Originally Posted by crunchman12001
A new 50 amp plug? Did you use an adapter?
Good question, and we need to really know all the facts. Do you actually have a 30 amp (3 prong on cord) or 50 amp (4 prong on cord) RV.
I gave the advice above assuming you are connecting to a true 120/240 volt split phase 50 amp outlet. You usually only have a problem if you have an open neutral or miswiring there.
A 30 amp outlet 240 volt event is most always caused when connecting it wrong in the breaker box and wiring it for 240 volts and not 120 volts.
Check out this recent thread with post#6:
Burn out of electric converter
No white wire connected (the neutral) is an open neutral...and unfortunately, you have most likely shot 240 (or some kind of high voltage variation) volts thru the RV.