Water heater 110v service wire burned

[jimex]

Has anyone had this problem: 2014 Rockwood ultra lite - Suburban Hot Water heater SW6DE. The tiny on/off switch went bad (second time). I bought a new switch and went to replace and the wire to the switch was burned badly. So bad that it separated from the switch when I pulled it out. I removed hot water heater to investigate the issue. The insulation was burned back about 6-8”. The tank is insulated with styrofoam and the wire is next to the tank under the insulation. All I can assume is that the wiring insulation failed somewhere in that burned section and shorted out against the tank. All other items in the circuit are ok. No other wiring burnt. The wiring is 14 AWG 105c which is their spec.
I intend to change out the wire with a heat resistant wire meant for hot service.
It will be an upgrade from Suburban spec. The neutral wire is in the same general location but was not affected. I could not see any evidence of a short against the tank. No scarring or arc damage anywhere. No other wiring was affected. I believe the switch was impacted by the heat from the burnt wire. The breaker likely tripped when this short occurred, but I can’t verify this because I turned the breaker off when the power switch went bad and didn’t notice if it was in the tripped mode.
Anyone ever experience this? We’ve had this camper since brand new and have had very few problems.

[5picker]

Your summation is close but not quite.
You've already experienced switch issues and that is a common, weak link on these Suburban tank type water heaters

When the switch failed again, it created resistance in the connections, which then melted the wire. I've seen it several times.

You may want to pull the element and check for scale build up. It may have a heavy coating, making the element work harder than normal.

[jimex]

Thanks! That sounds like good advice. Never thought about the element. I’ll pull it and check it. Other than mechanically, what’s the best way to clean it?

[Aussieguy]

make sure you get good quality spade connectors too


use multi meter to read the OHM's of the heating element
it should be around 10 OHMS


Go here for more info and videos on measuring ohms

https://www.google.com/search?q=elec...t=gws-wiz-serp

you can even measure the OHMS on the switch to make sure your connections and switch internals are good

[kenandterry]

Originally Posted by jimex

Thanks! That sounds like good advice. Never thought about the element. I’ll pull it and check it. Other than mechanically, what’s the best way to clean it?

If it’s been awhile since you inspected your anode and element, you may as well replace it with a new one for the price. You could keep your old one for a spare, but not worth cleaning. They’re only about $20 and available on Amazon. See attached link.

https://suburbanrvparts.com/suburban...v-with-gasket/

[SailorSam20500]

Originally Posted by jimex

Thanks! That sounds like good advice. Never thought about the element. I’ll pull it and check it. Other than mechanically, what’s the best way to clean it?

Using your winterizing routine method but with the WH valves in normal position.

1. Drain WH
2. Reinstall anode/ plug
3. Open pressure relief valve
4. Pump in a 50/50 mixture of plain white vinegar and water (with valve open, this solution will just refill the WH)
5. Put WH valves in bypass setting
6. Either: Wait overnight or turn on heater for an hour.
7. Drain WH (be careful if you heated the water)
8. Rinse WH to get rid of any loose sediment.
9. Reinstall plug/anode.
10. Close pressure relief valve.
11. Reset bypass valves,

I do this process every 2-3 years as part of my maintenance routine.

[D W]

When replacing the AC water heater switch always ensure that it's rated for at least 120 VAC and at least 16 amps. There are a lot of substandard rocker switches coming out of china. I've seen some that are only rated for 12VDC and 5 amps.