I am sorry, but in my opinion house wiring and RV wiring are the same and I really do not understand this statement at all. Simple 1 leg of 120v 50 amp 240 supplies 50amp the hot side of 30 is 30amp. 20 amps more same voltage. Done!
I will drop the subject, but you missed the whole ? I am much aware of the hook up. I am on my 10th bus and have built 2 houses I'm not trying to be creative or use a cheater box. You can take high tension wire and a transformer and pull as may amps as the transformer, wiring gauge, breaker,ect will allow. If you wire a 240 stove or dryer in a residence a normal 10 gauge wire30 amp on each leg would do. I know RV is different.† Simple 1 leg of 120v 50 amp 240 supplies 50amp the hot side of 30 is 30amp. 20 amps more same voltage. Done!