What Size Wire For 40 Foot Run To Shop From Main Panel To Add 220 To My New Shop?

John Caven

John Caven

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Ok so i just got a lathe and a mill and am building a new shop. What size wiring do I need? I've done normal home wiring but I'm not sure the size for a job like this. I plan to use a rotary converter!
 
First, you need to decide the amperage required/desired in your new shop. It's difficult to have too much power available. The wire is sized to carry the amperage over the distance. It's called ampere capacity (or ampacity for short). Easily Googled.

Also involved is the viability of the source of the power. If you plan to run a 50 amp subpanel from the ancient 100 amp panel on the house, you may start browning out the house.

More information is needed about your circumstances to provide an intelligent answer.
 
John Caven said:
Ok so i just got a lathe and a mill and am building a new shop. What size wiring do I need? I've done normal home wiring but I'm not sure the size for a job like this. I plan to use a rotary converter!
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I have found wiring guides on the net(google) just enter the numbers and the length of the run and it will calculate wire size for you.
 
The 40' length is not going to be a concern. What is the amperage or current of the equipment that you plan to run in your shop?
 
Always better to have too much than too little capacity , but consider how many machines/appliances will be running at the same time, that's the main consideration.
I ran #6 copper 40' +- to a new sub panel in my garage/shop a couple yrs ago, probably over kill as I most likely will never come close to using the full load capacity at the same time.
The largest "power user" is a 50amp ac/dc welder.

Brian

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Allow for the largest machine you'll ever run + lighting.
Not likely you'll ever have a mill, lathe , compressor, welder, running at the same time.
I ran # 2 CU 60 feet to a 100 amp panel. Way more than I'll ever need, but I'll never have to dig it up to go to a larger wire size either
 
If you are running conduit, bury a few extra 3/4's. You may want to add switches and stuff


Sent from my iPhone using Tapatalk
 
"The largest "power user" is a 50amp ac/dc welder."

Forgot to add that's running at max capacity, won't ever need to use it that way, not a ship yard, just a small shop.

Brian
 
how much is 40 feet of # 2? I'm trying to find the best place to buy cable. I too like overkill :)
 
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