[TCML] Wire Gauge

[David Dean]

On Friday 30 May 2008 03:46:17 pm G Hunter wrote:
> For an outdoor 240vac/40A hookup, is 8AWG big enough, or should I go with
> 6AWG?  The cable run will be roughly 100'.
>
> Thx,
>
> Greg

Hi

Assuming copper conductor and THHN insulation the Ampacity would be OK, though 
you would be near the limit for 2% voltage drop. If you can live with the 
voltage drop at or near 2% (maybe closer to 2.5%) then 8AWG is OK. Keeping in 
mind that the new code requires a full size ground for 6AWG and smaller, and 
if you are going to pull a neutral, you are looking at 400' of wire. Though 
6AWG would be better, with the price of copper now days, price may well be 
the deciding factor.

later
deano