Making 220 from two 110's in garage?

zaappedDecember 15, 2009

I have a welder that I run on 220 with a 50amp breaker. I recently moved and my garage is in the rear of the home. The breaker panel is in the front of the home and its hard to run wire to the garage for 220.

I was told that I could connect two seperate 110 outlets both running on seperate breakers in such a way to create a 220 circuit in my garage. Can this me done and if so, How?...Thanks, Douglas

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Because of the high current demand of the welder, 50A, you can't use typical 14 or 12 gauge wire from existing 120V circuits in the garage to make a new 240V circuit. You will have to run new cable from the panel.

    Bookmark   December 15, 2009 at 11:43AM
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Ron Natalie

In addition, you can not just grab two 110 branch circuits (regardless of whether they are connected to the opposite legs) and turn them into a 220 circuit.

Whoever "told" you this is a dangerous idiot.

    Bookmark   December 15, 2009 at 12:06PM
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This would be easy to do if you didn't need 50A. You would need a dedicated, not shared, 120V circuit. You would remove the white (neutral) wire from the neutral/ground bus. Then mark this white wire with a black piece of tape and connect it to an empty breaker adjacent to but on an opposite electrical leg from the breaker that its black wire is currently connected to. Code now requires that both breakers be joined with a tie bar, or just use a new 2 pole breaker. The most important thing is that no other 120V receptacles or devices can now be used on that circuit, only 240V devices. If there were other devices on that 120V circuit, they would have to be removed or disconnected, and any device boxes would then have to become covered junction boxes.

    Bookmark   December 15, 2009 at 12:49PM
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Thanks bigbird. What do I need to do if I want to come out of the breaker panel from a 50amp breaker and run some burial wire around the house to the side of the garage and then put in a 220 recepticle. Can I come out of the front of the panel? what size wire would I need to go 60 feet. I'm not sure that I can go through the attic and to the garage from the panel

    Bookmark   December 15, 2009 at 3:17PM
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You can have your cable leave the main panel through any knockout in the sides, top, or bottom of the panel. If you were adept and had a punch set, you could even make your own knockout. You can't exit from the front of the panel, as you would then have no way to remove the panel cover. For 60' of 50A cable, you would need #6 copper cable. If it's 240V only, you would need 6/2 with ground.

    Bookmark   December 15, 2009 at 3:46PM
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" garage is in the rear of the home."

If the garage is attached to the house you just need a new 240 V, 50 A branch circuit.

If the garage is detached, you need a sub panel since you can only have one circuit to a detached building without a sub-panel.

    Bookmark   December 15, 2009 at 4:49PM
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Sounds like the OP has an attached garage at the rear of his home.

    Bookmark   December 15, 2009 at 6:24PM
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Ron Natalie

I agree with BB, since he already has apparently multiple circuits out there.

    Bookmark   December 16, 2009 at 7:49AM
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"I agree with BB, since he already has apparently multiple circuits out there."

A MWBC could be in use, but I would never take the presence of more than one circuit to indicate attached.

There are plenty of uninspected installations in violation already.

    Bookmark   December 16, 2009 at 8:52AM
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Thanks for the reply's to all...Yes my garage is attached and part of the home. It's just one of those that is in the rear with a driveway that runs down the side of the home. The breaker panel was installed in the front/side of the home opposite of the garage.

    Bookmark   December 16, 2009 at 11:56PM
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I have a detached garage. The main (only) breaker panel is in the garage. Is my house a detached building? do I need a subpanel in my house?

    Bookmark   December 20, 2009 at 9:07PM
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Umm... (re-reads a few more times) yes.

Are you saying your breaker box is in... the garage... which is NOT attached to your house... but your house still has multiple circuits, attached to multiple breakers... in the garage... ?

That's... weird, at best, and I'm pretty sure it's not legal.

Yes, I HAVE seen a main panel in a garage feeding a subpanel in the house. Not quite "common" but not unusual up here. Quite often the "house" is a mobile home that became permanent.

    Bookmark   December 21, 2009 at 12:56AM
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I am more of a welding expert than an electrician. I bought an old steampunk 220v arcwelder (Lincoln IdealArc 250 its like 60 years old and the manual says it is 50 amp). Truth be told it is really more like 43 amp max and I simply plugged it into my 30 amp dryer outlet and haven't popped the circuit breaker once with it ever. So yeah get an electrician to throw you a basic 30 or 40 amp 220 outlet and you ought to be fine.

I could be wrong but I think the main issue with using 110 lines is the wire gauge with 20 and 15 amp lines using like 14 or 16 instead of the 12 or 10 gauge needed for 30 or 40 amp the 50 amp requires (I think) 8 gauge super heavy wire. So the issue isn't if you can do it but if those light weight wires could carry that much current amps without melting and causing problems. Just remember volts X watts = amps so using two lines does in fact double your current carrying capacity but you are still pulling the same required 30 amps across two household wires rated for typically 15 amps (20 amps if the left plug looks like a sideways letter T).

If you were to try anything like that you should be sure to use GFCI outlets so that they pop early instead of cooking the lines. I actually have an electric oven in my kitchen that does this - pulls two 110v lines to generate 220v and it does it just fine for 16 years now.

Again the wire gauge versus amps rating chart I believe looks like this:

gauge amps
8 50
10 40
12 30
14 20
16 15 (typical household outlet)

the reason to match wires to current amp rating is because they use cheap stuff like aluminum and all sorts of junk in those 15 amp household wires and extension cords so you can melt them pretty quickly pulling 40 amp arcwelder type currents through them

    Bookmark   December 12, 2012 at 5:53PM
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and the above post is EXACTLY why people that don't have a clue at all about electrical should NOT POST.

why aren't there moderators on here that can actually do something and delete posts like this before someone gets hurt?

    Bookmark   December 12, 2012 at 6:14PM
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Ron Natalie

"Informative" dredges up a three year old post, to put a post that is at best complete drivel and at the worst dangerously misinformative.

    Bookmark   December 12, 2012 at 7:26PM
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This is a very good example of when having some mods would be helpful. I do searches for information and too often do I find a post that someone dug up and added to with jibberish and no one caught it and if I didn't research further I could have ended up in a pickle.

Luckily in the hvac and electrical forums most of this is caught and brought back in line rather than ignored.


    Bookmark   December 13, 2012 at 12:51AM
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I couldn't agree more with the last three posts.

    Bookmark   December 13, 2012 at 9:02PM
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Well, I thought it has some entertainment value...;-)

    Bookmark   December 14, 2012 at 12:39PM
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