I've got a problem with the grounding in my neighborhood, and I need some help in getting the right solution.

I noticed high EMF throughout much of my house, even with all appliances turned off. I shut off all power to the house at the main breaker, and there was no improvement in the situation. I found that even with the power shut off, a clamp-on ammeter registered 12 Amps going through my water main. I've followed this for a couple of days, and typically I'm seeing around 3 Amps, but sometimes it's higher.

I began to suspect that this is not just a problem with my house. I found the same situation in my next-door neighbor's basement. I measured 7 amps on their water main yesterday. However, other houses on the same block, on the opposite side of the neighborhood transformer and on the opposite side of the street do not seem to have this problem.

I repeated the test for the power company today, and showed the current on the water main, despite the main breaker being off. They checked for an open neutral, but said they couldn't detect one on the house, and then seemed to brush off the question of the current through the water main.

What can I do to make sure the power company performs the right diagnosis? I believe the current on the water main represents a shock hazard, in addition to causing high EMF via a net current on my water pipes?

This is likely a neutral issue on the power company's side. There is not much you can do to make sure they do anything, let alone have an influence on their tests. They play by their own rules.

Questions:
- What test did you perform to show this current?
- How did you "notice" EMFs in your home?

Quote:

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Originally Posted by stanfortyman

- What test did you perform to show this current?
- How did you "notice" EMFs in your home?

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The EMF has a pretty drastic effect on some audio equipment. It buzzes like a buzz saw, except at one very precise orientation where it nulls out. At first I thought it could be the nearby service panel, but the null orientation wasn't quite right for that, and I found I still had the problem when I shut off the breaker and powered my equipment off batteries.

With this result, I thought it was worth quantifying the results instead of guessing, so I picked up an Gauss meter. The Gauss meter showed very clearly that my original guess was wrong; and that the field was very clearly coming from a copper pipe running through my ceiling. (all tests I mention here were done with the main breaker off) Furthermore, when I traced some more, the largest field I found was around my water main.

I picked up one of those clamp-on ammeters, which of course if just a Gauss meter with a different label. At around 8", mG / 10 = Amps (I've verified this). By this point, I knew I'd be having a conversation with my neighbors and the power company. I figured it was worth it to be able to just read a result to the power company in a language they understand rather than to get bogged down in the conversion of units.

To show the current, I just clamped the ammeter around my water main.

I agree that it just should not be.

Most likely cause is a ground loop. Two grounds rather than one.

All your grounds should be to one central point.

Utility
Telco NID
Cable ground

The telco ground is usually just a place for a surge arrester. The cable ground is a real ground reference. That could be a source for the ground loop as well.

If you have any sub-panels, make sure they have isolated neutrals.

Also what is the length of copper pipe from the panel before it hits the earth?

What is the method that your service is grounded. It should be a ground rod.

In a near perfect world, the copper water pipe should be grounded within a certain number of feet after entering the building. If you have to run a #6 wire from this location to the panel, so be it.

The utility should smay ground it's service at the pole as well. This can be a cause for a loop.

If their surge suppression is bad or your telco connection is bad, you can have major ground loop problems.

Finding that elusive referenc point without the utilities help is going to be difficult.

Quote:

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Originally Posted by boltsnvolts

To show the current, I just clamped the ammeter around my water main.

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WOW. Yeah, that'd do it. :eek:

Here is a link for recommended practices for installing overhead transformers. Note the ground at the pole.

http://www.jea.com/about/pub/downloa...ansformers.pdf

You have ground rod at the service entrance as wel.

We have to think about what can cause 12A on your water pipe.

An open neutral between the pole and your house would do it.

If the pole ground is accessible, I'd bet you would find a voltage between the transformer pole ground and the ground in your house.

Thanks to everyone who responded. I explained to the power company that I was seeing a net current on my water main, and an equal net current on my service drop. It took a few days of phone calls and two visits, but everyone who understood what I was talking about took it pretty seriously.

Today I got a tech who was willing to check my neighbor's service as well as my own. He didn't see much of an issue with my own neutral (I didn't think he would), but saw just enough so he was willing to consider it further. When he got to the neighbor's house he immediately diagnosed the neutral problem, put up a temporary neutral, and said they'd be digging in a week or so to replace the old one (we have underground power here).

Another supervisor I talked to was very grateful that I had done the leg work of mapping the issue around the neighborhood and diagnosing the problem for them. He said they see this fairly often. However, until someone reports it and there's a critical mass of information, they just don't know it's there. So, I guess the lesson learned about dealing with the power company is to document as much as possible, explain it succinctly, and persist until you get someone on the phone who knows what you're talking about.

With the temporary neutral in place, I'm now reading 0.00 Amps on the water main, and 0.0-0.2 mG of EMI throughout my house.

So, you were reading the net current of Lline 1 and Line 2 on your water line and none on your own neutral before it was fixed?

I'm surprised anyone took you seriously. I'm not sure Verizon does. You can tell them that there is 5 VAC on the line at the NID at the test port and they will tell you it's in the house and won't come out.

The net current on the water line was coming from my downstream neighbors. Because their neutral was faulty, the next best return path was through my neutral, via my copper plumbing and the water main. The total amperage would have been what all of my downstream neighbors were consuming.

In my service drop, lines 1, 2 and the neutral are in one cable. There should have been 0 amps on the package; because, if only my house were being serviced, the neutral would be returning current for line 1 and 2, and the three together would have added up to zero. You can test this on your dryer plug, if you don't have a similar drop handy.

However, the net current on the water main always matched the net current on the service drop. i.e. the current above 0 on my service drop was due to exactly what I was getting from the water main.

Yeah, I was surprised I was able to get through it. I think the 1st tech didn't quite seem up on it, but he still referred the case for further analysis. One of the phone operators seemed to be reading from a script, but she still called back for more info, and passed it on. The others took very detailed notes and passed them on to the right people, gave me the names and direct numbers of specific supervisors, etc. I was impressed. They were a lot more flexible of an organization than I had expected.

Nice explanation. Thanks.

You got a greenie.