Plug question

[stravis]

I've been wanting to learn to weld for years. I'm getting a 220v arc welder tomorrow. Now I've got to figure out how to wire my shop to run it.

My question. My folks have an RV and when I bought this property, I had a 50 amp RV plug installed outside my shop so that they could pull up and plug in. Is this a 220v plug? Will it be sufficient for my welder? Might be too good to be true, but this would save me the money having to put a new plug in and I could just make an extension cord to run into the shop.

Thanks and I apologize for the amateur question.

 

[PoorPlowboy]

RVs run on 110v. On the extension cord, be sure you make a big one. Welders draw a lot of current and the shorter the length, the safer it will be.

 

[Mark @ Everlast]

No,
Many modern RV's use 240V or 120V.
Typically a 50 amp plug would be 240.
A RV 120V will be 30 amps.

Most 240V will have 4 wires and use a NEMA 14-50 plug. Hot, Hot, ground and neutral. You can use it, but you must eliminate the neutral wire from the circuit when you plug it in. Determine your two hot wires, and ground (usually almost always green wire). Hot is black or red.

With welders, you only have two hot wires and a ground. No neutral is needed or required. The correct welder plug is a NEMA 6-50. Most 240V welders use black (hot), white (HOT, not neutral) and green (ground). Be sure if you "modify" your connection you determine which is which. Don't try to hook the white wires together on the same terminal, unless you verify that the box side of the wire is hot. Most of the time you will end up hooking black to black and white to red.

 

[stravis]

No,
Many modern RV's use 240V or 120V.
Typically a 50 amp plug would be 240.
A RV 120V will be 30 amps.

Most 240V will have 4 wires and use a NEMA 14-50 plug. Hot, Hot, ground and neutral

With welders, you only have two hot wires and a ground. No neutral is needed or required. The correct welder plug is a NEMA 6-50.

So could I simply use the same wiring, but replace the outlet with a NEMA 6-50?

Again, thanks for the help.

 

[Mark @ Everlast]

See my edit above.

You'll need to cap off the neutral wire if one exists.

 

[stravis]

Thank you very much. That will save me a lot of time, effort and money. Fantastic.

 

[stravis]

Just for clarification, I don't need to replace the outlet with a 6-50, I can simply identify and disconnect the neutral and I should be good to go, right?

Not trying to be redundant, just want to be certain.

 

[Lightnsound]

You don't need to remove or cap off anything on the receptacle. Leave the outlet as-is so the RV can still hook up. Wire the correct type plug to your welder. There will be three conductors in the cable coming out of the back of the welder, two hots and a ground. There will not be a neutral wire going to the welder, so just leave that blade on the plug alone.

 

[PoorPlowboy]

First thing you do is get a multimeter to determine which wires are which and what the actual voltage you have at the receptacle. Don't rely on internet electricians to tell you what voltage your receptacle is wired as unless you want to burn up some equipment. The reason is because a LOT of people disregard NEMA when wiring things up, and wire it with what they have on hand rather than what's recommended.

I stand corrected on the "RV plug" I guess. Every modern RV in my area is 110v with onboard 12v inverter.

I wouldn't cut the plug off the welder, either, because it has the "correct" plug already. For $20 you can do the job right by adding a j-box and receptacle piggybacked on the dedicated RV circuit.

 

[deereman75]

A 50 am plug will always be 220v. Just make an adaptor, with the NEMA 14-50 plug on one end, and the NEMA 6-50 reciptical on the other end, I did this for my welder, but used a dryer plug, and a 25 foot piece of 4 gauge cable.