Voltage on ground, POCO stumped

[Matt Harless]

Not an electrician. I'm a GC who helps my electrician when he needs it. So far, everyone is at a loss to explain my situation.
Here it is:
My family two months ago moved into a 50ish year old home. Yesterday, while checking the water pressure at an outside spigot, my 17yo son got a mild shock. He had apparently gotten somewhat wet enough to get a good earth connection. He was about 50' from the service entrance at the time. I was away so he stuck a meter in the ground(physical earth) and checked voltage on the spigot. Got as high as 40v. Varied a lot and would seem to ramp up and down slowly sometimes and other times it would jump up or down. Holds at ~20v most of the time. (as a side note, some of my plumbing is pex, some galvanized. Water heater is in the pex portion. Galvanized portion is bonded)

Called the poco, they come out and are not able to explain it. We went from maybe a bad meter, to maybe issue with transformer, and on and on. At one point they were pointing the finger at my main breaker(it is original to the house) which makes no sense to me. They were great guys, some of them not on call and still staying late at my house on Friday. We had half the company here I think, but they just had no solution.

They took all hots loose from the house, and still had voltage on the neutral. I think it was 16v at that point. Drove some ground rods, replaced the service entrance to the weatherhead, replaced the transformer, recrimped connections on various poles leading up to the house. At this point with all of that changed and nothing connected but neutral at the pole, we can read 7-10v on the ground of the house. With line voltage connected, we are getting ~12-15v to earth via the spigot.

I was reading 13v in the shower of my house from water to drain which is concerning so i removed the bond to the galvanized. It is still getting some somewhere though because there is 2v potential still in the shower.

Does anyone have any ideas? I cannot imagine a scenario where the issue is on my side but if it is that would be great and we could just get the electrician to fix it.

Also, I have 6 kids, how concerned would you be about staying in the house.

Thanks

 

[roger]

We are allowing this thread since it's only asking for advice and is not a "How To" question.

 

[herding_cats]

You have a ground/neutral bonding issue.

This can be dangerous. Seek out a qualified electrician to look at this. From what you described; the ground is being used as a neutral conductor in the home. There needs to be testing performed to see where the grounding loss is, or where the neutral is bonded to the ground. Either way.

 

[Eddie702]

I have run into something similar once. I don't know if your water entrance is a metal pipe or plastic. Your looking for a bad neutral. This could be from the main panel all the way back to the power company transformer.

But hears the kicker. It may not be your problem or even in your house. If you have a metal water pipe and your neighbor does as well it could be a loose, corroded or damaged neutral in your neighbor's service.

He loses his neutral and this puts current on his grounding system including his water service. The current travels through the earth at high resistance to you water pipe in an effort to get back to the transformer;

One way to check for this is to shut off the power to you house and put an amp probe on you GEC and see if there is current on it.

In the job I worked on I had 6 amps on the ground wire. Fixed all the neutrals and reconnected the GEC with new water pipe clamps and the poco drove additional ground rods and redid all the connections back to the transformer.

The amps dropped from 6 amps to 2 amps after all that. At that point I left and the POCO stayed working on it. Don't know what happened after that but I had proved to them the problem was not in our house.

 

[herding_cats]

I agree. It could be at the transformer/pole of the utility company. Open neutral.

 

[zbang]

IME most PoCo techs are not good at premises wiring and especially about grounding and bonding. You need someone who understands that and can take a very methodical approach to finding problems.

First question- if the problem exists when the main is off, it's probably on the PoCo side of the main. If it exists when the meter is removed, it's definitely on their side.

While your electrician tests, disconnect any cable-tv cables to the house, they too could be part of the problem.

 

[Tulsa Electrician]

.

While your electrician tests, disconnect any cable-tv cables to the house, they too could be part of the problem.

Good advise. And leads back to bonding.

 

[winnie]

There have been several threads on this sort of issue, and I agree with the points above: it us very likely that the source of this voltage is outside of your house.

First you have multiple points of earth contact which are not bonded together. Whenever current flows through the soil, you can see a voltage difference between earth contact points. Think of ground electrodes as subsurface antennas, probing the local earth voltage.

So you have a drain pipe going into the soil providing one earth electrode, and supply water pipes bonded to ground rods and electrical neutral providing the other electrode. If there is soil current then you get a voltage difference.

Same with the feet I contact with soil and the hose bib.

Dealing with this is multifaceted, trying to eliminate the source of soil currents and adding bonding to reduce the voltage associated with soil currents.

For the shower I'd get your electrician to bond the drain pipes.

Bonding the soil around the hose bib is less practical but not impossible; think about what is done for swimming pools.

Regarding the source of the soil current, possibilities include coming from the power company high voltage distribution system (imbalance can cause significant current on the shared neutral), or current limited faults on the customer side of things.

The customer side faults can be from any customer sharing a transformer connection with the OPs home. A recent thread described how a neighbor had a fault in a well which energized the well casing and injected current into the soil.

Jon

 

[Matt Harless]

Thank you for the responses. There is voltage on the neutral even when the meter is pulled, but more voltage when the meter is on. The more we draw the more there is(sort of, it doesnt seem linear or predictable really, but high loads do increase it) We have a plastic water line entering the house.

They came again today and told me the neighbors had 10v on their neutral as well. So they are sure it is on their side. After some more grounding at various poles and remaking line connections upstream from me they got mine down to ~1-2v on the ground just now. They are happy with this and I am satisfied but will keep an eye on it.

The POCO has been very responsive and are trying their best, as is my electrician, I was just asking here to cover every possibility I could.

Thank you for the suggestion to bond the drain line. Will have that done for peace of mind.

 

[kwired]

Not an electrician. I'm a GC who helps my electrician when he needs it. So far, everyone is at a loss to explain my situation.
Here it is:
My family two months ago moved into a 50ish year old home. Yesterday, while checking the water pressure at an outside spigot, my 17yo son got a mild shock. He had apparently gotten somewhat wet enough to get a good earth connection. He was about 50' from the service entrance at the time. I was away so he stuck a meter in the ground(physical earth) and checked voltage on the spigot. Got as high as 40v. Varied a lot and would seem to ramp up and down slowly sometimes and other times it would jump up or down. Holds at ~20v most of the time. (as a side note, some of my plumbing is pex, some galvanized. Water heater is in the pex portion. Galvanized portion is bonded)

Called the poco, they come out and are not able to explain it. We went from maybe a bad meter, to maybe issue with transformer, and on and on. At one point they were pointing the finger at my main breaker(it is original to the house) which makes no sense to me. They were great guys, some of them not on call and still staying late at my house on Friday. We had half the company here I think, but they just had no solution.

They took all hots loose from the house, and still had voltage on the neutral. I think it was 16v at that point. Drove some ground rods, replaced the service entrance to the weatherhead, replaced the transformer, recrimped connections on various poles leading up to the house. At this point with all of that changed and nothing connected but neutral at the pole, we can read 7-10v on the ground of the house. With line voltage connected, we are getting ~12-15v to earth via the spigot.

I was reading 13v in the shower of my house from water to drain which is concerning so i removed the bond to the galvanized. It is still getting some somewhere though because there is 2v potential still in the shower.

Does anyone have any ideas? I cannot imagine a scenario where the issue is on my side but if it is that would be great and we could just get the electrician to fix it.

Also, I have 6 kids, how concerned would you be about staying in the house.

Thanks

That tells me it comes from outside the house. POCO needs to send a competent troubleshooter out.

As someone else mentioned disconnect phone, TV, or other metallic paths just in case something coming in from one of them, but still likely coming from POCO and they have neutral issues somewhere, might be on primary side of the transformer even.

 

[don_resqcapt19]

This is very likely an issue with the utility primary neutral and that can be difficult for them to locate.

 

[hillbilly1]

I have good results locating the offending source by using an Amprobe current tracer. They are pricey if you can find one anymore, but Ideal and Greenlee makes one almost as good. It traces the current back to the source, so your electrician can find where it’s coming from, your panel, or a neighbors, or the poco. Well worth the money for your electrician if he does a lot of troubleshooting.