How much power for shop?

TLR

TLR

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Oct 5, 1998
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I just put in an offer on a house that comes with a 30x40' metal building. The building at this point has no power to it.

Option 1 is I could replace the line and panel to the house (which probably needs upgraded anyway being only 100amps) and run a line off to the shop with a sub panel.

Option 2 is I could have a separate meter and panel run at the shop.

So so I know you can never have to much power but which is a better economical option. Having a new meter is an automatic $30 per month charge on the bill. How much power do I realistically need?

Currently my compressor and 2x72 are the largest load items I have. At some point I'd love to build a forge and then who knows if I ever come across a lathe or power hammer...

Thanks
 
Option 1 makes sense to me



Normally you need enough power to run everything, but in a one man shop code allows for the fact you probably can't run every thing at once by yourself



What do you expect to run ?

A welder is usually a 50 or 60 amp plug

What's your compressor ? you can probably count on it running while the other stuff does
A HT oven
lighting

Lathes and mills are usually 5 HP or less unless its hugeish.



If you upgrade to a 200 amp, then a 100 amp subpanel in the shop make sense to me.
 
100 amp minimum. If you plan to use machinery, decent sized welders etc, you may be kicking yourself in the ass later for not going ahead with a 200 amp dedicated panel.


All depends on what you do and use of course, but if you've got plans for big equipment, be prepared. When you start running large phase converters or transformers you start eating up your amperage, however 95% of makers get by with 100amp or less.
 
Just a thought that buzzed through my head.

Realistically I'm not looking to sell a large volume of knives. I have a 60 hour a week job I love and have no plans to replace. If I do set up my knife making as a small business is it important to have a separate meter for financial/tax purposes?
 
TLR said:
Just a thought that buzzed through my head.

Realistically I'm not looking to sell a large volume of knives. I have a 60 hour a week job I love and have no plans to replace. If I do set up my knife making as a small business is it important to have a separate meter for financial/tax purposes?
Click to expand...

This is true for Canadian Tax, but I suspect your us is similar


No separate meter.
You pro rate the mortgage, heat hydro water and taxes based on the ratio of square footage used in business vs total square footage

I'd take that extra thirty dollar charge and put it in my pocket, call it a new tool fund.
 
Get a quote for a panel change out. Chances are you may open up a can of worms, depending on what your local codes call for. Then see how much it would cost to run a line from your new panel to the shop. Break it down to see how long at 30.00 a month it would take to spend that same amount. In the long run, it may be more economical to get a separate meter installed.
 
I have a 200 amp service to my home and a separate 200 amp service to my garage. After many years of usage the utility notified me they should have been charging me about twice the rate on the second meter the entire time. If I had to do it over I would simply run a 100 amp line from the house to a garage subpanel, eliminating the double (and spendier) basic charge for the second meter and the more expensive power.
 
I have two 200 amp panels in my house and one 200 amp panel in my shop. Both services are read through an inductive loop (the same loop) and are accounted on the same meter. Think about checking with your provider to see if the meter can be changed to an inductive loop type. Jess
 
I have a two man shop 32 X 24 with 4 grinders, welders, two cnc mills and all the rest. I ran a line to the shop off my main 200 amp panel with a hundred amp main and single breaker slots in the shop. It's worked well for 5 years with no line overload.
If you are going to run off your 200 amp main panel don't put a second ground wire off the panel in the shop.
 
Thanks everyone. I appreciate all the info and advice. I'm going to have a talk with an electrician and see what my options are based on local codes. It sounds like 100 amps should be sufficient for the shop based on my expectations for what I want to do.

Fred can I ask why the advice against the secondary ground?
 
TLR said:
Thanks everyone. I appreciate all the info and advice. I'm going to have a talk with an electrician and see what my options are based on local codes. It sounds like 100 amps should be sufficient for the shop based on my expectations for what I want to do.

Fred can I ask why the advice against the secondary ground?
Click to expand...

It makes for a closed circuit, if some thing shorts in the shop and you have two copper grounds with cable running off both panels, there is a direct path for between the two underground. If you have the ground coming off the main panel a short in the shop will go directly back to the main panel and discharge there. I at one time had the shop panel wired with its own ground; a good friend, who wires for AEP told me the above. After thinking about it; made sense to me.

Fred
 
Excellent. Thanks for the reply. It does make sense but I had never thought about it.
 
I just upgraded the 100 amp service in my new 30x40 to a 200 amp service. 100 amps wouldn't run everything.
 
100 amps would not be enough for me either. My shop is 30x40 ( self built and wired) and has 2 x 15a, 120v circuits, 8 x 20a, 120v circuits and 3 x 50a, 220v circuits. The wall I thought would be dedicated hotrod parking is now where my grinder is. I wish I had put another circuit there. Goes to show that just enough is never quite enough. Jess
 
I have a single 50 amp welder outlet in the shop, and I have my dryer outlet in the basement about 30 feet from the shop (walk out basement) between the two, I have put 50 amp welder plugs on all my 220v tools, and made an adapter cable for the dryer outlet -> 50amp welder outlet.

I find that I'm rarely ever using more than 1 220v appliance at once anyways, so with access to 2 outlets, i'm usually just fine.
 
Oh, I should add that there are 2 20 amp 110 circuits in the garage, the 50 amp welder outlet is just the only 220 run to the garage, so i'm really closer to 100 amps total service in the garage, but half of that is for my 220.
 
Can you run a second leg off of the meter? That may do the trick.
 
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