The distribution cabinet is in the form of three-phase and four-wire power supply, and the standard phase sequence arrangement from left to right should be: phase A-color code is yellow, phase B-color code is green, phase C-color code is red, and zero line is blue. The yellow, green and red lines are all fire lines. The voltage between any two of them is 380 volts, and the voltage between any one of them and the blue zero line is 220 volts. The grounding wire is a green/yellow alternating line.
Extended data:
Color meaning: black, white, green, red, blue, orange, brown and gray. The color of the outer insulation sheath of the wire usually has its own reference significance. Therefore, when playing with new lights, besides turning off the circuit breaker, you should also determine what each colored wire you will encounter next means.
At first, there was no systematic color coding of residential electricity in the United States, or even a set of standards for correct use. Shortly after Edison first invented the electric light in 1879, the insurance industry began to issue some safety guidelines. The first set of formal guidelines appeared in 188 1, including addressing capacity, insulation and installation. But the wire colors are not classified.
In 1882, the National Fire Insurers Committee (NBFU) of the United States also passed the early safety regulations. 1893, the national insurance electric power association began to try to unify the different codes and specifications of electrical devices in various States, and put forward the national coding standards for electric lamps and power supply devices for building wiring.
The first National Electrical Code (NEC) was put forward by NBFU in 1897, which also ignored the standardization of wire color. Later 1928, NEC was updated and revised. One of the requirements is to establish the specification of grounding wire color, which is later white or natural gray. It is also forbidden to use these colors for live and neutral wires.
Further color coding is a new version introduced by NEC in 1937, which uses color coding lines and "multi-branch circuits" and specifies that the lines of three-branch circuits are black, red and white. More branches can add other colors, such as yellow and blue.
In 1953, NEC changed the color of grounding wire to green or bare wire. Circuit wires (such as live wires and neutral wires) are also forbidden to be green.
The version of 197 1 of NEC gives the color multi-branch coding a duel. Although white, natural gray, green and yellow-green stripes remain, these colors are also prohibited from being used for grounding wires. This specification loses the hard color coding requirement for access lines, because there are not enough colors to distinguish systems, voltages and circuits.
A few days ago in the United States, the ground wire was green, yellow-green striped or bare, the neutral wire should be white or gray, and the circuit wire may be black, red, blue, yellow, orange or yellow, depending on the voltage.
These color codes are all American, and the codes in other countries are different (Canada and the United States are very similar). For example, the colors of grounding wires in Australia, New Zealand and the United States are the same, and their neutral wires are blue or black. And the live wire can be any color except the ground wire and neutral wire. Red and brown are recommended for single-phase wires, and red, white and blue are recommended for multi-phase fire wires.
The latest change in Britain (2004) is the system conforming to the International Electrotechnical Commission (EC). Their ground color (yellow-green stripes) remains unchanged, and the neutral color changes from black to blue. Similarly, single-phase wires used to be red, but now they are brown. In addition, the marks and colors of British multiphase lines have also changed: L 1 changed from red to brown, L2 changed from yellow to black, and L3 changed from blue to gray.
References:
Baidu encyclopedia-electric wire