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-   -   adding 20amp outlet for for welder (http://www.diychatroom.com/f18/adding-20amp-outlet-welder-8169/)

Geophile 05-02-2007 03:57 PM

adding 20amp outlet for for welder
 
Hi all. I'm considering buying a small welding machine, most likely a 125v unit. All of these that I've seen advertise that they can be used with "convenient" household current, 125v, but 20 amps. However, the only 20 amp circuit I have is a 250v circuit that I installed. Due to the dual hot wire configuration of 250v circuits, I suspect that it isn't possible (at least within code), but is there any way that I could add a 125v/20amp receptacle to this loop? I would like to avoid the cost of a new, lengthy cable run for now.

My other (and perhaps likely) recourse is to replace a pre-existing 125v outlet that is very close to my panel and use the remaing 12/2 cable that I have.

Thanks for your ideas!

NateHanson 05-02-2007 04:27 PM

Do you use the 250v circuit? If not you can just swap the double pole 20A breaker for a single-pole 20A breaker, and replace the receptacle with a 120V 20A receptacle.

If it's not possible to get rid of the 250v circuit, I think you can add a 120V circuit too, if it's 12/3 romex. For dryer circuits I think you can run dual voltage outlets if there are red black and white conductors (in addition to ground).

Without the third conductor you can't do it because the only way to get 120V would be from a hot to ground, and you can't use the ground as a conductor.

Nate

J187 05-02-2007 04:30 PM

I think you can do it, if you pulled the 220 w/ a neutral when you ran it. If not, Im sure you can't. Lets see what the pros say.

jproffer 05-02-2007 04:52 PM

They're both exactly right. As long as you have 12-3 and not 12-2 feeding the 220, you can split off one hot leg and the NUETRAL (not the ground) to make a 110 circuit.

Geophile 05-02-2007 08:13 PM

I see, very interesting. Thanks for the info, everyone. So the second hot wire in 12/3 cable would enable another receptacle, or more capability in one receptacle, i.e. a 250/125v dryer-type outlet.

Unfortunately, I did only use 12/2 for the 250v, (my first wiring project, I wanted to keep it simple...) and I might as well keep it, since it isn't in a much more convenient spot than that outlet I have near the panel. (Which could be upgraded fairly cheaply even beyond the 125v level, due to its proximity.)

Incidentally, I read an anecdotal comment today that 125/20amp welders can be used on circuits with 14ga wire as long as the highest one or two settings are avoided. I'm still not certain how advisable this is, though.

So, I guess i could go ahead and reconfigure the outlet near my panel for full capacity use, while still having the potential to use the welder elsewhere, with compromise.

jproffer 05-02-2007 09:12 PM

Quote:

Incidentally, I read an anecdotal comment today that 125/20amp welders can be used on circuits with 14ga wire as long as the highest one or two settings are avoided.
I'm not as well versed on the NEC as a lot of the guys here, but I would think (maybe just common sense) that it's the maximum POSSIBLE amperage of the machine, not the maximum INTENDED amperage.

NEC or not, I wouldn't rely on me to remember 10 years from now that I'm not supposed to use the two highest settings.

Come to think of it...I wouldn't rely on ME to remember 20 MINUTES from now that I'm not supposed to use the two highest settings.:jester: :jester: :jester:

jproffer 05-02-2007 09:16 PM

Quote:

(Which could be upgraded fairly cheaply even beyond the 125v level, due to its proximity.)
OH, btw...remember you're not wanting to change the voltage, just the amperage capacity. Change the cable to 12-2 (unless it already is) and I would change the receptacle to a 20A rated rec., but that's not necessarily required.

J187 05-02-2007 10:28 PM

Quote:

Originally Posted by jproffer (Post 43220)
They're both exactly right. As long as you have 12-3 and not 12-2 feeding the 220, you can split off one hot leg and the NUETRAL (not the ground) to make a 110 circuit.

Yeah, Kinda sad that it took me more than three minutes to type that one measily line, and Nate posted in the interim, but I was multi-tasking at the time....


I agree completely that the idea of wiring something for intended usage and not what the possible usage is asking for trouble. Most of what I've seen of electricity errs on the cautious side, like the 80% rule of dimmers and such, not the other way around...

NateHanson 05-03-2007 10:32 AM

If you decide to use the welder with 14-2 cable, make sure you're also using a 15A breaker, not a 20A breaker. That way when you forget about not using the top two settings on the welder, you'll just trip a breaker instead of burning your house down.

Perhaps this is obvious, but I wasn't sure if it was what you meant.

Geophile 05-03-2007 02:12 PM

Quote:

Originally Posted by NateHanson (Post 43354)
If you decide to use the welder with 14-2 cable, make sure you're also using a 15A breaker, not a 20A breaker. That way when you forget about not using the top two settings on the welder, you'll just trip a breaker instead of burning your house down.

True enough. I was referring to two separate usage points, a rewired outlet near my panel (for which I would change wire gauge, receptacle, and breaker capacity) and standard outlets around the house, which would use 14ga cable, and I'm sure 15amp breakers as well. Thanks a lot for your concern, nonetheless. Triple/quadruple checking and lots of extra caution hurt a lot less than the alternative.

jwhite 05-03-2007 06:32 PM

It is a bad idea to plan to use this welder "on lower setting" in any rec you choose.

This line of thinking is right along the lines of "I taped the wires up and burryed them in my all and it has not burnt down yet, why are you listening to that dumb electricaian telling you that it is not ok"

If you are too cheep to wire something properly, then dont use that equipment.

Geophile 05-03-2007 08:14 PM

Quote:

Originally Posted by jwhite (Post 43436)
If you are too cheep to wire something properly, then dont use that equipment.


It's obvious how having the word "master" in one's title could make someone arrogant, but this manner of discourse isn't positive or helpful.

jwhite 05-03-2007 08:17 PM

Quote:

Originally Posted by Geophile (Post 43452)
It's obvious how having the word "master" in one's title could make someone arrogant, but this manner of discourse isn't positive or helpful.

It is also obvious that someone would want to save a few dollars on wire size. But is it worth the risk of burning down the house.

I wrote that post intending to get your attention. I am glad I did.


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