Red fire wire, blue zero wire, yellow-green double-color ground wire
If the colors are indistinguishable, please look down.
In practical application, I will give you three wires, one is the live wire, the other is the zero wire, and the other is the ground wire, if the three wires are the same color! How can you tell the difference?
1, the correct connection is: the phase line (L) is generally red or brown; Zero line (n) The zero line is blue or green; The color of protective ground wire (PE) must be yellow and green.
2. Can you use a clamp ammeter to measure the fire line with an electric pen? The current of the phase wire (live wire) and the neutral wire is the same, and there is no current in the ground wire under normal conditions.
3. Current flows through the neutral line; The ground wire is used for protection, and there is no current during normal operation, only when there is short circuit and leakage. It is required that the grounding resistance is very small, and the equipment end is generally protected by the shell.
Measure the fire line with an electric pen, and place the test lamp (with bulb) on one of the fire line and the other two lines. If the light is on, it means line 0. Whether the light is on or not. It means ground wire. (When the grounding wire is not grounded, the lamp test method is effective. If the ground wire is connected to the earth, no matter which wire is connected, the light will be on. )
It should not be difficult to find the live wire when there is power supply, but it is difficult to distinguish the zero line from the ground wire. Theoretically, the voltage between live wire and neutral wire is about 220 to the right, and the voltage between live wire and ground wire is about 190 volts. If you connect an energy-saving lamp, you should be able to see the brightness The bright nature is the zero line, for reference only.
5. There is a simple method.
We use a test lamp (with a bulb) to put it on the live wire and one of the other two wires. If the light is on, it means the zero line. If the light is on, the leakage switch will trip. It means ground wire.