PastorCharlie wrote:
Same wires just change out to RV receptible. Make sure of correct wiring connection.
Not quite "the same".
240V stick welders do not have a neutral wire and that is a big deal concerning a RV.
50A stick welders only need the two "hots" and a safety ground and more often than not when that outlet was installed no neutral wire was run, there was no need for it and therefor no need to spend more than needed. Typically welder outlets have been wired using 6ga-2 with 8ga ground..
Looks like this..
The white wire will be repurposed for a Hot by taping up the exposed white insulation with black tape (one of a couple exceptions that are typically allowed)..
Right about now you are thinking why not just use the ground wire as the neutral, it terminates at the same spot as a neutral in the main breaker panel? Right?
Technically you are correct, however, electrically it is a bad idea as the ground wire that is run typically will be one or several wire ga size smaller and will not handle the full 50A without overheating.
Additionally, you would now have a voltage and current running on a wire that may not have electrical insulation if Romex was used creating a potential hazard..
If OP does not have a "spare" unused wire (white) in the outlet box, then they will need to replace the existing Romex wire with proper Romex that includes a white wire for neutral plus ground.
In the case of 50A RV setup, you would need 6 ga-3 with 8 ga ground.
Looks like this..
Now you have the obvious question, why can't I just run a separate neutral (white)?
Technically you would be correct but last time I checked it was not allowed by electrical codes, kind of doubt that it has been made an exception..
If OPs wire is conduit and the conduit is sized large enough then they might be able to run a neutral.. If conduit is not large enough then they would need to replace conduit or run new Romex..