As long as the welder is rated at less than 50 amps.

Maybe I'm off here but aren't RV hook-ups 120/240v four wire (hot, hot, neutral, ground) while most welders are straight 240v with three wires (hot, hot, ground)? I suppose you could use a 4 prong plug on the welder if you made darned sure you got the wires in the right place although I'm not sure that meets code.

" I suppose you could use a 4 prong plug on the welder if you made darned sure you got the wires in the right place although I'm not sure that meets code."

It will work fine with only the required conductors hooked up, and it not a code violation.

You are not restricted to only using 3-wire loads in a 3-hole receptacle any more than only using 4-wire loads in a 4-wire receptacle.

Plugging in a 2-wire lamp is just fine.

Yes, My welder is three wires (hot, hot, ground) My hope was that I could just plug the three wire plug into the four wire outlet picking up the hot, hot, ground, and ignor the neutral. Sound like that will work which will save me from adding a seperate welder connection. Thanks for your help.

"My hope was that I could just plug the three wire plug into the four wire outlet picking up the hot, hot, ground, and ignor the neutral. Sound like that will work which will save me from adding a seperate welder connection. "

Unlikely without changing the plug on the welder.

Receptacles are designed to prevent wrong type of plug from being inserted.

Unlikely without changing the plug on the welder.

Bummer

I have a device for just that purpose, it consists of a NEMA 14-50P plug, NEMA 6-50R receptacle and a short length of 6-3 SOOW cord. It took about 20 minutes to fabricate.

i saw at a local mechanics shop them connecting a 6-20r to a 6-50r using a replacement plug, a 4x4 box and some emt. no qo cb box or any cb or fuse for that matter.

Changing a plug is pretty simple.

Larger welders do not even come with a cord or plug, just a terminal strip.

I have a device for just that purpose, it consists of a NEMA 14-50P plug, NEMA 6-50R receptacle and a short length of 6-3 SOOW cord. It took about 20 minutes to fabricate.

Of course. Thanks