New welder outlet wiring

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Bubba Ray

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My shop was wired years ago for 220 but no outlet was installed. I have black, red, white and green wires in box. The outlet called for by Miller is NEMA type 6-50 that has 3 connections with 1 marked ground. Do I just put a wire nut on the white wire and call it done? Thanks for any help.
 

Speedbump

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You need to know what these wires are or what they are connected to in the panel. White is usually neutral (not used in 230 volt applications) green is always ground and the other two should be the 230, but it's good to check first.

What size are these wires? A welder pulls a lot of amps and I'm thinking #8 or larger.
 

JoeD

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You won't need the white wire as you stated. But it may not be that simple.
What size are the wires? They should be #6 for a 50 amp line.
 

kok328

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It should be as JoeD noted but, as Speedbump noted, it would be wise to verify these wires instead of taking them at face value (you just never know what someone else was thinking).
 

Bubba Ray

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Wire from box to outlet is 10 gauge. I have received dif ideas on the white wire vs the ground wire to the third prong. Will not change end from welder as it is new with warranty.
 

JoeD

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The wires are too small. You can only put a 30 amp breaker on that cable.
 

Bubba Ray

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The plug is called for by Miller but the mig uses less than 30 amps.
 

nealtw

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Change the plug to a 30 amp plug.
The problem comes when the next owner says I can plug the kiln in there it's 50 amps and when that dosn't work he changes the breaker and burns down the house.
 

Bubba Ray

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No way I am going to void the 3 year warranty on a new welder by changing the plug called for by the maker.
 

alaskanengineer

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To avoid both undesirable scenarios, (and assuming the welder REALLY is 30A max (sometimes welders will have a high inrush current when using posi-start or other enhanced cold-start logic)) - what do folks think of him making an extension cord with whatever plug he needs on each end - that way he doesn't have to modify his welder and when he moves out, he takes his 30A to 50A extension cord with him and the next homeowner is left with a 30A plug and a 30A breaker - this seems to be the best of both worlds. Again, disclaimer, I ask WHY did Miller put a more expensive 50A plug on a machine if it "only draws" 30A. I suspect that will be the driving concern: as it is possible that under certain settings/conditions there is a greater inrush current....
+1 on contacting Miller about this issue - they will be able to help on multiple fronts.
 
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Bubba Ray

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alaska, good ideas. I have not heard from Miller after two emails. The power numbers come from Millers specs. Why the strange plug I have no idea but it may come from the fact that this welder can work on 120 or 220 and has a plug for each.
 
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