In daily use, it will determine the line, zero, and ground wire according to the color of the wire. If the five cores are used, the color of the wire is yellow, green, red, blue, and two -color lines, and it is very good to distinguish between fire lines, zero lines, and ground wires. According to the standards of the national regulations, yellow, green, and red are used as three -phase fire line, blue lines are used as zero lines, and dual -color lines are used as ground wires. The unified standards can be achieved in the use of the national standard line color cable.

National standard line color wire

However, in daily use, the colors in the protective lines and cables are all diverse. Which line color is a lot of controversy and no fixed standards.

2 × 1.5m㎡ protective cover

Two -core protective line

Two -core sheaths are usually connected to 220V voltage, one connects the fire line, and the other is connected to the zero line. If it is a red thread and a blue wire, it is easy to determine which line color is used as a fire line and which root line color. As a zero line.


When the two -core protective kit is a blue line and a black line, how to determine the line and the zero line! I usually use black as a line of fire and blue as a zero line.

And my colleagues are usually blue as a line and black as a zero line. The two of us are controversial in this regard. No one persuades anyone. They do things with their respective standards.

I also checked it also,

Blue is the standard line color of the scratch line in my country. Black is the international zero -line standard line color.

In my inner feelings, in our country’s land, it is great to be based on our country’s standards.

5 × 2.5m㎡ protective cover

Five -core care set

The five cores are yellow, blue, red, black, and two -color. I usually use yellow, red, and black as a three -phase fire line, blue as the zero line, and the two -color line as the ground line.

And my colleagues are usually yellow, blue, and red as the three -phase fire line, black as the zero line, and the two -color line as the ground line.

It is also the blue line as the zero line, or the black line is controversial on the zero line. However, on some devices, the above five line -colored nursing wilows are also more likely to be used as a zero line.


Is it in the protective set and when there is blue and black lines at the same time, the black line is used as a zero line, is it more standard?

Essence Those who have different opinions can be guided below.


4 × 2.5m㎡ cable

4 core cable

4 -core cable, the line color is red, green, blue, and dual -color. When the power supply is a ground line, a three -phase fire line is not required. There are usually no controversy. Red, green and blue fire lines, two -color line ground line.

When the power supply equipment requires the zero line, the three -phase and four -wire power supply. How to allocate the four colors, usually the two -color line is connected to the zero line.

The blue, green, and dual -color line fire lines are relatively small. How do you use it!

3 × 2.5m㎡+2 × 1.5m㎡ cable

Five -core cable

When the five -core cable is formed by three 2.5 square meters+two 1.5 square meters. The cross -sectional area of ​​the three -phase fire wire wire must be consistent, and the level of the cross -sectional area of ​​the wire must be greater than the line color level. The zero line and the ground line can be lower than the cross -sectional area of ​​the three -phase fire line.

Three 2.5 square meters of black, red, and blue fire lines, 1.5 black lines connect to the zero line, and the two -color line ground wire. Although there are two black lines and one blue line, there are no controversy in daily use.


When connecting the power supply, if the device comes with a power cord, it must be based on the other end of the power cord.

When the device is not equipped with a power cord and requires an external wiring, the selected cables are the same section of the cable. At the same time, there are blue lines and black wires. The wires of which color you choose to choose is more standard. Welcome to discuss below.