Shop wiring

CThurmond

CThurmond

Well-Known Member
Joined
Aug 6, 2010
Location
china grove nc
Been building my shop and the time has come to add power to the building

Right now the shop is 18x25 x11

I want to run my 180amp lincoln welder
A 220v 2 post lift , a 5 hp air compressor.

And maybe 2 fans (30 inch wall mount and 24 inch wall mount fan)

I have 200 amp service on the outside wall of my house. I would like to run a 100 amp panel (as I already have one , indoor 100 amp Siemens) in the shop.

The shop is 75 ft from the box on my house. Going to bury the line underground. How deep?
In conduit

Trying to figure out if #2 mobile home feeder wire rated for 90 amps is going to work or not.

Or if I need to go 2/0 feeder wire rated for 150 amp

If you see any details I may have thought out wrong let me know

Any professional opinions would be greatly appreciated. Thanks

Cory T.

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If you want a 100 amp panel, then you definitely do not want to use wire rated for only 90 amp.
ALWAYS better to have your wire over rated than your needs, and certainly higher than the rating of everything it connects.

Since I'm sure you're doing this under permit from the county :D, you can always call the inspector and ask them what they like to see... since they are going to sign off on it anyway
 
Apparantly I was misinformed and I only have 100 or 125 amp service on my house.

So I guess I need to call Duke and find out what I need to do to get enough service.

And i called the inspector and told me to call an electrician and have them quote me. Which is what I'm doing but I also reached out here. I figured one or two of you may have a shop......



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Its a dangerous game to try and give electrical advice over the internet without seeing the components. Because terminology can get mixed up and cause well intended info to be inaccurate.

Regarding conductors.
#2 aluminum RHW/THHW/THW/THWN/XHHW/USE is rated for 90A at a 75 degree Celsius rise . Im going to assume that is what you have.

If you put a 90A breaker feeding the sub panel and used that wire you would be ok. You wouldnt get a true 100A sub feed but 90 is pretty close.

When you say you only have a 100A or 125A service..Im curious if thats the service rating or the rating of your main panel.

Im reciprocated in NC but dont do much (any) there. In SC as a home owner you have the right to pull electrical permits and do the work on your own home without a license, depending on scope and this would fall under approved scope.

But down here Ive never seen a 100 or 125A service. Not saying they dont exist, as I dont do much resi work.
 
I'm not 100% sure what it is, I'm going off of what an electrician said looking at my panels. I own this house so I want this to be done 110% correctly.

I called Duke but they cant confirm my service until business hours.

Right now I'm looking into replacing my main panels on house to 200 amp and it sounds like I need to go with the 150 amp wire for the 100 amp panel

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Yes no. If you kill the breaker, the attaching points for the wire are dead but the bus bars are still hot. You can swap a breaker without turning the feed off, just don't touch/get into the bus bars at the back of the panel.
 
I would personally use this opportunity to correct and modernize a few problems.

Especially if you are having to have duke pull a new service. Get a 200A meter socket without an attached panel and a separate 200A Main NEMA 3R Panel and get all those loads into that new panel, while also giving you breaker room for your shop expansion.

You are talking maybe $250 in material? And a couple hours work.
 
Ron said:
I would personally use this opportunity to correct and modernize a few problems.

Especially if you are having to have duke pull a new service. Get a 200A meter socket without an attached panel and a separate 200A Main NEMA 3R Panel and get all those loads into that new panel, while also giving you breaker room for your shop expansion.

You are talking maybe $250 in material? And a couple hours work.
Click to expand...

Or 200a meter base with integral service entrance panel. Run two breakers off that - one to the shop, one to the house panel. I like those because you can kill the entire system right at the meter.
 
10 4 that's what I was thinking Ron seems like a lot of outdated parts being used right now...

I'll get an electrician out here next week

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