you need to re-look at your Water Heater system.
it's a Suburban and the only switch inside, is for the propane operation, which works off of 12v battery power. all that electric hookups do is recharge the battery for the propane side to work.
the electric side has to be switched on from the outside of the trailer, behind the WH hatch. there's an electric toggle switch, usually has a cotter pin thru it, that has to be turned on for it to work on electric hookups.
and if you had it switched on when you hooked up to shore power and there was no water in the water heater, then you probably burned the electric element up.
and Zoe the Wonder Dog(R.I.P.)
'07 Roo 23SS pushing an '07 Chevy Avalanche
Equalizer WDH and Prodigy BC