Generally speaking, the colors of three-phase wires are yellow, green, and red, which are A, B, and C phases respectively. Blue is the neutral wire, and the yellow green alternating wire is the grounding wire. When wiring, the yellow, green, and red grounding wires, blue is the neutral wire, and the yellow green alternating wire is connected to the PE protection wire or to the equipment casing (which is already connected to the ground grid). Sometimes when the color distinction between the four wires is not very clear, the three wires with the same cross-section are the live wire, and the wire with a slightly smaller cross-section is the neutral wire. The transformer you mentioned may be the power supply for the control circuit, such as 380V, connected to any two live wires; If it is 220V, connect one live wire and one neutral wire.

The actual operational safety is that red is the live wire, blue is the neutral wire, and yellow or yellow white is the ground wire. The phase lines are generally yellow, green, and red, the protective neutral line (PEN line) is black, and the protective line (PE line) is a yellow green dual color line. The protective line is strictly prohibited from being used as a phase line under any circumstances.

According to Article 16.1.4 of the Construction Code for Residential Decoration and Renovation Engineering GB50327-200116.1.4, "When wiring, the colors of the phase line and neutral line should be different; the color of the phase line (L) in the same residential building should be uniform, the neutral line (N) should be blue, and the protective line (PE) must be yellow green dual color line.

According to the regulations, it can be concluded that the protective wire (PE), which is the ground wire, must use a yellow green dual color wire (mandatory requirement), the neutral wire must use a blue color wire (not mandatory requirement, blue wire should be selected when conditions permit), and the phase wire must use red, yellow, and green colors if blue is not used. (The color of the phase line has not been consistent yet, and different companies may have different regulations. The following color scheme can be used as a reference. The neutral line should be uniformly blue, and if used for sockets, the phase line should be red. The incoming line of the light path should be red, and the control line or dual control line of the light path should be yellow and green.) According to the specified color wiring socket diagram: red, blue, and dual color lines should be threaded into the socket bottom box. Red is the live wire, blue is the neutral wire, and dual color wire is the ground wire. Thread the wires according to the specified color, which is also convenient for construction. Connect the red live wire to the L pole of the socket, connect the blue neutral wire to the N pole, and connect the two-color wire to the grounding label.

According to the specified color light wiring diagram: red for incoming wires, blue for neutral wires, and yellow for control wires (green can also be used).