Copper used in connectors is mainly brass and bronze (the hardness of brass is slightly lower than that of bronze), with a large proportion of brass. In addition, different coatings can be selected according to different needs.

(1) Selection of wire type

Harness design and harness type selection are the environment and function of the harness. For example, the ambient temperature around the engine is very high, and there are many corrosive gases and liquids. Therefore, high temperature, oil, vibration and friction resistant conductors must be used; The steel wire on the luggage compartment cover must maintain its elasticity at low temperature, so cold elastic steel wire must be used to ensure normal operation; The wire on the automatic transmission shall be resistant to high temperature and hydraulic fluid, and its temperature stability shall be good; Shielded wire shall be used for weak signal sensor, such as knock sensor, crankshaft position sensor, ABS wheel speed sensor, etc; The interior line of the door requires high bending resistance.

The wires commonly used in automobile harnesses are usually multi strand copper wires, and PVC insulation materials are used for insulation. The wires used in the harness shall have the characteristics of temperature resistance, oil resistance, abrasion resistance, water resistance, corrosion resistance, oxidation resistance, flame retardancy, etc.

The commonly used harness types of automobile harness include Japanese standard (AVSS, etc.), national standard (QVR), German standard (FLRY), American standard and other major series. AVSS (AVS) cable is characterized by thin insulation and good flexibility; QVR is characterized by thick insulation layer, relatively soft and good ductility; German standard wire insulation is thinner and more flexible; American standard wire insulation materials are generally thermoplastic or thermosetting elastomers, and those that have been irradiated. Suitable wire types can be selected according to the needs of users and different working environments.

(2) Calculate and select the cross-sectional area of the wire

Calculate the current flowing through the wire according to the power of the electrical device; Long term electrical equipment can use wires with 60% actual bearing capacity; For electrical equipment with short working time, wires with actual bearing capacity of 60% - 100% can be selected.

The cross-sectional area of the conductor shall be appropriately changed according to different working conditions and temperatures.

The cross-sectional area of the wire shall be appropriately changed according to the direction of the wire and the number of connectors (i.e. the size of the voltage drop).