splitting a 220v circuit into 110's?
#11
Was thinking about rewiring my tablesaw to run at 220v-- issue is I don't have enough room in my panel to dedicate a 220 to just the one tool. The panel is in the garage, and right now i have a 20a circuit, with the outlet for the tablesaw being the first in the line. Can i put a 220 (dual pole) breaker in, run 12/3 to the outlet, wire it for 220, and then pull two 12/2's from this to use for other 110v outlets in the garage?

Colin
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#12
Short answer is, yes. Wire it as a 240V circuit (2-pole, common-trip breaker), and use individual GFCI receptacles on the two 120V circuits.

I ran my garage shop in NJ on a single 120/240V multiwire branch circuit, just like you're proposing. You just have to manage your loads; I'd run heat on both circuits (portable heaters), then shut them off when I was going to use a heavy load.
Tom

“This place smells like that odd combination of flop sweat, hopelessness, aaaand feet"
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#13
Another option is mini-breakers. Depending on what type of panel you have, you may be able to get half width breakers which allow you to put more breakers in the same panel space, I don't think you can use them for the 240V circuits because both mini breakers in a slot are on the same leg. But, if you move other circuits to mini breakers, you might be able to free up enough space to have independent circuits. Not that there's anything wrong with Tom's advice, just offering other alternatives.
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#14
Another option is to suck it up and add a sub-panel.

Surface mount near the existing to minimize the cost of heavy wiring. Using EMT conduit wire up whatever you think you need.

This would allow your 220V saw, lots of lights and other circuits and you can even add a heavy welder if you want.
Rocket Science is more fun when you actually have rockets. 

"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government." -- Patrick Henry
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#15
Of course, he didn't ask for another option. He asked for input on the idea he has. Which will work, but will require managing loads at times.
Shame on the men who can court exemption from present trouble and expense at the price of their own posterity's liberty! - Samuel Adams
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#16
The short question is: why do you want to rewire your saw for 230 volts? You will see no power increase or less cost for your electricity. In other words, there is no benefit. The saw motor doesn't care whether it is fed 120 volts or 230 volts.
Howie.........
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#17
Interesting point (and informational as well)...While I am not google:
http://www.thewoodnerd.com/articles/motorRewire.html
Others seem to have slightly varying opinions, so utilize at your own risk...
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#18
Mandrake said:


Of course, he didn't ask for another option. He asked for input on the idea he has. Which will work, but will require managing loads at times.




Umm, no, he didn't, but there's been more than one occasion that someone here suggested an approach which I hadn't specifically asked for, but wound up liking better than my original idea. I Learned about Mini-breakers here, just as an example. You seem to be suggesting that forum responses are required to only narrowly address the specific question asked, and not discuss things more broadly. If that's the case I would politely suggest that you misunderstand what a forum is.
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#19
+1 on this idea. Even if it wasn't what you asked.

Mr_Mike said:


Another option is to suck it up and add a sub-panel.

Surface mount near the existing to minimize the cost of heavy wiring. Using EMT conduit wire up whatever you think you need.

This would allow your 220V saw, lots of lights and other circuits and you can even add a heavy welder if you want.


I long for the days when Coke was a soft drink, and Black and Decker was a quality tool.
Happiness is a snipe free planer
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#20
I should add that I've been extensively into my panel twice. The first to support a kitchen remodel, the second to support a solar panel installation.

I should have done the sub-panel the first time as I had to add some half-height breakers and basically maxed out every possibility with no room for expansion. Then, I added solar and was compelled to add the panel.

I'd have been money (and more importantly effort) ahead to have done the sub in the first place.

Since the OP has an exceptionally easy way to do a sub, I'd just add a few dollars to the budget and future proof now.

Of course, we can now finish the argument of 120V vs 240V and maybe decide to do nothing. Certainly the cheapest approach.
Rocket Science is more fun when you actually have rockets. 

"The Constitution is not an instrument for the government to restrain the people, it is an instrument for the people to restrain the government." -- Patrick Henry
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