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nornbartel

Need Help Sizing Wire to Run from Outdoor Submain to a Building

Norn Bartel
7 years ago

I need some
help determining what type of electrical service wire I can/should run in
underground 1 ¼” grey plastic conduit (buried 2 feet deep) from an outdoor
submain split-phase 120/240 volt breaker box (50 to 60 amp breaker) to a
building. From outdoor breaker box to indoor
breaker box it will be right at 75 feet of wire. The purpose is to power a 1 HP 240 volt electric
submersible pump (another 50 feet away & 150 feet depth), power a few
lights in the building and I might also add a hot water heater and a couple of
½ to ¾ HP electric drive pumps in the future.
I’d like to run 4 gauge wire in case I add more load (like a welder) but
perhaps 6 gauge is enough. I’m not
sure. The main thing I need help with is
determining what type of wire to use.
I’d like to run a jacketed 3 wire cable (4wire with ground wire) but
perhaps three individual wires (two black, one white) would be fine. I don’t believe that I need direct bury “UF-B” type round cable since it will be in
glued, grey conduit and not be exposed to light or weather. I can only find it up to 6 gauge & flat. Not sure if I should just use single
“THHN/THWN wires? I’d rather not. As background is a farm/ranch
application. My place is over 30 miles
from the nearest small town so having an electrician is not really an
option. If it is to be it is up to me
when you’re that far out. Any advice,
recommendations would be appreciated.
Also a supplier would be helpful.

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