Quote:
Originally Posted by markdoane
I wouldn't run the aluminum inside the dwelling, so I would just measure the trench length and add 7 feet at each end (18 inches deep + 48" above ground + 18" in the box).
I would use copper in the crawl space, but you're the homeowner.
And I thought we were using #2 AWG, not 2/0?
|
#2 AWG is appropriate per the NEC, but there would be high voltage drop at 80A (I think around 4-5% if memory serves). Upsizing to 2/0 keeps the voltage drop to under 3% at max current. This is assuming a 0.9 power factor. Probably a bit over-engineered but not excessive in additional cost.
I would actually be more concerned about having a splice in the wire than aluminum wire in conduit inside the building. My concern may be misplaced, but I think the splice would increase any risk. The wire's insulation is rated to 90C but the max ampacity at 60C (115A) is well over the 80A circuit breaker - so the possibility of overheating is very small.