Any electrcians around?

I'm at the wiring stage of my new shop. On dedicated circuits with say a 20 amp welder or compressor, what size wire should I use from the sub panel to the outlet? One rated for 20, 25, 30, 40 or say 50 amps. Also, what amp breaker should be used, the same amp as the tool? I have no problem using smaller gauge wire, but how much is too much? Thanks, Bob.

Everything in my shop with excpetion of the runs out to the individual lights is 12 gauge. The light runs are 14. 12 should be plenty for a dedicated tool like a 110V compressor or a 110V welder. If you get over 20 amps, you'll need to look at the tool rating and do some research. 10 gauge is usually run for things like dryers and medium A/C units up to 30 amps on 220. Something big will usually be 220 anyway. (You know, 220, 221 - whatever it takes.) Using too big a wire is just wasted $, not really extra safety. You can also get a good book or a copy of the Nat'l Electrical Code. I have an older version of this book and it's excellent:

http://www.amazon.com/exec/obidos/tg...ce&s=books

The overcurrent device should be the same rating as the circut - or less. Most of my breakers are 15.
[addsig]

Ckelly is pretty much dead on.I've been an electrician for 12 years.#14 is good for 15amps #12=20a #10=30a #8=40a.You really wont have anything in your garage any bigger than these wire sizes will handle.Most everything that is electrical will have a plate or sticker on it telling how much it draws at what voltage.Also anything that runs on 110 will draw half on 220v.add up the amperage on a given circuit and it will tell you what size circuit you need.This is all pretty basic stuff that I have said here.If you have any Questions or need help hooking something up just email me @ mustang68stang@aol.com .
Bob
[addsig]

i will disagree with ckelly on one point, using an 8 gauge wire where a 10 gauge will work fine is extra money that need not be spent, but there is an extra safety margin there, as the load capacity of the larger wire means the wire can handle more current, thus more heat and wont burn as quickly as the smaller wire will.
[addsig]

I understand what you are saying but if that "EXTRA" safety margin is not needed why spend the extra money.If the load calculations are done right the first time there will be absolutely no problems with the system.[img]/phpBB/images/smiles/icon_confused.gif[/img]
Bob
[addsig]

[img]/phpBB/images/smiles/icon_cool.gif[/img]i agree for the most part, but i tend to be a "code +" kind of guy.
[addsig]

Thats fine whatever you feel mor comfortable with.[img]/phpBB/images/smiles/icon_rolleyes.gif[/img]
Bob
[addsig]