Check out some similar questions!

whisky4 · Mar 9, 2008, 02:37 AM

Hi, this is whisky4,my question concerns running power to my shop that is 140feet from
my house.
We upgraded our incoming power to 320amps and put it underground,now we want run
power to the shop it was suggested that I put a 100amp breaker in my existing panel on

house and run 100amps to shop panel and power up everything in shop,there will be
(6) overhead florescence lights, (1) 50amp plug for welder, (2) outside lights,
(2) garage door openers, (10) wall outlets.
the shop is 40x50x12 all metal building,thank,s whisky4

donf · Mar 9, 2008, 04:04 PM

You need to make a friend out of the code book.
Where are you that you are getting 320 Amps? I thought residential tops out at 200. If you need a 50 amp line for your welder, then you probably need a four wire set up that allows 120/240 voltage and since you are talking 50 amp, then you need #6 for that run alone.

You really need to calculate the required load for the shop before going forward with any plan. Just the wattage needed for the welder would be
240 VAC* 50 Amps = 14,400 watts. See if you get get an electrician to analyse the load requirements for you.

whisky4 · Mar 9, 2008, 11:56 PM

Hi donf,here in Washington it is not too uncommon to upgrade to a 320amp service
By just putting in I believe 350mh wire under ground from transformer to a 350amp
Meter base,then bleed off what you need for other uses,thank,s whisky4

stanfortyman · Mar 10, 2008, 04:26 AM

100A to a shop like that should be OK. Depends on what you will run at the same time. A load calc is a hard thing to do with a place like that.

I would seriously consider a dedicated 200A service to the shop.

Dan, a 320/400A service is getting more and more common these days. Every place installs them.
Some of these mini-mansions are getting 600A and even 800A services.

donf · Mar 10, 2008, 07:10 AM

Stan, because of the presence of the welder and that it could generate 12,000 Watts. Nor are given the wattage on anything else I also would suggest a 240 lateral service if the power company will do that.

stanfortyman · Mar 10, 2008, 10:09 AM

ALL services from the POCO are 120/240v.

A 100A would be OK, but there is really no reason, other than maybe a couple of hundred bucks, not to go 200A. IMO a dedicated 100A service would be a big mistake.

For a sub-feed from an existing house 100a would be "adequate". For a new dedicated service, I'd want more than adequate.