Originally Posted by
Goldenrivett
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Wire needs the same dimensions to carry the same current - whether its AC or DC. The heating effect is I squared * R - doesn't make any difference to the direction of electrons.
At low voltages, large DC currents must be carried by larger, heavier wires. The associated components are also heavier, so weight becomes a major disadvantage. Higher voltage AC is more practical with its light weight components. High voltage AC power is preferred over DC for large aircraft mainly due to weight and space savings and low current transmission. AC generators are lighter and smaller than DC generators of a similar output.