Facing the socket, wiring should be made according to the correct connection of left zero (N), right fire (L) and ground (E). Fire line -L (red, yellow and green), neutral line -N (blue or black) and ground line -E (yellow and green).
Three-phase four-wire system is used to transmit power in low-voltage power grid, in which three-phase wire (live wire) represents phase A, phase B and phase C respectively, and one neutral wire (neutral wire). In order to ensure the safety of electricity consumption, the user uses three-phase five-wire system for power supply. The fifth wire is the grounding protection wire PE (ground wire), one end of which is buried in the ground near the user's area with metal conductor, and the other end is connected with the grounding contact of each user, which plays the role of grounding protection.
Grounding wire is a line that connects the equipment or electrical appliance shell with the earth reliably, and it is a good scheme to prevent electric shock accidents. Proper grounding can improve the anti-interference ability of the whole system.