- Joined Oct 3, 2010
I am thinking (watch out). If I want to move lots of amps (think, hundreds of amps) then I need a big fat wire. But I don't have a big fat wire. I have a lots of 12 & 14 AWG wire though. Could I not run multiple smaller wire to achieve the same current capacity? NEC says I can (see attached) but anything over 4 wires has to be derated according to the table. I want to carry 500A, but NEC says max amps for 14AWG is 25A, so I would need 20 in parallel. The derating is 50% for 20 in parallel, so I need 40 in parallel. But, 40 in parallel puts me into the next level of derating - not sure if I'm supposed to take it a step further. That seems ludicrous to me. 40 wires in parallel? really? I need to know how to calculate how much a wire can carry, vise what NEC thinks is safe to carry in a residential installation. And where is this derating coming from? What is the reason for that? I fancy that the wires would share the current quite well without derating. How many 14AWG wire would I need in parallel to carry 500A? How do I calculate that? and what's a good rule of thumb for buffer room on the that?
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