I have a 5 volt charge on my copper water lines in my home and anything attached to the pipes. Its not enough to shock me, but was found when a metal flex gas line was touching a water pipe on my hot water heater. It had arched between the lines enough to burn a small hole in the gas line and flash up shaking the whole house. Gas line was unhooked and have no charge on gas lines now, but no water heater. I have had the electric company out twice, 2 master electricians, gas company, water company and even the cable company out. Not one of them can find the cause. The electric company even cut the wires coming in to the house from the service head and pulled the meter to check if it was their problem. With no power attached to the house, it was still showing the 5 volts on the water lines. Someone suggested it is EMF inducing a voltage in the pipes and replacing a foot of the copper coming into the house from the service with a pex line might open the circuit. I don't know and need some advice, I have a plumber coming out this week to talk about it. As of now its been 2 weeks without hot water and no one can help me.

 

Is your plumbing grounded to the service panel?

 

no its not, its an old house 1940s.........one of the electricians, tried running a wire from a copper pipe to the electric meter ground outside as a test and it still showed the voltage

 

Is a digital meter being used to measure the voltage or an analog meter? And how is the voltage being tested?

 

both have been used and several different ones by all the people who have been here to check it

 

Voltage is a difference of potential. Between what two items are you getting 5 volts? (IE: reading voltage between the water pipe and ground wire or between the water pipe and the gas pipe)

 

voltage between any ground (any outlet neutral, the ground wire outside buried in the earth) and the water pipes or anything connected to water pipe (sink, outside faucet etc) There was voltage in the gas lines only when it was making contact with the water pipe.

 

Where are you measuring the voltage with no power to the house? When the POCO cut the service did they also cut the neutral at the same time?
Geo

 

between any copper water line or something connected to water line and the earth ground (wire coming off service meter outside buried into the earth. I just know a little about electricity, but same results from all the experts out to check it is frustrating me and costing me a lot of money. I appreciate the replies from everyone.

 

Has anyone checked that the neutral is well bonded to ground at the service disconnect.

 

Yes, electric company techs and 2 electricians so far

 

Could be an open neutral in a neighbour's house. It would then send their neutral current out the water lines to be shared by all houses in the area.

 

Hey thanks, do you think a foot of PEX line to replace some copper would open the circuit to my house? I know tap water conducts too, but has to be less than copper

 

It might but electrical code requires you to jumper over that pex to bond the metal incoming water line and metal pipes in your house.

 

I wonder if bonding it to the electrical service earth ground would work instead of that jumper? copper pipe in from service connected to pex and the other end of pex connected to the electric earth ground. In other words, house pipes grounded to something other than the incoming water pipe

 

Any house, regardless of its age, should have the electrical ground bonded to the metal water piping. The connection to the underground water pipe acts as an earth ground as well (which nowadays is supplemented by a pair of 8' copper ground rods). Additionally, the gas piping should be bonded to the same ground via the furnace or water heater.

Once you correctly bond the electrical panel to the water system - and confirm the gas piping is bonded. Also bond the cable tv and phone lines... then everything should be at the same potential.

 

Hi, CSST (flexible gas line) has specific bonding requirements required by mfg.
http://www.csstsafety.com/Images/CSS...h-Bulletin.pdf
Geo

 

The POCO needs to cut power to your neighbors also. Then take the pipe to earth voltage measurements. As typed above, something like a neighbors defective water heater or an open neutral at their service can "inject" significant metal water piping currents to all neighbors sharing the water supply.

 

Turn off your main breaker and put a clamp ammeter around your incoming water service line. If there is any significant current measured, then there is some proof of a problem in the power grid or your neighbor's house that is feeding back through your service. If no significant current is measured, it isolates the problem to something in your service or your house.

 

I found it easier to understand the problem once the parenthesis were removed. Since ground to water pipes is giving you a voltage the water pipes are at a different potential than ground. As others have already stated, you have some additional grounding and bonding to do. I agree that the problem is probably coming from a neighbor's system and believe you may have to coordinate between your power company and a good electrician to locate and isolate the problem.

 

I agree you need to bond your water service to the electrical service. Then there will be no difference of potential.

I also agree that something is back feeding.

 

One advantage of hiring a professional is that he knows (should know; there is a higher probability that he knows better than you know) which tree to bark up first.

Part of the analysis is isolating things to help find where the current leakage is coming from. Turning off your main breaker is one step to take early. If the voltage discrepancy goes away then you know that leakage is coming from something in your house.

Yes your tests should include unhooking the grounding electrode conductors from ground rods and water pipe. This is not foolproof because there might be another path from electrical ground to exiting water pipe such as through an electric water heater .

Some point must be chosen as zero volts reference. Usually it is the house electrical ground.. Electrical ground begins with the neutral of the service wires entering your main panel. Equipment grounding conductors and grounding electrode conductors propagate the electrical ground. Unfortunately even it is not totally foolproof because there might be a bad connection back to the pole transformer. When you have a good and proper neutral to the pole transformer then any ground potential caused by problems at a neighbor's house should be dissipated.

I often suggest getting a long wire, attaching one end to the panel neutral bus bar, and stretching the wire upstairs to where you are doing testing, using that wire as the zero reference, where one of your meter probes is always attached when you do voltage measurements.

 

Hi, some folks have mentioned that it could be feed back from a neighbor. I would think that feed back would affect other neighbors also, why not check to see if other neighbors have the same problem? That may help trouble shooting the problem.
Good Luck Woodbutcher

 

I suggested unhooking the grounding electrode conductor from the main water pipe only for the purpose of finding out whether the voltage is coming from outside the house via the water pipe coming in. This should only be done for a short time and the GEC reconnected when you are done testing.

Assuming your service neutral has not failed, when the GEC is connected or reconnected to the water pipe the elevated voltage on the water pipes should disappear.

IMHO, if you determine that the elevated voltage is coming from outside the house via the water pipe then reconnect the GEC, see the elevated voltage disappear, and forget about it. I do not think it is necessary to research any neighbor's electrical system.

 

But if other neighbors have their pipes bonded to neutral(electrical ground), there should still be no voltage difference between the pipes and neutral (electrical ground), should there?

 

If all you pipes are bonded together and to the neutral you will not be able to measure a voltage on them. You could possibly measure a current but you will only get voltage if you break the bond somewhere.

 

You would see a division of the current and between the various ground & neutral paths inversely proportional to the impedance of each path. Even small differences in each electrical path through the pipes might cause a big difference in how much residual current shows up in each of the neighbors' houses. This type of problem can be pretty hard to diagnose and will likely require a coordinated effort on site with a power company lineman.

 

If there is 5V on your pipe, then the neighbor who has open neutral would have outlets with at least 5V less than normal.


Can this be used to find the house with the open neutral -- measure each neighbor's main's voltage (an outside outlet would be easiest) and see who has voltage that's 5V or more below the norm.


Of course the 5V can vary depending on how much power the open neutral neighbor is using.

 

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This is not a solution but more data. Local power company PSE&G uses plastic for gas line from street main to gas meter at house. From meter into house mine is all black steel pipe.

Have never looked for voltage on interior house gas lines. If voltage did exist would suspect due either to contact with house wiring or galvantic action, especially if line from street to meter was metal, not plastic.

Would turn off main panel circuit breaker and check for voltage.

Because of lightening issues here I have separate 3/8" X 8 foot copper earth ground rod connected to electric panel ground. There is also panel ground wire from water meter.

Separate residential building electric systems should be independent of neighbor's systems except for line voltage variations and transients.