Hey all!
I have a Miller 175 MIG welder (230V, 19.5A input) that comes with a 3 conducter plug.

In my current house (trying to close on it, but currently just renting) I can't run my own circuit just for the welder, so I would like to power the welder off the clothes dryer receptacle. It has one of the newer 4-conductor plug/receptacles. I have confirmed that the breaker feeding the dryer circuit is rated at 30A, so I am thinking I should be fine to run my welder off it.

I went to the hardware store and bought a 3-wire receptacle and a 4-wire dryer cord. My plan is to wire the dryer cord into the receptacle (in a single gang box that is not mounted to anything) and use this as my "adaptor."

Two questions:

1. Can you think of any problems with this setup?
2. Do I just hook both the ground and the neutral (from the dryer cord) together on the receptacle's ground pole? (then of course hook the two "hots" to each of the other two poles)

Thanks!

 

Here you can see the dryer cord pigtail and the receptacle that I want to wire it into. My welder would then plug into the that receptacle and the pigtail would plug into my wall

Clear as mud?

 

You would connect only the red black and green. If the box is metal you need to pigtail the ground to the box.

 

Planning to put it in a plastic box...figured it would be safer that way.

So, you are saying to leave both the green and white unconnected? I was planning to hook them both the ground pole on the receptacle...

 

No the green will be hooked to the ground terminal of the receptacle. What I wrote was if the box was metal it also needed to be connected to the box but that is moot with a plastic box.

A neutral is NEVER connected to ground. It is unsafe and dangerous. Cut the neural off where it exits the sheath or cap it with a wire nut.

 

Ah Ok, I apologize for misunderstanding. basically, I should just put a wire nut on the white (neutral) and just leave it unconnected. right?

 

Right......wire nut the white wire off so it can't touch anything in the box and short out.

 

It may be counterintuitive, but it is almost always safer to enclose electrical wiring, devices, splices, etc. in metal. That's one reason you don't see plastic panel boxes and utility transformers.

If you use a metal box and use a pigtail to bond it to ground, as Ray suggested, then any loose potential has a ready-made route to ground. Without that bond and that metal box, it doesn't. Someone's body might then be the most attractive path.