According to the voltage loss or safe carrying, capacity selection can withstand 600 or so. According to the economic current density can be chosen to withstand about 400.

The selection of the conductor principle:

1) close by heating conditions of conductor section (safety)

2) distance based on safe carrying capacity on the conductor section selection according to the voltage loss conditions, to ensure that the load point voltage is in the range of

3) qualified; load according to economic current density.

Wire safety?

In order to ensure the current density of wire long-time continuous operation is allowed by the said safe carrying capacity.

The general rule is 5 ~ 8A / mm2 copper wire; 3 ~ 5A / mm2.

The comprehensive factors of safe carrying capacity according to the core wire usage environment limit temperature, cooling conditions, installation conditions, etc. In general, short distance, small area, good heat dissipation, low temperature, strong ability to conduct wire, and safety selection limit. long-distance, large cross-sectional area, the heat is not good, high temperature, poor natural environment, the weak ability to conduct wire, safe selection such as electrical limit; strong in ability, bare wire insulated wire, overhead line cable, cable buried in laying on the ground cable, etc.

The economic current density, the calculation is complex, generally directed by the national standard: annual maximum load hours less than 3000 aluminum copper cable 2.5A/mm cable 1.92A/mm cable 1.73A/mm cable 3000~5000, aluminum copper 2.25A/mm, more than 5000 aluminum cable 1.54A/mm 2.00A/mm copper cable, overhead line within 3000 1.65A/mm aluminum copper 3.00A/mm.