Wiring Up a Mig

lute wrote: (clip) Do I then use an industrial 20 amp receptacle? (clip) ^^^^^^^^^^^ I would, based on the fact that you will not be drawing 25 amps very often or very long. I don't remember the duty cycle of the welder at max amps, but I believe it will heat up faster than the 20 amp receptacle

That's techincally a Code violation. To be legit, you'd need to change the plug on the welder to something that'll mate with a properly rated outlet, probably a Hubbell twist lock. That'd be a pain because it would tie you to that one outlet for all your welding activities.

I run my Miller 135 on a 20 amp circuit. Haven't tripped the breaker yet even though I've operated "all knobs to the right" style more than once. So I'd suggest trying that first. It'll certainly cost less for the Code compliant parts to wire it up.

Gary

sorry to hijack this tread , but i need to ask Gary about an other "wiring a mig" question

in my garage there is only one 220V outlet which belongs to the electric dryer. it has a 50amp style 3 flat blade socket

wiring from the main panel - 30 amp braker and a 6 gauge wire going to the socket. somehow i need to split that 220V into 2 socket , one for the dryer and one for the welder which supose to draw 20 amp (220V)

what would be the easiest solution ? a sub box with 2 seperate braker and bumping up the main breaker to 50amp?

thanks

Given the intermittent use of both a welder and a dryer, I don't see a problem with simply adding another outlet.

That is, tap the 6 guage cable before it gets to your existing outlet and add a junction box there. Split the feed to your dryer outlet and to another NEMA 6-50 receptacle for the welder.

Understand that you won't want to weld when the dryer is running-- otherwise you're likely to trip the 30 amp breaker.

I'm not sure about the code-compliance of a subpanel without a neutral.

It may be okay to add a subpanel without one if you only have 220V branch circuits, but I defer to the experts on this one. Gary?

If you can pull a 6 guage neutral, a subpanel would be nice because you could add a couple 20 amp 110V receptacles to run grinders, etc. If the run from the main panel is short enough (look this up) you could also up the feeder breaker to 50A so you could dry clothes while welding.

Jeff Dantzler

checked the wire it has 2 /6 gauge wire and a 10 gauge copper ground

when you say add a junction box and split....., what did you have in mind ? it has to be some junction terminal for heavier wire. no wire nuts right?

thanks

No wire nuts? Of course wire nuts are ok. Just use the proper size for the number and size wire you are splicing. That's what wire nuts are for, splicing multiple wires. Splices are only to be done in a junction box.

What I would do would be to make a short extension cord with outlets for both style plugs using a standard j-box to mount the cord and outlets, wire nuts inside the j-box ok if you have to. Leave the existing outlet and breaker alone.

I believe you have a 30 amp dryer outlet since the breaker is 30 amp unless someone has already done some fiddling with it. If you do like Jeff says and don't weld and dry clothes at the same time, you shouldn't pop the breaker.

If the outlet is actually a 50 amp outlet (normally a dryer outlet is

30 amps) and if the wire is actually #6, then you can increase the breaker size to 50A and add another outlet for the welder.

But if the outlet is really a 30A dryer outlet, then you can't increase the breaker size. In that case, you can add another 30A outlet for the welder, but make sure both aren't in use at the same time.

The breaker can't be larger than the lowest ampacity wire or outlet in the circuit. In other words, if everything has an ampacity of 50A, you can use a 50A breaker. Otherwise you're limited to a breaker size equal to the lowest ampacity outlet in the string.

The *easiest* solution is to simply use the existing outlet by unplugging the dryer and plugging in the welder when you want to weld. That requires no rewiring.

Gary

A subpanel doesn't require a neutral if no 120 VAC circuits are fed by it. But it does require safety ground, minimum size #10.

Gary

thanks Gary,

yes the outlet is a 50 amp (printed: NEMA 10-50R 50 AMP 125-250V) yes the wire is AWG 6 with AWG 10 ground. the 30 breaker was put in place to comply with the dryer circuit

sound as if the wire AWG 6 with AWG 10 ground if a perfect candidate for a sub panel, with a 30 breaker for the dryer an other 30 or 20 amp breaker for the welder an possibly 1 circuit for a plasma cutter. or I may just run the welder and plasma cutter from an extension cord with a dual socket at the end since the 2 machine will not be used at the same time , as long as i am the only one in the garage.

this way the dryer does not have to be unplugged every time. does this sound code compliant?

thanks again

Sure, but it is overkill. You don't have to install a subpanel. Just add another 50A outlet to the existing circuit. Remember, the breaker isn't there to protect plug in equipment (they'll have their own fuses for that if the manufacturer thought it necessary). The breaker is there simply to protect the wiring and outlets.

Gary

I would use #12 wire with a 20A receptacle and a 20A breaker. From what I saw of the specs the draw is 20A for rated output of welder. They are supplying a plug with the machine that is typically rated for 15A not 20A but with the duty cycle of the welder and the nature of manual welding the plug isn't going to overheat. I am guessing the 25A breaker mentioned is to allow the breaker to operate at no more than 80% capacity. Does the NEC allow you to put a larger breaker than what is normally seen as the standard for a given wire size if the load is intermittent like a welder and the circuit is used only for that purpose? In the province of Ontario I believe this to be acceptacle and our rules usually aren't too different from those in the US. Billh