I need to find out how inspectors are treating this rule that all conductors need to be the same length. Is there any standard percentage length difference that they allow?

I find that if there is a 10% difference in length between two conductors, there is approximately a 10% difference in the current through each conductor, with the shorter conductor carrying the larger portion of the current.

Also, do inspectors look at the whole installation as to how important it is for conductor length to be exactly the same.

For example, if you have 2 parallel - 1/0 conductors, 75C rated 150A feeding a 300A load. If there is any difference in length between the conductors, the shorter conductor would exceed it's ampacity rating.

But, if those same two conductors are feeding a 250A load, the ampacity of the shorter conductor is not exceed until it there is over a 30% difference in wire length.

Can anyone help me here?

Thanks,

Laura Jenkins
IBEW 48