When camping, it's on electric all the time. Of course, we do State Park camping, not metered camping too. At home, I use propane and leave it on also. But if not using it at home, I drain the tank. Fill it and fire up if using it and leave the propane on until done.
My camper is 30 amp and never had problems popping a breaker with the water heater on electric. Only once, the breaker inside the camper blew, one of the 15 amp breakers when I plugged in 2 electric griddles at the same time and my wife turned on her electric coffee pot, same circuit as the television.
Water heater is on it's own circuit. As long as we don't exceed 30 amps total, never a problem running the water heater on electric.
