Wires are carriers for transmitting electrical signals and currents. They are mainly composed of insulation and wires. Different specifications of wires correspond to different insulation materials and copper wire structures. The evaluation parameters of the wire mainly include the diameter of the copper wire, the number of wires, the thickness of the insulation and the outer diameter of the conductor. In order to reduce the interference of different signals in the transmission process, twisted pairs and shielded wires are also used in automobiles. Due to the large amount of wires used on the vehicle, in order to facilitate the production of the wiring harness and the after-sales maintenance of the whole vehicle, the insulating skin will generally be set in different colors to distinguish.