In this age of electrical appliances, wires have become ubiquitous in our lives. Everyone knows that each wire is marked with a different color, but many people are unfamiliar with what the wire colors represent. Household electricity is generally three-phase, yet many people are still unfamiliar with the colors of the three-phase wires and don't know what each wire represents. Today, I'll share with you what wire colors represent.
What do wire colors represent?
Generally speaking: Three-phase wires are yellow, green, and red, representing phases A, B, and C. Blue is the neutral wire, and the alternating yellow and green wire is the ground wire. When wiring, the yellow, green, and red wires connect to the live wire, blue to the neutral wire, and the alternating yellow and green wire connects to the PE protective conductor or to the equipment casing (which is already connected to the ground grid). Sometimes, when the four wires' colors are unclear, the three wires with the same cross-section are the live wires, and the slightly smaller cross-section is the neutral wire. The transformer you're referring to may be the power supply for the control circuit. If it's 380V, connect it to any two live wires; if it's 220V, connect one live wire and one neutral wire.
In practice, safety comes first. Red is the live wire, blue is the neutral wire, and yellow or alternating yellow and white is the ground wire. Phase wires are generally yellow, green, and red. The protective neutral wire (PEN) is black, and the protective conductor (PE) is a yellow-green two-color wire. Under no circumstances should the protective conductor be used as a phase wire.
According to Section 16.1.4 of the "Construction Specifications for Residential Decoration and Renovation Engineering" (GB 50327-2001):
"When wiring, the phase and neutral wires should be different colors. The phase wire (L) within a residence should be uniform in color. The neutral wire (N) should preferably be blue, and the protective conductor (PE) must be a yellow-green two-color wire."
According to the specification, the protective conductor (PE), or ground wire, must (mandatorily) be a yellow-green two-color wire, while the neutral wire should be blue (not mandatory; blue should be used when conditions permit). Phase wires, if not blue, can be red, yellow, or green. (Phase wire colors haven't been standardized yet, and different companies may have different regulations. The following color scheme can be used as a reference. The neutral wire is blue. If used for a socket, the phase wire is red. The incoming light wire is red, and the control wire or dual-control wire for the light circuit is yellow and green.)
How do you wire according to the specified colors?
Schematic diagram of wiring a socket according to the specified colors: Red, blue, and two-color wires are inserted into the socket base box. Red is the live wire, blue is the neutral wire, and the two-color wire is the ground wire. Wiring according to the specified colors is also convenient for installation. The red live wire connects to the socket's left pole, the blue neutral wire connects to the north pole, and the two-color wire connects to the ground indicator.
Schematic diagram of wiring a light circuit according to the specified colors: The incoming live wire is red, the neutral wire is blue, and the control wire is yellow (green is also acceptable).
The above is a brief explanation of what wire colors represent. Connecting wires is actually relatively simple; simply connect the same colors. However, if the wires are to be connected to an appliance, it is necessary to clearly distinguish between the live and neutral wires. This requires understanding the nationally specified neutral and live wire color markings and avoiding random connections to prevent accidental injury during disassembly.
