His camper. Don't really care. Just trying to save him some money. Had an electrician wire up for my 50 amp camper. I asked him if I could just plug it into dryer circuit and he told me no. Said it would fry everything in the camper. I'm not going to take a chance. I have too much money in this one.
Modern dryers require 2 hot(120v), a neutral, and a ground.
Dryers may have a 30 amp breaker, you will need a 50 amp for the RV.
You may need a new electrician.
Also, campgrounds may have wiring issues. Get a surge protection/electronic management system for your RV because you are taking a chance every time you plug in to a strange receptacle.