- Aug 10, 2005
Welder probably not a big deal. Fancier ones might have a 120v circuit for a control panel or something. If it is a 3 wire plug, no neutral, and is less likely to have an issue. I'm pretty sure (TS can weigh in) that any modern 240v receptacle must be 4 wire. Old school manufactures were just riding the ground as a return path if they needed 120v on their device. Not safe.
On my RV, I never, ever, plugged it in hot. Normally I would turn the main breaker off in the RV before plugging it in. Once securely plugged, I would flip the main on the RV. Inverters can be overly sensitive to voltage spikes and drops.
Have owned 3 or 4 50 amp service RV'S.....never gave it a second thought.
Current RV is wired strange though, breakers are inclusive regarding shore power or generator....so they are usually shut off while switching power supply, then flipped on after the switch..