My water heater runs of gas or electric. Today when I left the campground to come home I left the switch on electric just wondering if this could do any damage. My battery was still hooked up and camper was plugged into my truck. I'm hoping it only works off of the 30 amp breaker when plugged in.
Some people run their WH's on electric and propane to speed up the heating process. I personally don't see the difference because my Atwood has an 18 gallon an hour recovery rate.