HelloShore gfci questions here. Like many others I now have an issue when plugged into shore power gfci at home (I've used this same outlet for 5+ yrs and tried another circuit to confirm this outlet was good) I've gone through the process of elimination with the breakers. The Gen breaker is defiantly the issue. Trips the shore gfci every time. No other breaker trips it. I did accidentally turn the water heater breaker on with no water in the tank and the electric switch on. Wondering if the element is now bad and causing this even with the breaker and switch off? Is there still current trying to run through the element and shorting? Not sure if they are related in anyway. The water heater and gen share a dbl pole breaker. The fridge works fine. Everything works when plugged into non gfci. Any help would be appreciated! Thanks

Yep. That is THE classic cause of a ground fault. Turning on the electric element in the water heater without water in the tank almost instantly ruins the heating element. The heating element then makes contact with ground. That NEUTRAL/GROUND contact trips the GFCI every time. Your solution is to replace the heating element in the water heater. The breaker being on or off doesn't matter. The short is between NEUTRAL and GROUND, and neither one is disconnected by a breaker.

That was my suspicion. Is there a way to bypass the element to test? Would disconnecting the element wires do this? All my local RV parts stores are closed for another 2 weeks. I'll have to order the part.

Disconnect both wires from the element, use an Ohm meter from the element terminals to the element mount. Use a high scale. there should be no continuity. Do both terminals.Measure between the terminals. there should be continuity.Another item that trips GFCIs is the refer 129 volt element.

Bobbo wrote:Yep. That is THE classic cause of a ground fault. Turning on the electric element in the water heater without water in the tank almost instantly ruins the heating element. The heating element then makes contact with ground. That NEUTRAL/GROUND contact trips the GFCI every time. Your solution is to replace the heating element in the water heater. The breaker being on or off doesn't matter. The short is between NEUTRAL and GROUND, and neither one is disconnected by a breaker.Sorry, When a Water Heater Element "Blows", there is NO CONTAC to a ground source. The Blown part looks like a small weld slag on the element. What DOES cause a GFCI to trip is the IMBALANCE of current between the Neutral and HOT. So, When the Current tries to flow thru the Heat element, the blown element causes an imbalance, of current and the GFCI sees this as a Short to Ground. I have found very few 120 Water Heaters connected to a GFCI, but it makes sense to have it connected to a GFCI. Doug

cmt511 wrote:That was my suspicion. Is there a way to bypass the element to test? Would disconnecting the element wires do this? All my local RV parts stores are closed for another 2 weeks. I'll have to order the part.Yes, BUT there is an easier way.IF ATWOOD and less than 15 years old, unplug the outside circuit board. That will stop the 120 w/h relay from engaging at allIf SUBURBAN, just turn the exterior Black 120 switch OFF.

Heat element & shore gfci | Good Sam Community

Bobbo
Explorer II
Apr 30, 2020
Yep. That is THE classic cause of a ground fault. Turning on the electric element in the water heater without water in the tank almost instantly ruins the heating element. The heating element then makes contact with ground. That NEUTRAL/GROUND contact trips the GFCI every time. Your solution is to replace the heating element in the water heater. The breaker being on or off doesn't matter. The short is between NEUTRAL and GROUND, and neither one is disconnected by a breaker.
cmt511
Explorer
Apr 30, 2020
That was my suspicion. Is there a way to bypass the element to test? Would disconnecting the element wires do this? All my local RV parts stores are closed for another 2 weeks. I'll have to order the part.
enblethen
Nomad
Apr 30, 2020
Disconnect both wires from the element, use an Ohm meter from the element terminals to the element mount. Use a high scale. there should be no continuity. Do both terminals.
Measure between the terminals. there should be continuity.
Another item that trips GFCIs is the refer 129 volt element.
dougrainer
Nomad
Apr 30, 2020
Bobbo wrote:
Yep. That is THE classic cause of a ground fault. Turning on the electric element in the water heater without water in the tank almost instantly ruins the heating element. The heating element then makes contact with ground. That NEUTRAL/GROUND contact trips the GFCI every time. Your solution is to replace the heating element in the water heater. The breaker being on or off doesn't matter. The short is between NEUTRAL and GROUND, and neither one is disconnected by a breaker.

Sorry, When a Water Heater Element "Blows", there is NO CONTAC to a ground source. The Blown part looks like a small weld slag on the element. What DOES cause a GFCI to trip is the IMBALANCE of current between the Neutral and HOT. So, When the Current tries to flow thru the Heat element, the blown element causes an imbalance, of current and the GFCI sees this as a Short to Ground. I have found very few 120 Water Heaters connected to a GFCI, but it makes sense to have it connected to a GFCI. Doug
dougrainer
Nomad
Apr 30, 2020
cmt511 wrote:
That was my suspicion. Is there a way to bypass the element to test? Would disconnecting the element wires do this? All my local RV parts stores are closed for another 2 weeks. I'll have to order the part.

Yes, BUT there is an easier way.
IF ATWOOD and less than 15 years old, unplug the outside circuit board. That will stop the 120 w/h relay from engaging at all
If SUBURBAN, just turn the exterior Black 120 switch OFF.
Matt_Colie
Explorer II
Apr 30, 2020
Doug,

While your statement is not completely inaccurate, it is marginal at best. Sometimes they do blow out as you describe, but not always.

I have had to replace more than a few that did not "Blow Out", but create and internal short to ground. Therefore, complete disconnect test and the test with an ohmmeter as recommend are both valid for this case.

Matt
vermilye
Explorer
Apr 30, 2020
When the heater element fails, a leak to ground can be through the water in the heater. Neutral/Ground faults can occur in both refrigerators & water heaters, and will not go away when the breaker is opened.
cmt511
Explorer
Apr 30, 2020
enblethen wrote:
Disconnect both wires from the element, use an Ohm meter from the element terminals to the element mount. Use a high scale. there should be no continuity. Do both terminals.
Measure between the terminals. there should be continuity.
Another item that trips GFCIs is the refer 129 volt element.

Am I doing this correct? ohm Meter set to 2000, black to base was 4, white to base jumped all over then to 1. terminals together jump high.

Meter set at 2000k, black to base jumps then 0, white does nothing reads 1, terminals together -643. Mystery solved?
wildtoad
Explorer II
Apr 30, 2020
Suggest you go to Amazon.com and look for “RV water heater element” You might be able to get a new one in a day or so.
enblethen
Nomad
Apr 30, 2020
you did it correctly.
Bad element!

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