Setting up 220 service in workshop

All of the outlets in my gargae (my workshop) are 110 on a single 20amp breaker. I would like to add some 220 outlets for my belt sander, table saw, dust collector, etc. I have an unused 40 amp double pole breaker and room for several more breakers. The questions I know to ask are listed below. I'm sure there is more to it than that. If anyone knows of any links to articles about wiring a workshop, they would be greatly appreciated. Thanks.
What guage wire do I use?
How many breakers do I need?
What amperage should they be?
How many devices can be run per breaker?
Thanks,
Bob Bowles
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The general rule is:
14 gauge for 15 amps 12 gauge for 20 amps 10 gauge for 30 amps
For long wire runs, you need to increase the sizes, but assuming the breaker box is in your garage, you should be able to reach anywhere in the garage with the above. If you're putting in 220V outlets for machines, go with all 20 amp circuits (even if the machine only requires 15). Some day you'll get a bigger machine and you'll be kicking yourself for not putting in the 20. The extra cost is trivial.

One per circuit :-) How many circuits do you need? One way to do it is to put each 220V outlet on its own circuit (this may even be required by code), but in practice, in a one-man shop you could have multiple machines sharing a single circuit because they'll never be on at the same time. You want a separate circuit for your dust collector, because that WILL be running at the same time as another machine.
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    Greetings and Salutations.     First off, I am not a licensed electrician, so these are only personal opinions...not legal guidelines.
wrote:

newsgroup. While this is not a Black Art, the most complex thing about it is that every local has its own variation on the NEC standards. The best thing to do is get a copy of the building codes from your local government, and, use them at guidelines. Remember, though, that they are the lowest common denominator so, I tend to prefer to go one step up. If, for example, the code calls for 10ga wire I will use 8ga. If it calls for plastic conduit, I will use metal.

maximum continuous amperage you are going to be pulling, and how the wires are run (Nomex, or through conduit...)

run.
the bottom line is that the breaker will have to be bigger than the MAXIMUM pulled amperage expected.

Again...this is a code issue. There may be limits as to how many sockets you can put on a single run, or, it may be an issue of how much power you are going to pull. Local codes will answer this (even if it IS in an obscure fashion).
    The bottom line is that you want to have wires, breakers and sockets set up so that the electricity will happily run through and do useful work without heating things up to a dangerous point. Electricity can be your friend, but, alas, it is a ravening beast when it gets free. You also want to be sure that the wiring is done in such a manner that it is protected from impact damage (which is a likelyhood in a shop). I believe that, because of this, code calls for wiring to be enclosed, either in a wall, or in conduit when it drops closer to the floor than 6' (I forget the exact number, but that should be close enough).
    Although an electrician is not cheap...it can be cheaper to have one come in and do the job than do it oneself, simply because it will get done quicker, and is more likely to pass inspection.     Regards     Dave Mundt
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Bob,
I and many others have gone through the same thing you are going through. For what its worth, let me tell you about my final solution and the reasons.
I ended up running a new feed to my shop to a new panel. It was fed by a branch breaker in my house main panel. Whereas this sounds like a big effort and expense, its actually no more effort and expense than running just a circuit or two from your existing panel. Its amazing how cheap a new panel with a few breakers is. Here's a list of things I did:
1. 60 amp 2 pole branch breaker added to existing home panel to feed shop 2. #6 INDIVIDUAL stranded wires (red, white, and black) for power, #10 green stranded for ground 3. Run feeder wires to shop outside in 1" PVC conduit mounted under eave of house (garage is semi-detached) 3. New panel in shop (about $18) 4. New breakers in new panel ($6-$8 each)
The total parts cost was between $150-$200.
Individual wires are cheaper and much easier to deal with.
If you do this, you will pat yourself on the back every day for the next two years. For a one person shop, this scheme will run just about anything you can throw at it. Those who have ample power to their shops smile every time the table saw, dust collector, lights, and compressor are all running at the same time.
As to books, I highly recommend "setting up shop" by Sandor Nagyszalancszy, published by Taunton press. Its got chapters on all the key topics that people worry about in putting a shop together. The chapter on electrical power is pretty decent with good pictures.
Bob

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12 (assuming you have nothing over 20a) unless the run is over 100', then 10. 12/2 is fine for purely 240v, but you might want to run 12/3 just in case you some day want to use it for 120v also.

One double per circuit.

20a for a 20a circuit.

Devices or outlets? As many outlets as you want; as many devices as you have power for.
The important thing is to figure out the amperage requirement for everything you will be running, and then figure out what will be run at the same time. I can run my TS (9a) and my DC (8a) together on a 20a circuit, so I only needed one. If your equipment is bigger, you might need 2 or 3. If you are getting up to 3 circuits needed it is probably just as easy to put in a subpanel, as someone else suggested; especially if your panel is crowded or far away.
240v is no more dangerous or difficult to install than 120v, but unless you are sure you know what you are doing (and having to ask these questions is not a good sign) it is best to get someone who does. There are a lot of little things that have to be done right for a safe (and legal) installation; they are not difficult, but you have to know what they are. It is also good to ask your town if they have any special requirements regarding conduit, inspections, or anything else.
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I think some codes only allow one outlet per 220v circuit.
I ignored that section in my own shop, but the information should be passed along. <G>
Barry
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On Sat, 24 Jan 2004 17:07:00 +0000, Bob Bowles wrote:

Find an electrician who will let you do all the work. Pay him for advice. Electricity is nothing to fool with. Unless you can be absolutely certain the advice you get from newsgroups is correct, you are taking chaces.
People get hurt and fires start from poor wiring jobs.
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Well I'm a qualified electonic engineer and back where I come from all the power is supplied as 240V 13amp. None of your whimpy 110v torch battery stuff for us Brits, if you don't come close to killing yourself when you electrocute yourself what is the point?
Now I am living in the US I am trying to work out what is really involved in adding some 220V outlets to the basement to power my table saw, dust collectors etc.
Would it be necessary to upgrade the power hookup to the house or is the standard supply balanced 110V 0 -110V so all the electrician has to do is stick a circuit breaker in across the 110V and -110V to get 220V?
If I turn out to need to upgrade the power hookup to the house anyway (we have several breaker panels already) what is a reasonable fee? I was quoted $3,000 which seems rather a lot to run a wire from a utility pole 20' from the house.
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snipped-for-privacy@comcast.net (Phillip Hallam-Baker) wrote:

Depends on how old your house is. I would guess anything built in the last 30-40 years or so is likely to have 220V service. Before that, maybe not.
Look in your circuit breaker box. Do you have any 220V circuits already? They typically look like two regular circuit breakers with the handles bolted/riveted together. In a single-family house, the most likely uses would be really big window air conditioners, central air, electric heat, electric stove, or electric dryer.
The real test is to open the breaker box and stick your tounge on the bus bar. If your toenails curl up, it's 110. If your belly button inverts, it's 220.

It's not just a new wire. It's a whole new breaker box. Not to mention a new meter and perhaps conduit to/from the meter.
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I was about to say that this should be attempted only by professionals, but then I recalled the story I heard about a "professional" electrician who decided to measure the voltage across the 13.8KV lines with his 600V VOM! He was lucky to be only temporarily blinded and deafened by the flash and boom that followed and the burns were minor when the test leads vaporized. The meter was a total loss...
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Standard US power is center tapped 240v. You have the right idea. 2 breakers on opposite phases gets you 240. One phase to the grounded centertap is 120.
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I can't seem to find the 240volt service in my new shop. I wired all day and the inspector even signed off on it today!! and not a 240volt service to be found in the whole place:-)
http://wacworkshop.com/html/shop_services_gallery_9.html
William....
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snipped-for-privacy@comcast.net (Phillip Hallam-Baker) wrote in

Hi Phil,
I just did the same thing, including emigrating from the uk. I found that getting a definitive answer on code related stuff is often difficult and confused here, with enough leeway left to the inspectors interpretation to make life irritating. Heres my experience in FL, it will probablt be different anywhere else..
It depends upon your local codes but usually the utility company owns the wires up to the house attachment. You own the wires from that point down into the meter and on. If you need to upgrade the panel or have work done on it then generally a contractor is necessary or someone who is registered journeyman or master electrician and insured for the job... again a local city codes issue.
They or you will have to pull permits for the work and have the work inspected. The contractor will do the work changing everything related to the panel including upgrading the meter if necessary, up to the utility attachment point but not running wire from the utility pole. The contractor should organise with the utility co to have the run to the house upgraded if necessary.
I just upgraded my panel to a 300, involving a new panel and meter but no new wiring from the utility required. The total cost was a little over $900 in FL. I also ended up correcting a lot of issues post contractor (no 'earths' connected, no leg load balance, dedicated earth for computer stuff, shop subpanel) and had it re inspected by city without issue.
As you say unlike home with 220 lve, neutral and true earth, here the panel usually has two 110 legs and a common neutral bus. I was suprised to see that the panel case was earthed to a ground rod and house plumbing but the house circuit earths actually went to the common neutral bus and so back to the utility.
The legs are generally alternating down the panel so if you have a 110 circuit the breaker is one slot wide and attaches to one leg. For 220 the breaker is two slots wide and attaches to both legs, with the socket having either three or four conductors depending where you are and age of the house, two 110 legs and neutral / earth or separate neutral and earth. Confusingly the code in FL required a four conductor setup for my 220 shop subpanel and actually produced a setup where the neutral and earth on the four wire both being terminated on the same neutral bus on the main panel......
hope thats of use
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Not any more. Florida adopted a statewide code (the NEC) a year ago. There are no "local codes"

That is in the National Electric Code. You are isolating the current in the neutral from the Grounding conductor (AKA"earth")
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I'm not sure what you got from all these answers. Your feed is 120/240, as tou suspect. All you need is a double breaker and three or four wire cable. Four wire gives you slightly more safety and is in most codes now. 120 outlets in basements need ground fault protection. You can do it with a breaker (expensive), or with GCFI outlets. One GCFI outlet can feed others downstream.
Myself, I don't use four wire or GCFI on my 240 outlet.
Look at your box. You should find some double breakers for stove, water heater, or air conditioner.
All you need is 12 ga wire, 20A, for any reasonable shop tool. If you only run one at a time, the 30A breaker will do it. That said, it only costs a tiny bit more to pull a 10 ga wire and put on a couple of outlets for who knows what.
Having a local electrician pull one circuit "should" cost only a couple hundred bucks, but there are plenty who will gouge you. Get some bids and ask friends for recommendations. But if you are comfortable with working in the box, then it's no big deal. Just don't use it as a learning experience. We don't like to lose members unnecessarily!
Wilson

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Yeah, and you guys put those silly fuses in all your plugs. I kept thinking I had a bad run of extension cords when I lived in Ireland, than discovered they had 5 amp fuses in the plug. I replaced them with 13 amps and did not report myself to the electrical police.
Bob

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...Ireland apparently adopted the UK standard...equivalent of a plug in the US that we would use on an oven but needed just for a table lamp. Our little plug end is HUGE in the UK.
I guess it is due to some fire that they had about a million years ago (ok...was less than that but I'll have to add that it was a blessing in disguise as it burned all the black fever carrying rats) they are obsessed with fire. They don't trust the circuit breakers, which trip with static electricity on the carpet, so they also insert an in-line fuse in the plug itself.

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: stuff for us Brits, if you don't come close to killing yourself when : you : electrocute yourself what is the point?
If you electrocute yourself then you're _dead_, dork!
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Can't get much closer than that, can you Moe? I think maybe he was being a little humorous. Strong Brits, using the he-man electricity and all vs us with our wimpy little 110. Sounded funny to me and I'm not even British.
--
Larry C in Auburn, WA

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