Water Heater Stopped Working on Electric / Found Burnt Wire

[LeftOverParts]

Hello MOC members. Sharing a problem with the water heater and the fix.

During a trip to Quarzsite in Jan (before the rally) we had a burning plastic smell come from the staircase. Looked in the basement, battery compartment, cord reel, and didn’t find anything. Everything seemed to work and the trip went as planned. Last week we were at Morro Bay and the hot water was on electric heat but the water didn’t get very hot and didn’t last.

Breaker did not trip. Went to see if the reset button could be pushed and the 120 VAC side was solid. Opened the cover and the first picture shows the burned-out connector, wire, and overheated thermostats. You can also see the exposed wire strands where the wire melted where it is adjacent to the metal flange of the heater shell. It appears the beaker didn’t trip because the thermostats got hot from the short and killed the power.

Second picture shows the new thermostats and wiring. Wiring is 14 AWG 600V 105C marine wire and added a fiberglass cover. Ran the wire so it wouldn’t run under the flange. That wire and cover goes to the heating element which tested OK. I checked the other wires at the top and they were dented but not worn so added a layer of electrical tape on the wires where they are adjacent to the upper flange (it’s hard to see in the 2nd picture).

Happy to report it’s working again.

Note: The plastic cover has an inner frame that looks like it would keep the wires from contacting that metal flange so sure how that wire came to short out. I thought about folding the flange over but was concerned that the gasketed surface would become too wavy. Too much work to take the outer frame and that shell off the trailer to pound the flanges flat. I’m going to check the new wire every few trips to see how it’s holding up.