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wtdboss01 04-17-2008 04:14 PM

House to Barn wiring job
I just recently moved into this house on 9 acres and I need to put power out to my barn that is 300' down the driveway from the house. I used a voltage calculator to determine wire size and it is telling me that I need #2 copper for 120 volt, 30 amp, at 300' distance. I was planning on digging a trench and laying in 2" Sch 40 conduit and running the 2 wires
(1 hot, 1 neutral) down there as well as driving a grounding rod in next to the barn and installing a 30amp sub-panel. At today's copper prices though that is gonna get very expensive. Is there a better way to accomplish what I'm trying to do?? The barn is doubling as my workshop and will have a 120volt 5hp air-compressor, as well power tools and lights running in it. Any ideas anyone has here will be greatly appreciated.


Ps: I have 25yrs in the building materials industry with several of those as a carpenter in construction so I have a basic knowledge but am not an electrician.

triple D 04-17-2008 10:04 PM

scratch the copper!
Well if I were asked, I would say you should run 2 hots a neutral and a ground, as opposed to a single 120v feeder. Is it possible to just put a seperate service and meter on shop? If not, than you could run an aluminum 2ot urd./with a #4ground wire (also aluminum). This will allow for 100amps easily. And is fairly inexpensive. And yes you are correct you should also have a ground rod for out building service. Copper is just not necessary in this case. Good luck, and welcome!

speedy petey 04-18-2008 03:37 PM

I agree, a 30A/120v sub-panel is simply crazy. Especially at 300'.

I also agree that a run of 1/0AL to a 100A sub would be your best bet. You could go smaller (amperage wise), but the ONLY thing you would be saving money on would be the wire, and that would be a minimal savings.

kok328 04-18-2008 03:58 PM

He's running 300ft., should it be 1ot or 2ot?

Definetly SE cable not copper.

triple D 04-19-2008 11:51 AM

1ot would probably work with min. load at 300'. But 2ot may be cheaper, or if not, can sometimes be more readily available. But why stretch it, with 2ot your way safe. Good luck again my friend.....

speedy petey 04-19-2008 02:09 PM

Even with 1/0 he is way safe. Why spend the money if you don't have to?

It's easy to say bigger is always better, but it is not always necessary.

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