The maximum current capacity of 10 gauge AWG copper wire varies based on the length of the wire. For a 12-volt system, 10 AWG wire safely conducts up to 20 amps for 15 feet or up to 5 amps for 70 feet.
American Wire Gauge or Brown & Sharpe wire gauge is a standardized wire gauge system used in the United States since 1857. The system measures the diameter of electrically conducting wire using measurements based on the ASTM standard B 258. As wire gauges increase, wire diameters decrease as well as current capacity. Doubling the diameter of the wire decreases the gauge by six. For example, 2 AWG wire is twice as thick as 8 AWG wire.