220v outlet install questions.


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Old 07-08-07, 09:40 PM
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220v outlet install questions.

I want to install a 220v outlet in my garage before I finish the walls. It only needs to be about 5ft from the breaker box. I have a table saw that I would like to convert to 220v because it maxes my 110v circuit. I can't remember the amps that it will draw but here are my questions:

Does the circuit breaker have to be the same as the saw or can I put a larger breaker in?

What gauge wire will I need?

I want to get a welder someday and I'm sure that would draw more amperage than the table saw. Can I design the circuit around that and safely run the lesser amp saw?

Thanks.
 
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Old 07-08-07, 10:31 PM
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A 120V device can max out the AMPERAGE of a 120V circuit, not the VOLTAGE; if it requires 120V, use a 120V circuit; if it requires 240V, then you need a 240V circuit. (I don't think the device itself can be converted from 120V to 240V.)

You need to look at the saw’s information plate/sticker where it will tell you what voltage it runs on and the maximum amperage it draws. Once you tell us this we can give you a better idea of what to do.

It is okay to have more amps than you need, but you don't want to overdo it either.

DO NOT just install a higher amp breaker or you can start a fire.

Have you done any electrical work before?

Also, if you need a 240V receptacle for your welder and the saw only requires 120V, then no, you will not be able to plug the saw into the 240V receptacle.

Post back with the requested info and we’ll try to help.
 
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Old 07-08-07, 10:45 PM
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While I will ditto making sure it can be converted, it's fairly common for high-quality table saws to be run from either 120V or 240V.

It will probably only require a 20A 240V circuit. Welders will want between 30A and 50A of 240V usually. Since it is such a short distance, run both receptacles now, but keep them independent of one another. If you are running low on space in your panel, look at the availability of tandem breakers when you go to buy them. What type panel and breakers do you have now?

Let me know what welder you are considering. You can get lots of great advice on all brands of welding machines at www.hobartwelders.com/mboard.
 
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Old 07-08-07, 11:06 PM
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Originally Posted by MAC702 View Post
While I will ditto making sure it can be converted, it's fairly common for high-quality table saws to be run from either 120V or 240V.
Sorry, I didn't know that (thanks for the info MAC702).
 
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Old 07-09-07, 05:35 AM
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Most 240 volt receptacles are installed for a specific purpose. Rarely are they general purpose or "one size fits all".

To install one, you need the specific requirements of the device to be powered. This, and the type of device, will tell you the over current and wire size needed.

Note that it is NOT necessarily as easy as sizing a circuit for 120 volts or for general purpose items. Welders, which you specifically asked about, can have wire gages smaller than seems appropriate due to their design and usage.

If you don't know exactly what you need yet, consider installing conduit so that when you do know your needs you can simply pull the correct gage wire through the conduit and install the correct size breaker and receptacle.
 
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Old 07-09-07, 07:21 AM
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It would be best if you shopped now for welders, even if you don't intend to buy now. Find welders similar to the one you might buy in the future. Figure out their electrical requirements and install the wiring and box. There is no need to install the breaker or receptacle until you actually have the welder.

Or maybe just install some large conduit and you can pull the wires later too.

Or maybe put in a couple of access panels in your finished wall so that you can install everything later.

Or maybe just open up the drywall later when you actually have the welder.

You're most likely going to need two separate circuits, one for your saw and another for your welder.
 
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Old 07-09-07, 09:08 AM
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Thanks for answering my questions. To answer yours:

Yes, I have done a fair amount of electrical work before, just never anything with a 240v circuit. My main question was if I could do a general purpose 240v outlet. Since it's not a good idea I guess I'll just run one for the saw now and conduit for the future welder.

The saw is a high quality commercial unit so it is convertable.

Thanks again.
 
 

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