Potential Fire

[concours]

Yesterday our Suburban 6 gallon hot water heater quit working. The over heat breaker nor the circuit breaker had tripped
This is what I found, the element was fine but the thermostat and the switch had melted and had been on fire the wire from the switch to the thermostat had melted and was grounded to the metal frame of the heater.
And yet the breaker had not tripped

[ChuckS]

Most likely it isn’t going to trip the 120 VAC (15) breaker inside till things got worse… IMO…

The issue appeared to have occurred “maybe” across the switch but I am guessing

The heating element is 1440 watts / 120 VAC = 12 AMPS.. the breaker downstream is rated at 15 Amps

Not sure of the year of your RV but the original PN for the Suburban switch was..
PN 233358

The new PN is now 525001

Not sure what amperage the switch is rated at but you can see by the image I’ve added it ain’t much of a switch

I also added the diagram so you could see if needed..

[concours]

The short was caused by the wire chaffing on a sharp edge of the heater frame behind the thermostat cover. My concern is that the breaker didn't trip. This was a direct short to ground.