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#27412 - 07/14/03 08:27 PM Update on the "HOT" water & question  
Electric Eagle  Offline
Member
Joined: Apr 2002
Posts: 914
Alpharetta, GA
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.


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#27413 - 07/14/03 09:04 PM Re: Update on the "HOT" water & question  
NJwirenut  Offline
Member
Joined: Sep 2001
Posts: 806
Bergen County, NJ
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!


#27414 - 07/14/03 10:08 PM Re: Update on the "HOT" water & question  
Electric Eagle  Offline
Member
Joined: Apr 2002
Posts: 914
Alpharetta, GA
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.


#27415 - 07/14/03 11:29 PM Re: Update on the "HOT" water & question  
nesparky  Offline
Member
Joined: Jun 2001
Posts: 642
omaha,ne
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


ed

#27416 - 07/14/03 11:55 PM Re: Update on the "HOT" water & question  
PCBelarge  Offline
Member
Joined: Jun 2003
Posts: 681
Dobbs Ferry, NY, USA
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


Pierre Belarge

#27417 - 07/15/03 12:14 AM Re: Update on the "HOT" water & question  
ThinkGood  Offline
Member
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
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).]


#27418 - 07/15/03 07:35 AM Re: Update on the "HOT" water & question  
sparky  Offline
Member
Joined: Oct 2000
Posts: 5,303
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.....


#27419 - 07/15/03 08:11 AM Re: Update on the "HOT" water & question  
PCBelarge  Offline
Member
Joined: Jun 2003
Posts: 681
Dobbs Ferry, NY, USA
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


Pierre Belarge

#27420 - 07/15/03 10:35 AM Re: Update on the "HOT" water & question  
Ichabod  Offline
Member
Joined: May 2003
Posts: 26
Statesboro, GA, USA
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?


#27421 - 07/15/03 11:02 AM Re: Update on the "HOT" water & question  
ThinkGood  Offline
Member
Joined: Aug 2002
Posts: 1,081
Milwaukee, WI
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.


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