GFCI connection to water heater

[Ken.]

Have a new to me 2018 21' ET and in the course of playing with the systems I unplugged the Suburban anode and drained the tank. Before I did that the trailer was plugged in to a garage GFCI protected outlet. With he anode out and the tank empty, the GFCI switch tripped. I replaced the anode and refilled the water tank and the GFCI switch accepted the load without tripping. The water heater switch was off the entire time of this process.

So, my question is "Why?". What is the connection between the anode being in or out and the tank full or empty to the GFCI outlet since heater itself was always off? As far as I know I do not have a current problem, only a mystery.

Appreciate your thoughts.

Thanks,

Ken

[tdf-texas]

Originally Posted by Ken.

Have a new to me 2018 21' ET and in the course of playing with the systems I unplugged the Suburban anode and drained the tank. Before I did that the trailer was plugged in to a garage GFCI protected outlet. With he anode out and the tank empty, the GFCI switch tripped. I replaced the anode and refilled the water tank and the GFCI switch accepted the load without tripping. The water heater switch was off the entire time of this process.

So, my question is "Why?". What is the connection between the anode being in or out and the tank full or empty to the GFCI outlet since heater itself was always off? As far as I know I do not have a current problem, only a mystery.

Appreciate your thoughts.

Thanks,

Ken

My guess would go like this: The hot water tank has a ground connection. When you pulled the anode, there was a stream of water from the tank to earth ground that connected the trailer electrical ground to earth ground. The GFCI didn't like that connection.

You might want to measure the voltage from your trailer ground to earth ground (ground rod, water pipe, etc.). If you can measure a voltage, the GFCI will see it as well.

[C&G in FL]

The electrical connections on the water heater are in a metal “box” and the water heater is enclosed in a styrofoam jacket. I personally find it difficult to believe that water flowing out of the (anode) drain would cause any type of ground fault.

[tdf-texas]

Originally Posted by C&G in FL

The electrical connections on the water heater are in a metal “box” and the water heater is enclosed in a styrofoam jacket. I personally find it difficult to believe that water flowing out of the (anode) drain would cause any type of ground fault.

Electrical ground is attached to metal box. Metal box is attached to hot water heater control housing. Hot water heater control housing is attached to tank. All the metal parts of the hot water heater have a path to ground per code.

[C&G in FL]

Originally Posted by tdf-texas

Electrical ground is attached to metal box. Metal box is attached to hot water heater control housing. Hot water heater control housing is attached to tank. All the metal parts of the hot water heater have a path to ground per code.

Tom, with all due respect, I understand your theory (which you have labeled a guess) and while it makes some degree of sense (and given your technical background) it could be valid, I am not convinced. When in storage, my trailer is connected to a GFCI protected outlet 24/7. I have drained the water heater numerous times and have never tripped the GFCI resulting from water streaming on the ground. And yes, my GFCI is functioning properly. I would be curious to see if the OP would get the same result if he drained the water heater again under the same circumstances.

[tdf-texas]

Originally Posted by C&G in FL

Tom, with all due respect, I understand your theory (which you have labeled a guess) and while it makes some degree of sense (and given your technical background) it could be valid, I am not convinced. When in storage, my trailer is connected to a GFCI protected outlet 24/7. I have drained the water heater numerous times and have never tripped the GFCI resulting from water streaming on the ground. And yes, my GFCI is functioning properly. I would be curious to see if the OP would get the same result if he drained the water heater again under the same circumstances.

I agree. The GFCI should not trip if the circuits are working correctly. That's why I suggested measuring the voltage from the trailer ground to earth ground to see if there is a problem with the trailer wiring.

A GFCI monitors the imbalance of current between the ungrounded (hot) and grounded (neutral) conductor of the protected circuit. If the ground has as little as 5ma of current leakage from the hot conductor to ground, it will trip the GFCI.

So back to the OP's situation. He dumped the water out of the hot water heater. That somehow caused at least 5ma current from the hot to ground tripping the GFCI. Now the trick to figure out where the current came from. First place to look - measure voltage from electrical ground to earth ground. If it's there, then we continue the search until we find out what caused the voltage to be there.

If it's not, the next place to look would be if somehow he got water in the on/off switch. That would do it as well. It should be sealed from water intrusion but the OP's may not be.

[Ken.]

Tom and Carl,

You have carried this discussion beyond my knowledge, which is why I posted the question. Thanks! This afternoon I will conduct a retest to see if the GFCI trips again and if so I will dig out my multimeter to test the voltage on the ground wiring. What I can say is this: It was several days after I initially drained the water heater that I noticed the GFCI had been tripped. I think I would have noticed right away but maybe not. I'll watch closely this time.

I don't see how I could have gotten the on/off switch wet; it's high on the wall inside the trailer near the refrigerator. The refrigerator has never been used by us in the month we have owned the trailer.

Testing continues and I will let you know what happens.

Thanks,

Ken

[steve dunham]

Originally Posted by tdf-texas

My guess would go like this: The hot water tank has a ground connection. When you pulled the anode, there was a stream of water from the tank to earth ground that connected the trailer electrical ground to earth ground. The GFCI didn't like that connection.

You might want to measure the voltage from your trailer ground to earth ground (ground rod, water pipe, etc.). If you can measure a voltage, the GFCI will see it as well.

Tom , If the equipment grounding conductor to the trailer is defective then the trailer’s frame and equipment would be floating If there is a small amount of leakage current to the equipment ground or trailer frame there would be no place for that leakage current to flow , (Floating) it would only be potential . When you remove the anode , water would flow from the grounded water heater tank to the earth providing a path for the leakage current thus tripping the GFCI
When the water guits flowing the ground path is removed and the GFCI would hold
Am I on the same path as you? or off on some wild tangent

[tdf-texas]

Originally Posted by steve dunham

Tom , If the equipment grounding conductor to the trailer is defective then the trailer’s frame and equipment would be floating If there is a small amount of leakage current to the equipment ground or trailer frame there would be no place for that leakage current to flow , (Floating) it would only be potential . When you remove the anode , water would flow from the grounded water heater tank to the earth providing a path for the leakage current thus tripping the GFCI
When the water guits flowing the ground path is removed and the GFCI would hold
Am I on the same path as you? or often on some wild tangent

Yep. My thought was that checking the potential to ground from the hot water heater would be the quickest way to find out if a ground was loose somewhere. It could be loose in the junction box on the side of the heater, at the ground connection at the breaker box, etc. So a quick check and go from there.

[tdf-texas]

Originally Posted by Ken.

I don't see how I could have gotten the on/off switch wet; it's high on the wall inside the trailer near the refrigerator. The refrigerator has never been used by us in the month we have owned the trailer.

Testing continues and I will let you know what happens.

Thanks,

Ken

If you look at the left hand side of the hot water heater enclosure, you will see an on/off switch. That's the switch you would use to turn on or off the electrical hot water heater element. If that one gets wet, it could cause a GFCI to trip.

The one above the fridge is for the propane on /off.

If you drain the hot water heater, you should turn off that electrical on /off switch or your hot water heating element will fry if power is applied. Hopefully, you turned it off when you drained your heater or it might be gone already and the heater element burning up could have been why your GFCI tripped.

[C&G in FL]

Originally Posted by Ken.

Tom and Carl,

You have carried this discussion beyond my knowledge, which is why I posted the question. Thanks! This afternoon I will conduct a retest to see if the GFCI trips again and if so I will dig out my multimeter to test the voltage on the ground wiring. What I can say is this: It was several days after I initially drained the water heater that I noticed the GFCI had been tripped. I think I would have noticed right away but maybe not. I'll watch closely this time.

I don't see how I could have gotten the on/off switch wet; it's high on the wall inside the trailer near the refrigerator. The refrigerator has never been used by us in the month we have owned the trailer.

Testing continues and I will let you know what happens.

Thanks,

Ken

Ken,

This brings up another question. Is your water heater dual fueled (two way). Some are only heated with propane. The switch you describe is the auto igniter for propane. If your water heater also has an electric element, then there will be a separate circuit with circuit breaker labeled “water heater” and a switch on the water heater itself. It will be on the lower left of the heater itself, accessible through the outside hatch you open to drain the water out. Please check and let us know. Fortunately, Steve Dunham has gotten involved in your question and as a retired electrician, is quite knowledgeable in all things electrical.

Edit: Sorry, Tom. I see you addressed that while I was writing a response.

[steve dunham]

Originally Posted by C&G in FL

Ken,

This brings up another question. Is your water heater dual fueled (two way). Some are only heated with propane. The switch you describe is the auto igniter for propane. If your water heater also has an electric element, then there will be a separate circuit with circuit breaker labeled “water heater” and a switch on the water heater itself. It will be on the lower left of the heater itself, accessible through the outside hatch you open to drain the water out. Please check and let us know. Fortunately, Steve Dunham has gotten involved in your question and as a retired electrician, is quite knowledgeable in all things electrical.

Edit: Sorry, Tom. I see you addressed that while I was writing a response.

I know just enough to be a PITA as others can testify

[tdf-texas]

Originally Posted by C&G in FL

Ken,

This brings up another question. Is your water heater dual fueled (two way). Some are only heated with propane. The switch you describe is the auto igniter for propane. If your water heater also has an electric element, then there will be a separate circuit with circuit breaker labeled “water heater” and a switch on the water heater itself. It will be on the lower left of the heater itself, accessible through the outside hatch you open to drain the water out. Please check and let us know. Fortunately, Steve Dunham has gotten involved in your question and as a retired electrician, is quite knowledgeable in all things electrical.

Edit: Sorry, Tom. I see you addressed that while I was writing a response.

If Ken's hot water heater is propane only, pretty much all of this conversation would be irrelevant as the hot water heater would have no power other than the igniter circuit.

[C&G in FL]

Originally Posted by steve dunham

I know just enough to be a PITA as others can testify

Perhaps, but I would defer all electrical questions to you. Besides, both Floyd and Tom K tell me deep down you are an OK guy!

[rubicon327]

Originally Posted by tdf-texas

If you drain the hot water heater, you should turn off that electrical on /off switch or your hot water heating element will fry if power is applied. Hopefully, you turned it off when you drained your heater or it might be gone already and the heater element burning up could have been why your GFCI tripped.

Yes, check the electric element if you have one. The element can fail hot to ground. This is what happened to us:
http://www.escapeforum.org/forums/f3...tml#post145401