the contact between the wire and the human body will form a distributed capacitance (the more the number of conductor turns, the greater the capacitance formed with the human body), and the sensitivity of the digital multimeter itself is higher than that of the pointer multimeter. So the response to the display value of the digital multimeter is larger.
The above is a commonly used measurement method, usually wrapped around the hand 4 times, the measured result at this time is ~57V, there is no doubt that it is the live wire. The test lead line wound on the hand does not move, and then use the black test lead to touch the other ground wire N and PE protection ground respectively.
At this time, the measurement result of the digital multimeter is displayed as 000, which means that the live wire, neutral wire, and PE protective grounding in the line have all been detected.
We all know that capacitors can block DC and AC. Using this method is mainly safe, convenient, and can be used under any circumstances.
Set the digital multimeter to the AC 700v range. If you don’t know the voltage, you should switch to high-end. Use the red test pen to test one, and the black test pen to test the other two. If one is 220v and the other is ov or very low, then the red test pen The live wire is connected, and the voltage connected to the black test lead is zero or extremely low, which is the ground wire. The voltage connected to the inner pen is 220v, which is the neutral line.
