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Posted By: Electric Eagle Update on the "HOT" water & question - 07/15/03 12:27 AM
I went to the house where someone was being shocked by the water spigot and did some testing. Here's what I found, tell me what you think.

I tested the water spigot by putting one tester probe in the wet ground and touched the other probe to the spigot. It registered 13 volts AC. I also took a shoe off and touched the pipe and can confirm a nice flow of juice on the pipe. It's the same at the front and back spigot.

I checked and the pipes are bonded and from the ground in the panel a close pipe I get 0 volts and less then 1 ohm. So I know the grounding is OK from the panel to the disco where it is bonded to the neutral. From there I can see the ground wire go in the ground and I can't pull it out, but I can't see where it terminates either.

I plan to drive 2 new ground rods and see if it improves. What would you do? Any ideas.
Posted By: NJwirenut Re: Update on the "HOT" water & question - 07/15/03 01:04 AM
I would try a continuity check between the faucet giving the shocks and the main water pipe ground at the panel. Should be a LOW resistance, no more than a couple ohms. Use a length of single conductor wire to extend one of your ohmmeter leads as needed, but remember to allow for the wire resistance. Perhaps there is a piece of plastic pipe or a plastic fitting in the line somewhere between the main ground and the problem area. If so, bond around it. ALL the metal piping needs to be grounded.

If there is an electric water heater involved (storage or demand type), an insulation leakage test between the heater elements and the plumbing is a good idea. Any appliance with both an electrical and plumbing hookup is potentially suspect.

Look for cables (particularly NM) that run along/across water lines. Look for chafing, pinching or water damage.

A megger check of all branch circuit wiring to ground will reveal excessive leakage, but this is a LOT of work. You need to unplug/disconnect ANYTHING electronic from the circuits before testing the lines. This includes GFCIs.

If worse comes to worse, a separate ground wire from the hot faucet back to the main plumbing ground should stop the shocks, if you cant isolate the problem after testing.

Good Luck!
More info.

The circuit panel is in an unfinished basement. I can see all the plumbing and follow the ground wire through the house. The gruond is connected to the water line within 5 feet of entering the house. The preasure valve is bonded around. The water heater is gas and the hot and cold are bonded at the water heater. One of the water spigots is less than 5 feet from where the ground wire connects to the water pipes.

The house is less than 3 years old, but they just moved in. You did just give me an idea though. I once saw a washing machine that had a grounding problem and caused people to get shocked just by touching it. I'm going to look at that before I drive ground rods.
Posted By: nesparky Re: Update on the "HOT" water & question - 07/15/03 03:29 AM
Had a simular problem a while back. Found that some one had rep-aired a leak with PVC pipe 3' outside of the water entrance to the house. Also the neutral connection at the weatherhead was rusty.
Drove two ground rods and reterminated all the weatherhead connections. This brought a measured 40 volts on the spigots to 1.5 volts. 1 additional ground rod did nothing. Grounding the gas fired water heater did nothing.
Customer was satisfied that the shocks stopped and paid the bill. Recomended that he have the PVC replaced with copper but they have yet to do so. They do not want to see thier flower bed torn up.
Some timesx we cannot fix the real problem so we do the best we can.
Good luck
Posted By: PCBelarge Re: Update on the "HOT" water & question - 07/15/03 03:55 AM
EE

You can also try shutting the main off. Take your reading the same way as before, except don't take your shoes off, I never liked the idea of using our bodies as test equipment. If you get a reading like before, it is from the utility.
Also check the neutral connection.

Pierre
Posted By: ThinkGood Re: Update on the "HOT" water & question - 07/15/03 04:14 AM
My 2ยข:

Many faucets are connected using flexible plastic plumbing lines. Most sewers are connected via PVC pipe. Thus, I would think that gives the potential for an electrically isolated faucet; thus if the current is leaking (in the example I presented just now, with the plastic plumbing) it would be near the faucet itself or at the sink if it's metal.

Any instant-hot-water appliances, dishwasher, etc. nearby?

As crazy as this may sound, I have had excellent results in detecting current using a (non-contact) inductive probe normally used to pick up a tone placed on a wire. The AC has a nice loud hum as you get close to it. (Unless, of course, you use a filtered probe.) While I've never used it for finding something such as you described, it may (literally) point you in the right direction.

P. S. Just thought of this--would induced current, such as from a 3-conductor cable (white-black-red) be enough to give a shock?

[This message has been edited by ThinkGood (edited 07-15-2003).]
Posted By: sparky Re: Update on the "HOT" water & question - 07/15/03 11:35 AM
the bum noodle would be suspect, if in fact it is ok, take the GEC off the h2o pipe under a load, tap it on the pipe.

if it sparks, and this is a municipal h20 line all a G-rod to China won't help.....
Posted By: PCBelarge Re: Update on the "HOT" water & question - 07/15/03 12:11 PM
I know that most of the members here know this, but for those who are new to the industry, be very careful when disconnecting the grounding electrode conductor from the water pipe. If there is current there, you do not want it traveling through you.
Just a precaution!

Pierre
Posted By: Ichabod Re: Update on the "HOT" water & question - 07/15/03 02:35 PM
One possibility is a problem with telephone or cable tv. It would be easy enough to eliminate those by simply disconnecting. Another possibility is stray voltage . Have you considered the fact that the neutrals on the distribution system are bonded between substations? If you had the time you could probably trace the neutral from Alpharetta to Fairburn. That makes a mighty big system. There's no way that a system that big can have zero voltage to ground everywhere. Are the utilities underground, by any chance?
Posted By: ThinkGood Re: Update on the "HOT" water & question - 07/15/03 03:02 PM
To add to Ichabod's comment:

Telephones lines that are grounded where they shouldn't will generally have a characteristic hum on the line.

Another thought just occured--doorbell, intercom and/or thermostat transformers could also introduce AC.
Posted By: resqcapt19 Re: Update on the "HOT" water & question - 07/15/03 07:21 PM
Sparky,
Quote
if it sparks, and this is a municipal h20 line all a G-rod to China won't help.....
It will always spark in this type of isntallation because the water pipe is tied to the utility grounded conductor at the next house placing the water pipe in parallel with the grounded conductor.
Don
Posted By: PCBelarge Re: Update on the "HOT" water & question - 07/16/03 12:55 AM
Don
That is why I would like to see the cold water pipe bonded only after the water main (the water mains usually have a dielectic installed), and a Ufer ground being the grounding electrode in all new dwelling units. Then we could eliminate ground rods, which I think are mostly a waste of effort and money. I have measured many ground rod connections and the value is much higher than 25 ohms. And the neighbors problems stay the neighbors problem.
What do you think?

Pierre
Just my 2 cents. Is there an underground utility transformer on the property? That happened here in my neck of the woods. We feel that the fault lies with the POCO. Their primary cable is leaking current into the earth. The way we found it was that the EC disconnected the meter and there was still voltage on the water pipe. He also disconnected the telco and the CATV. He still had voltage. ( about 10 volts) One last thing to look for, any plastic water filters? They might need to be bonded.
Posted By: Obsaleet Re: Update on the "HOT" water & question - 07/29/03 03:13 AM
Had the same problem last week. I was able to use my greenlee tester that has a single touch prob for voltage, and then went down the panel shuting off breakers till it went away. It turned out the ridgid conduit to the garage from the 1940's and the clothe rx was getting/is the problem. I am scheduled to dig it up and install pvc etc. But for now more shocks.

Phil
Posted By: Obsaleet Re: Update on the "HOT" water & question - 07/29/03 03:20 AM
Sorry! I meant but for now no more shocks.

PS this will help you find the circuit that is in question.

Phil
It looks like the problem is POCO "leaking" current into the ground. I turned the main outside disco off and removed the cable and phone grounds from the house ground. It read 17 volts from the pipe to the ground.
Posted By: GEC-1 Re: Update on the "HOT" water & question - 08/01/03 01:27 AM
OK, let me see! You say that you read a pipe close to the panel and got 0 volts, and about 1 ohm.....right? Well you might want to look at the resistance through the pipes. Sometimes you get resistance through the pipes because of bad solder joints. Check your resistance from the spigot and at the pipe close to the panel ( where you got your readings). I believe that you will see resistance between the two points.
The guy called me today to tell me what the poco said. They told him that they were aware of the problem and not to worry about it. [Linked Image] They said because he lives at the end of a line, they have too much current flowing in the area and it's getting into the ground. They have plans to put a different transformer in to try and stop the problem.

I find it hard to believe, well not really, that the poco views this as "normal".
Posted By: ThinkGood Re: Update on the "HOT" water & question - 08/01/03 09:51 AM
Good thing the water co. doesn't have too much water in the area or you'd have that on the ground as well.

I wonder if the telco has too many lines available? Must be pretty noisy on the phone.

Is there natural gas available? Well, let's not "go there..."
Posted By: emcee Re: Update on the "HOT" water & question - 08/24/03 02:25 AM
I had a few occasions of folks being shocked from appliances and such. Every incident there was voltage from the spigot to earth. every incident turned out to be a loose neutral crimp on the service drop. FWIW
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