What determines the current capacity of a conductor? How can I know the maximum current, any conductor can carry safely, over shot or long durations of time. Example: A conductor that is 1m long, 0.00025m wide, and about 0.003m thick is used to deliver power continuously in a system. How much power can it deliver continuously without causing any problems(fusing)? I know there is a difference if its DC or AC, how different? And if the resistance in my example is 0.3Ohms, how does that help finding the current capacity?