30 volts on Metal water piping system.

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AC\DC

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Florence,Oregon,Lane
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EC
Hello, Got a service call, and was told the ternate got a shock while touching the hot water, and the metal enclosure for the dryer receptacle. 10 days prior some one got shocked putting in a new metal kitchen sink. So I saw I was getting 30volts from a Metal enclosure to the hot water pipe. Found it was the Hot water tank causing the issue. Then decided to look how the building bonding of the water pipe was done. There was none

I bounded The piping system under the house.​

So i have this, The Main metal underground water pipe is Split to feed the house. Then branches off and goes under ground(more then 10 feet) to feed a garage

The hot water outlet then comes in and feeds a PVC T pipe and runs next to the Cold water to feed the garage. By the looks of it, the cold water use to be an outside facet. Then they built a garage over, and added the hot water line in PVC.

So The garage is were I have an issue. The hot water is stubbed up with metal piping next to the cold. The cold is bonded but the hot is not.

So I am wondering does that stub 250.104 (A)(1) constitute a Metal Water Piping System. Do I have to run and bonding jumper all the way to that 28" stub..
I don't think it part of they system any more since it has 20 feet of PVC between metal parts.

There is no panel or disconnect in the garage, just 3-4 circuits ran in pipe over to it
 
I would not consider the 28” stub a piping system and would not bond it. At the most we would put a bonding jumper from hot to cold pipes at the water heater.

My questions:
Are there rods installed to supplement the WP? IDK if they were required at the time of construction for the house.
Was there an EG to the WH?
Did the voltage go away when power was cycled off to the WH?
Did you happen to take an amp reading on the GEC to the the CW pipe after you installed it?
Is this a community shared metal water pipe?
 
Did you check the elements in the water heater? This smells of a failed element leaking current combined with lack of bonding.

-Jon
 
Sort of sounds like a neutral issue either in the garage feeder or the POCO main.
 
We, and he, needs to know the reference point for his measurements. If neither the tank and water lines are bonded, a voltage reading between them may not mean much. It is meter dependent. My 87 would have read a considerably higher voltage than my T+Pro.

His neighbor Sharing that common water line could be the one with the possible neutral problem.
 
ptonsparky said:
We, and he, needs to know the reference point for his measurements. If neither the tank and water lines are bonded, a voltage reading between them may not mean much. It is meter dependent. My 87 would have read a considerably higher voltage than my T+Pro.

His neighbor Sharing that common water line could be the one with the possible neutral problem.
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I agree. If water pipes are bonded you still can get shocked by by contacting something that is at earth potential as the entire grounding system could be elevated due to voltage drop in the grounded service conductor.
 
All problems went away when I shut off power to the hot water heater. Hot water heater did have an equipment ground to case . I took measurements from were the clients was getting shocked in the garage from the 24” stub to all grounded points I could find. I am thinking , when the water heater was off and all voltage issue stoped it was a bad element. Am I wrong in that thinking?

one single rod was used originally as the GES
I bonded all water pipes to that after I disconnect the water heater.
 
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AC\DC said:
All problems went away when I shut off power to the hot water heater. Hot water heater did have an equipment ground to case . I took measurements from were the clients was getting shocked in the garage from the 24” stub to all grounded points I could find. I assumed, when the water heater was off and all voltage issue stoped it was a bad element.

one single rod was used originally as the GES
I bonded all water pipes to that after I disconnect the water heater.
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one rod or 100 rods probably wouldn't have mattered. all they do is create a reference to earth, but if there is current flowing they still have resistance and will have a voltage gradient around them.

Meg WH element and confirm it is the problem. Might even be bottom element has failed, doesn't heat anymore and top element has been maintaining temp near top of tank only, lessening overall capacity of the WH
 
AC\DC said:
Have not bought a Insulator tester yet. guess I’ll go get one today.
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Simple continuity test across element will likely tell you. 4500 watt @ 240 element should be ~12.8 ohms. Significantly lower than that probably is blowing breakers, significantly higher is open circuit element -and along with it probably a damaged element sheath and there is where it will leak current to the water/tank.
 
ptonsparky said:
I would not consider the 28” stub a piping system and would not bond it. At the most we would put a bonding jumper from hot to cold pipes at the water heater.

I installed a bonding number under the house next to the crawl and GES
So no bonding on the 24 inch stub!

thank you guys for your help.I fish around a lot of forums but this one is my favorite.
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