Originally Posted by Dave_Monica
If there was a switch that would default to the 'off' position when the 120V power source is disconnected, you'd have a set-up that would be more preventative. I believe that most of the element burnouts happen when you plug in the shore power after winter storage without realizing that you left the power 'on' to the water heater after the last trip. The element to toasted after a few minutes (don't ask to how I know).
Default to off....
Some applications (like my table saw) use a self-latching
relay to control operation. Power is lost and the relay drops
out and requires the press of a push button to re-engage
when power is restored.
Might be useful for this application. Relays are likely
cheaper than heating elements.........