Every time I read about this happening, I think of the old maxim, "Trust but verify". Verifying that the new RV 30 amp outlet is correct can be as simple as opening your breaker box and making sure the new breaker is a single 30 amp similar to your other 120 volt circuits. If it's a double breaker like the one for the electric range or dryer, then DO NOT PLUG IN THE RV! The best way to verify of course, would be to use a meter at the outlet, but even the simple breaker check will save you a lot of hassles if it's wrong.
