Water Heater Switches Creating a Direct Short and Blowing 15 Amp Fuse

[4riveteers]

Here's the scenario-2016 27' FC TB with 50 amp service and a Progressive Dynamics PD4600 purchased new July 2016. Have taken AS on less than 20 outings with partial hookups at the least. Always use a surge protector at pedestal.

15 Amp fuse started blowing out when we flip the electric or gas heater switches on two trips ago on 10/6/17.

Two trips ago, we had full hook ups. Did a process of elimination while on shore power and isolated the water heater switches as the culprit. Disconnected water heater. No more fuse blowing. Discovered refrigerator, water pump, Garnet, range hood exhaust and water heater switches are ALL on the same circuit. So to say the least my wife took cold showers.

Returned home. Connected to my 50 amp service with surge protector and turned everything on to re-create amp usage. Everything worked fine. No blown fuse. Thought everything was fine...

This weekend's outing we're experiencing the same blown fuse crisis. Isolated the same problem again with the water heater switches while on shore power. However this time I also disconnected from shore power: Propane water heater switch did not create a short but water heater did not turn on at all. Turned on electric switch and the fuse blew.

Anyone have any advice? Thanks ahead for any help.

P.S. We live in California. Unfortunately we deal with the epitome of "California has the worst highways". We're thinking maybe something got jarred?

[TRIPPPIN]

Does the same thing happen if you only heat the water with propane? In my trailer when it is on electric I cannot run some other items on the same circuit or the fuse will blow. Some water heaters I have seen have 1650W elements which is about the max for a 15A circuit.

[A W Warn]

Clarify: fuse (12v DC) or breaker (120v AC), which is the problem? Some water heaters have both.

First thing I would do (with shore power disconnected) is look at the back of the switch for a loose wire that moves/shorts as the trailer is towed. Second, follow the wires toward the water heater looking for skinned places in the wire's insulation. Third, where the trailers wiring connects to the water heater's wiring look for missing wire nut or other connector.

Good luck!

[Mike S.]

The problem of popping fuses and breakers obviously needs to be addressed. I would think the water heater should've worked on propane though. Was it trying to light? Maybe the propane just hadn't had a chance to get there yet. Mine takes a few times before it lights. And on my trailer, the switches were connected backwards. Easy to fix. Just a thought, Mike

[Airjeep]

Here is a issue that I found with our water. Noticed a hot, plastic smell when in the bathroom with the water heater on shore power. Turn off the breaker, checked for smell after an hour or so, no smell. Turned power back on and after several minutes, smell returned. Turned off breaker and open the junction box on the heater. Found that the wire connectors were partially melted, one of the wires with 105ºc insulation mostly melted off and a small hole in the end of the heater element.

Think the cause was the romex only had a short amount -2"of the outer jacket removed thus keeping the wire connectors in contact with each other. This would cause the heat to be focused at the joints causing over heating of the wires instead of dispersing.

Could have shorted out or maybe caused a fire. It is easy to check and urge all to check to be sure you won't have this issue

[Airjeep]

Here are some pictures

[JCWDCW]

I'm thinking maybe a fault in the electric element. Disconnect the hot water to the element and see if it does it. If not you have two choices. The element is faulty..but if it was shorting to ground the GFI should have tripped. Or the wires at the switch or somewhere else may have been poorly connected. After a lot of use the poor connections finally corrode and cause a hot spot. Only place to look for connections would be at the switch and at the HW heater since there is no reason for any other connections on the straight run of 120V power.
If you have the ability try to check the current flow...it should tell you something compared to electric element specs
JCW

[gklott]

Wow! So glad you found the likely source, burned wiring.

1. As described by UL, you likely experienced a "glowing connection". This is a common cause of house fires. Suspect wire nuts vibrating loose or being improperly installed, causing high resistance, glowing point. This is all too common in poorly wired RVs.

Still under warranty? If so, have dealer repair by replacement.

2. Insist that the repair person is a licensed electrician or RVIA "certified technician". Have them show you the certificates.
3. Write on the repair order that the technician use UL-listed crimp type connectors. Twist on wire nuts should NEVER be used on an RV.
4. If possible, install 15A AFCI/GFCI combo OCPD (i.e., circuit breaker) for the water heater. On our trailer's water heater, the breaker must be 15A because the wiring inside the heater junction box is 14 AWG.

UL stated the value of combining GF with AFCI protection. "By virtue of this worse case configuration*, it was demonstrated that a Branch/feeder AFCI incorporating equipment ground fault protection (30 mA trip) is capable of terminating a glowing connection by sensing the differential current associated with thermal degradation of the wiring device insulating material(s).”

This is one reason why our new 50A panel uses AFCI/GFCI combo breakers on ALL branch circuits.

RV electrical wiring environments are similar to the marine industry. The Marine industry has learned:
ABYC E-11 11.14.3.6 "Twist on connectors, i.e., wire nuts, shall not be used."

73/gus

[Airjeep]

Originally Posted by gklott

Wow! So glad you found the likely source, burned use UL-listed crimp type connectors. Twist on wire nuts should NEVER be used on an RV.

73/gus

My understanding is that crimp connectors are not suitable for solid wire. If so what is the recommended way to join solid and stranded wires? Split bolt?

Cheers, John

[gklott]

Originally Posted by Airjeep

My understanding is that crimp connectors are not suitable for solid wire. If so what is the recommended way to join solid and stranded wires? Split bolt?

Ideal 2006S Crimp Connector
Ideal 2007 Splice Cap Insulator
Ideal C24 Crimp Tool

2006S instruction sheet says:
"UL and CSA listed as “pressure type wire connectors” and “fixture-type splicing connectors” for 2-10 #18, 2-7 #16, 2-5 #14, 2-4 #12, 2 #10 stranded and/or solid wire. UL listed for grounding equipment. Consult factory for complete listing. Copper wire only."
https://www.idealind.com/content/pdf...structions.pdf

I purchased and always use the C24 crimp tool. However, the instruction sheet lists "Alternate UL Listed Tools".

73/gus

[Al and Missy]

The newer water heaters use 12V exclusively to control the heater. Turning on the propane switch sends 12V down one line to activate the propane heating. Turning on the AC switch sends 12V down another line to a relay which turns on the 120V heater element.

I'd suggest putting the trailer in store mode, disconnecting from shore power, and pulling the water heater switch panel to look for a loose or broken connections.

Open up the access panel to the water heater and inspect the wiring there for loose or broken connections.

Al

[4riveteers]

Thanks all for all your advice. It came down to a faulty circuit board. Replaced it and everything works like a charm!

Happy travels! John