(1) the wire must have sufficient strength to avoid being broken by wind, freezing or repair.
(2) long time through the load current should not make the wire overheating, in order to avoid damage to the insulation or cause the circuit to fire and so on.
(3) the line voltage loss can not be too large.
The procedure for selecting the wire cross section is as follows:
(1) Harness processing plant production of low-voltage wiring harness, the general first by the wire heat to select the wire cross-sectional area, and then use the voltage loss and mechanical strength conditions for verification.
(2) Harness processing plant production of high-voltage wiring harness, the general first by the economic current density to select the wire cross-sectional area, and then use the heat and voltage loss to test.