Ground current through water main/meter

[Proctologically Violated©®]

Awl--

How much is acceptable? An amp-probe reveals between 2 and 6 amps, depending on how balanced the load is on each leg of the main panel. I'm hearing that the neutral from the panel is connected to a *steel* cable outside, while the hots are indeed connected to copper conductors. This would explain some current going through ground.

If the water main connection is broken, no noticeable effect in the house--or so it seems.

Mebbe I'll amp-probe some of my neighbors plumbing. :)

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[Pete C.]

Bonding straps are generally required across the water meter to prevent potential for electrocution of the water guy if he removes the meter while there is an electrical fault.

As for what current is acceptable, in my book it's essentially zero, or at least very low milliamps. I'd carefully check all your neutral connections in your panel and meter socket and anywhere else accessible. Also check for current to your ground rod since you shouldn't be relying on just a water line for a ground.

Pete C.

[George]

Nothing you can measure with an ampprobe.

Actually its pretty unlikely a steel cable would have been used. Are you sure it isn't bare *aluminum*?

[Doug Miller]

None.

There's supposed to be a bonding jumper around it.

[Joseph Meehan]

You have a problem there. You should have nothing moving through there. You apparently have a problem with a open or very poor neutral, The only flow of current should be through the neutral and the two power legs, Current and any kind through the ground is a fault. That needs to be addressed like yesterday,

I can't imagine anyone using steel. Aluminum maybe, but not steel

[Jeff Wisnia]

How did you use that amp-probe? Was it a clamp-on type placed around the pipe or around the ground conductor attached to the pipe?

I think I understand your query, you are asking about copper and perhaps wondering about relative resistances of the two different metals.

Despite what others here said about there requiring NO current in the ground lead connected to the water pipe.....

If there's a significant imbalance in the loading of the 240 volt supply, there will be a hefty current in the neutral supply feed from the street and the drop that current creates in that feed will try and raise the potential of of the neutral and ground busses in your service panel higher than earth ground (likely by only a couple of volts). That potential could create a current flow in the grounding lead connected to the water pipe in your home.

The situation gets more complicated to analyze when you have neighbors connected to the same line transformer's secondary. Then, their neutral feeds and their earth grounds can get involved in the whole current sharing network.

Jeff

[Speedy Jim]

Time to call the utility.

An open or high-resistance neutral from pole to your home can cause the neutral unbalance current to flow via the copper water main piping to your neighbor's neutral and then back to the pole (as you suspected).

In all likelihood it's the utility's responsibility, not yours.

It's a serious issue because unexpected neutral currents can cause overheating of any of the parts in the "grounding" path.

Jim

[Proctologically Violated©®]

Both. I do have a bond/jump across the water meter (don't want any dead plumbers on my conscience!), and can just slip the amprobe over the copper going into the street. IOW, f'sure I'm measuring the right current, and all of it. Yes, the load balance affects it.

A cupla electricians around here say they see this all the time, and indeed a few plumbers got *really* jolted around town. And, the goddamm poles around here are older than Moses.

Yeah, I know it would be *better* to have zero current going thru the cold water supply, but if it's the nature of the beast around here, I can live with it. As I said, if I break this cold water pipe circuit, doesn't seem to have noticeable effect, so mebbe it is just a matter of resistance. Mebbe I just have a superlative cold-water connection!!

I may just check the c>

[Mr.E]

Agreed- Fault may be located at the transformer/aerial feeder neutral connections. The power people will need to evaluate this.

A very common type of aerial feeder triplex uses AL phase conductors with ACSR (aluminum conductor- steel reinforced) used for the bare (neutral).

[HeyBub]

"Proctologically Violated©®" wrote in message news:kcr1h.25$ [e-mail]...

Only until you our yours touches something they shouldn't. You've got a defective neutral. Here's what do:

1. Call your power company.
2. Act like the third monkey on Noah's gangplank.

[hallerb]

AFTER yopu d that try isolating the leak by tripping off breakers or groups of breakers to see if you can effect it

[gfretwell]

It should be less than the utility neutral but beyond that it is unpredictable without knowing what is on the utility side of the water line. If this is all metal pipe, the ground electrode system might be as good a conductor as a perfect neutral wire. Bear in mind the utility grounds their side of the XO terminal of the transformer too. This makes the piping system a parallel path and there is nothing you can do about it. Just be sure you have a good amount of current on the neutral and that the phases have equal voltage referenced to neutral.

[Jeff Wisnia]

At last, someone who understands parallel current paths and agrees with me.

It ain't necessarily so that the the OP MUST have hot to neutral leakage somewhere in his home's electrical system.

Jeff

[Jeff Wisnia]

Er, that was hot to ground leakage....

[m Ransley]

0 is normal, if its 6a 120v its only costing you at .12kwh maybe 750$ a year, GetR fixed

[John Grabowski]

Try measuring the current with your main breaker off. If you still have a current flow with no power going to your house, then the problem could be somewhere outside of your domain. I have heard stories of current flow coming from the neighbor's house going through a customer's grounding conductor and traveling back to the transformer via the overhead neutral.

If you have no current flow with the main breaker off, you need to have all of your neutral connections tightened from the pole down to your main panel. If that doesn't correct the problem, it is possible that you have some leakage to ground from somewhere in your house such as a defective appliance. Not too long ago I had a customer with a circuit breaker that would repeatedly trip a little while after it was reset. It turned out to be an old defective sump pump leaking current into the water.

[gfretwell]

There is an old addage that current takes the path of least resistance but that is bogus. Current takes ALL paths. The only variable is the amounbt of current. a 1" schedule K copper pipe has more metal in the crosssection than your neutral conductor and that neutral conductor is usually aluminum. If it is metal all the way back to the water plant that is a good a parallel conductor as the service drop. The OP is also correct that you can also see your neighbor's neutral current in there.

In the load (customer) side of the service disconnect they are careful about where neutral current flows but on the line side it goes everywhere. The utility bonds everything six ways from sunday and a metal water system ends up being part of that matrix.

[lwasserm]

If there really is that much current flowing through ground, it indicates a ground fault somewhere in the building wiring.

[Chris Lewis]

Consider this, then, while this conductor is indeed in parallel with the neutral to a certain extent, it's pretty much relying on the conductance of the dirt to move that 6A, at what's probably a pretty low neutral-ground voltage. Dirt generally isn't anywhere near as conductive as a copper wire. So a simple parallel current that high seems extremely unlikely.

Furthermore, that amount of current is bound to greatly accelerate any galvanic corrosion (eg: of the pipe).

It needs more investigation. I'd have it looked at. Experiment with flipping off the main breaker and individual ones.

[gfretwell]

That all depends on whether the water system is all metal or plastic. In older cities with all metal piping the water system becomes the city wide ground electrode. In newer areas everything is plastic so you really are using dirt for your ground.