Electric only water heater

I have to ask, because you didn't say. Are you plugged into atleast a 15 amp plug? You can't run on electric if you are not plugged in. If you are plugged in, there are two reset buttons above the on switch on the tank. Try that. Of course check the circuit breakers. It should run on electric only, I always run on electric when plugged in.

+3. The dedicated circuit breaker in the panel and the switch on the water heater are in series. Both have to be on to heat water with 120Vac. The wall switch is for the propane water heat system only, that one does not have to be on to heat with 120vac, the two systems are completely independent. Of course, as mjlrpod says, you have to have 120Vac shore power connected to the trailer as well for the electric water heating element to work.

Don’t worry, your circuit breaker is going it’s job. Likely someone left the trailer on shore power with the electric water heater element turned on and no water in the tank. That is a no no. It will kill the element in short order. Either it will open circuit and quit working or distort and short to the tank, causing the breaker to trip. Once the element is replaced you should be good to go. If you plan to use electric water heat and don’t want to have to go outside to turn it on, leave the outside switch on and mark the breaker so you can identify it easily, then leave it turned off until you know you have the water heater filled and want to use it.