Stray Voltage

[mtnelect]

How about "NWV" Neutral to Water Voltage. If you ever had a boat docked at a marina you know about Zinck Plates if you have a wooden hull. We had a 44-foot sloop moored at Marina Del Ray and every year we noticed the Zinck Plates eroding faster and faster as more and more people started living on their boats. Just another interesting phenomenon of electricity in this case electrolysis.

One day we came back from a day of sailing and sitting on the stern enjoying a steak of a hibachi with a few drinks ... We noticed the motor sailor suddenly raise out of the water and the mooring ropes became taught. Later we found out the keel dropped off !

 

[hornetd]

This monolithic slab has 2' wide, 4' deep footers that are in direct contact with the earth and should be at ground potential. If the ground rod was effective, it should also be at ground potential. Therefore, though not bonded together physically, the slab and the electrical system should be at the same potential.

Sometimes the slab is tied to the footer but not always. For reasons that can only be found in the hearts of architects some of the slabs are supposed to "float." If the slab and the footers are in fact monolithic AND the footer reinforcing steel has been bonded to the separate ground bar that you said had been installed, as the code requires, you need to do another test. It is the ultimate test of whether the problem is the utilities or yours. If you open the Service Disconnecting Means and you still have current flowing on the Grounding Electrode Conductor (GEC) the current is coming from the utilities system. If opening the Service Disconnecting Means cuts off the current flowing through the GEC then the problem is on the load side of the Service Disconnecting Means and it's all yours. Let me be clear that the GEC, in your case, is the single conductor between the Service Disconnecting Means and the Ground bar that you said was installed. All of the conductors between that ground bar and the individual grounding electrodes are electrode bonding conductors. If you did not mean to say that a separate ground bar was installed outside of the Service Disconnecting Means enclosure then that's all wet and can be completely ignored.

Tom Horne

 

[hornetd]

(POCO usually frown on you doing anything around their system. They might even call it trespassing.)

They might indeed "call it trespassing" but when they do they are blowing smoke. The utility's "right of way" is an easement for the specific purpose of delivering electricity to customer premises. The easement is on either public or private property and the ownership of that property is unchanged by the existence of the easement. Property owners and their welcomed guests are legally incapable or trespassing on their own land or on public land which has not been statutorily reserved for a specific use. In some states there is no public property in most neighborhoods. The streets in those states are public easements over land which belongs to the property owners on either side of the street. Their property line meets the property line of the property across the street in the middle of the road or street. The reason that the property owners have no control of that portion of their property is the public easement which anyone has the right to pass over, at any time not otherwise prohibited by law, such as an emergency curfew. The long and the short of it is that no one is capable of either civil or criminal trespass on public land which is not reserved for a specific use nor forbidden to use by the general public nor by passing over a public easement. The only way to trespass on the utilities property is to be supported off of the surface of the ground by the utility owned outside plant. As for taking measurements that isn't trespass either but it can be tampering with public utility property if you disarrange the conductor you are trying to test. Using a magnetic field sensing coil without prying the conductor off of the pole or otherwise changing it's relationship with the utility's other equipment is not tampering and it certainly isn't trespass. Now if you were to cut the transformer's grounding conductor in order to insert a metering shunt into the wire pathway that would definitely be tampering with utility equipment.

Example: Pacific Gas & Electric (PG&E) has an easement to pass through some property owned by my church in the Santa Cruz mountains of California. The original easement was to the Bell Telephone Company which the state of California allowed them to cede to Pacific Gas and Electric without having to obtain a new easement. That was done because electrical distribution requires much taller poles and Bell's existing pole setting equipment was not up to the job. Bell Telephone made an arrangement, again with the consent of the State Legislature to pay a maintenance charge for the use of the telephone poles to support their wires also but that was the last intervention by the State. Thereafter any perspective user of the easement had to negotiate a new one with both the property owners and the 2 public utilities. I was on the church committee that managed the property and it's primary use was as a retreat center for church members and congregations by arrangement with the resident caretakers. During a work day on the property the caretaker lamented that the local cable television provider would not provide them with service. They could only receive one station after an aerial was place in the top of a 100+ foot redwood tree. I looked up at the pole line which passed through church property on one of the historic converted easements. Spying a large cable which was obviously very low loss coaxial cable I took a rather long hike following that pole line. When I reached the ridge line some 3 hours later I found the cable television company's satellite down station which provided television content from satellites to the cable providers network. Their distribution hub was situated in the valley below. The cable was continuous between those 2 points. It did not serve any individual premise with cable television service. I visited there offices with another member of the committee, who was an attorney and a member of the California Bar. I just stood back and watched the smoke while he quietly and calmly burned that company down to it's ankles. He pointed out to their manager that the easement that they had obtained from PG&E had no basis in law because PG&E could not grant rights over property they did not own and it was already black letter law that the holder of an easement cannot share their right to pass with another. Rights to the use of an easement of any kind can only be granted by the owner of the property or by the taking of the easement by imminent domain. Some State constitutions do not permit the taking of a property owners rights by imminent domain except by the purchase of the entire property and California is one of those States. The cable company had absolutely no hope that the State would condemn all of the land over which the PG&E easement passed to provide the cable company with pole access. Later court decisions complicated such matters immensely but that was the situation in the late 60s. My co committee member brought in another attorney who specialized in communications law and between the 2 of them they obtained a repayment of all the easement income from PG&E to the church. They also negotiated a new easement agreement with the cable television provider which included the provision of free cable service to all of the residential and common buildings of the retreat center. I was very gratified to see the cable company's wiremen running the additional cable required down the pole line. They were at least smart enough to offer service from that line to all of our neighbors for which the neighbors were very grateful. Do keep in mind that, at that time, all a cable company did for you was provide television and radio service. The internet had yet to be born from the union of ARPANET and a couple of European systems.

 

[hornetd]

It is wrapped several times around the pole butt then buried.

Not always. That was the technique used by generations of lineman but there are now some others. One is to wrap the base of the pole in copper sheeting and connect the ground conductor to that. It's obvious advantage is the greater area of the cooper in contact with the soil. In many areas they have been using driven rods because the water table does not reach the but of poles buried 6 foot deep. single 10 foot 3/4 rods with some stacked in order to reach the local water table are also being used. I suspect that there are more ways that electrical utilities are grounding their neutrals but I don't happen to know what they are.

Tom Horne

 

[hornetd]

Potential ramps are cool and an ingenious way to keep cattle from getting zapped when entering a grounded building located far away from the substation.
My only goal was figuring out a way to equalize the potential between the kitchen floor and the kitchen appliances without destroying anything or costing a lot of money.
Not concerned with the step potential outside the home. That can only be solved when the problem causing the issue is identified. (POCO, neighbor, or distance from sub station)
If a ground ring can't do that, then I'm in agreement with electrician #2. Rip out the concrete floor and fix the issue with the slab bonding.

If the slab and footer is monolithic that is totally unnecessary. It's all bonded together already by the ordinary steel wire ties used in it's construction. In newer construction the slab is poured on top of insulating panels and is therefore not in direct conductive contact with the earth and cannot be used as a Grounding Electrode. The footers however, even if the footers and slab were poured as one piece so as to become monolithic; meaning a single stone; are very unlikely to be insulated at all. Basement walls are now usually insulated but footers? Well I've never seen it done in 45 years in the craft.

 

[Sea Nile]

If the slab and footer is monolithic that is totally unnecessary. It's all bonded together already by the ordinary steel wire ties used in it's construction. In newer construction the slab is poured on top of insulating panels and is therefore not in direct conductive contact with the earth and cannot be used as a Grounding Electrode. The footers however, even if the footers and slab were poured as one piece so as to become monolithic; meaning a single stone; are very unlikely to be insulated at all. Basement walls are now usually insulated but footers? Well I've never seen it done in 45 years in the craft.

The fact that the OP is getting tingling sensation when touching an appliance while barefoot in kitchen, and they measure a difference in potential, is proof that the slab is in direct conductive contact with the earth.

He also stated that it has rebar and it is not bonded to the grounding system.

Regardless of whether it's a code requirement to bond it or not, or whether it's considered insulated or not, bonding it would remove the potential and make him happy.

I'm not doubting what you say is true in most cases, but the evidence doesn't lie in this case.

If this were my house, I would not want to feel electricity when I touched my appliances and would bond it no matter how many people say it's not a code requirement.

 

[wclark160]

Hello everyone thanks for all of the help associated with this. A utility engineer came out yesterday and provided the following-
Neutral Earth Voltage is high due to being on the end of a single phase primary.
This was concluded after multiple test including a three point test, XFMR inspection, home wiring inspection, primary line/tap inspection. Once he mentioned NEV, he said the best way to mitigate was to bond the slab. SO, I immediately got out my hammer drill and Jack hammer and began chipping from the lower side! It was like it was meant to be because within about 30 minutes…I had a piece of rebar exposed with minimal slab work. I bonded to my ground rod and now voltage is essentially non existent. Where it had gotten as high as 12 volts just prior to bonding, it went to .2 volts after bonding. Thanks for everyone’s help.

 

[Sea Nile]

Hello everyone thanks for all of the help associated with this. A utility engineer came out yesterday and provided the following-
Neutral Earth Voltage is high due to being on the end of a single phase primary.
This was concluded after multiple test including a three point test, XFMR inspection, home wiring inspection, primary line/tap inspection. Once he mentioned NEV, he said the best way to mitigate was to bond the slab. SO, I immediately got out my hammer drill and Jack hammer and began chipping from the lower side! It was like it was meant to be because within about 30 minutes…I had a piece of rebar exposed with minimal slab work. I bonded to my ground rod and now voltage is essentially non existent. Where it had gotten as high as 12 volts just prior to bonding, it went to .2 volts after bonding. Thanks for everyone’s help.

I'm very happy it worked out!
I'm also an apprentice and I have learned so much just from following this forum.

I hope you stay on here and good luck.

-Sea Nile

 

[Fred B]

Hello everyone thanks for all of the help associated with this. A utility engineer came out yesterday and provided the following-
Neutral Earth Voltage is high due to being on the end of a single phase primary.
This was concluded after multiple test including a three point test, XFMR inspection, home wiring inspection, primary line/tap inspection. Once he mentioned NEV, he said the best way to mitigate was to bond the slab. SO, I immediately got out my hammer drill and Jack hammer and began chipping from the lower side! It was like it was meant to be because within about 30 minutes…I had a piece of rebar exposed with minimal slab work. I bonded to my ground rod and now voltage is essentially non existent. Where it had gotten as high as 12 volts just prior to bonding, it went to .2 volts after bonding. Thanks for everyone’s help.

Not sure how accurate the statement of being at the end of the run is. Glad you have reduced the apparent voltage at the slab, this would be expected of NEV issue, but the underlying cause issue remains.

 

[Hv&Lv]

I agree with Fred above. There is still an underlying problem.
I work for a utility and we don’t have NEV problems at the end of a long single phase run as long as all the connections on the pole are good.
You sure he was an engineer or someone that was a service man in the engineering department?
Glad something worked. As long as it’s quit for you that’s good.

 

[don_resqcapt19]

Hello everyone thanks for all of the help associated with this. A utility engineer came out yesterday and provided the following-
Neutral Earth Voltage is high due to being on the end of a single phase primary.
This was concluded after multiple test including a three point test, XFMR inspection, home wiring inspection, primary line/tap inspection. Once he mentioned NEV, he said the best way to mitigate was to bond the slab. SO, I immediately got out my hammer drill and Jack hammer and began chipping from the lower side! It was like it was meant to be because within about 30 minutes…I had a piece of rebar exposed with minimal slab work. I bonded to my ground rod and now voltage is essentially non existent. Where it had gotten as high as 12 volts just prior to bonding, it went to .2 volts after bonding. Thanks for everyone’s help.

I would have asked the utility to either install one of theses

BLOCKER® Stray Voltage Isolator

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ronkelectrical.com

of make the required modifications for you. This is a problem of their making, and then need to provide the fix.

 

[winnie]

I think I mentioned this in my original post, but now that you've used bonding to eliminate shocks inside your house, be on the lookout for shocks outside of your house, in particular at things such as hose bibs and the like.

Good job on solving the first problem.

Jon

 

[hornetd]

The fact that the OP is getting tingling sensation when touching an appliance while barefoot in kitchen, and they measure a difference in potential, is proof that the slab is in direct conductive contact with the earth.

It is not proof that the SLAB is in "direct contact with the earth." It only suggests that some part of what the OP described as a monolithic slab and footer is in contact with the earth. The most likely place that is true is the footer. I am only trying to suggest that it may not be necessary to "remove the kitchen floor" to remedy the problem. If the bonding of the reinforcing steel in the footer was not done and the OP is correct about the slab and footer being monolithic then bonding the footer steel to the Neutral conductor would be curative. It will not eliminate the Neutral Earth Voltage but it will shift the difference of potential to the outside of the home so the OP will stop perceiving it as a shock due to touch potential on the refrigerator. Making that bonding connection from outside the home will be less work and less disruptive of the family's life. In a slab on grade home the footer is not buried very deep. It will only be deep enough to be below the frost line.

You can force the utility to correct excessive NEV, but it will often require a lot of work and complaints to the state agency that regulates power utilities.

Don's is the best answer which is likely to be fully curative.

Your first step is to file a complaint with the enforcement authority of your State's utility regulating body. A call form them to the utility usually gets a response because the regulatory body has to approve the utilities requests for rate increases and part of that process is an evaluation of the quality of service provided by the requesting utility.

Should the State's utility regulators be unresponsive find out if your State local representative serves on the Public Service (Utility) regulatory board or commission. If your local representative or delegate doesn't serve on the utility regulatory body then find out if your State Senator; or whatever your State constitution calls members of the legislature's upper house; does. Representatives serve fewer people and so are often more responsive. Senators serve more people and have more clout. If either of their aids who handles constituent complaints call the enforcement office of the utility regulatory body of your State's government they will not be ignored. I have initiated this process 2 times in 45 years in the craft. In 1 case it took a call from the local representative to shake things loose. In the other the initial complaint was acted on with admirable speed.

Tom Horne

 

[hornetd]

and began chipping from the lower side!

Did you mean from underneath the kitchen floor? What did you mean to tell us by using the phrase "from the lower side."

 

[Mr Gary]

I can tell you that stray voltage is real. Many years ago I was called because cattle were getting shocked at the watering trough. Long story short, approximately 1/2 mile away at a farm house, they had inadvertently connected the 120V line to the wrong cable going to the well. 120V connected to the casing. Correcting this corrected the problem. Needless to say they had a high electric bill. I used a similar test previously mentioned, (probe in the ground), getting higher voltages as I got closer to the house.

 

[ActionDave]

I can tell you that stray voltage is real. Many years ago I was called because cattle were getting shocked at the watering trough. Long story short, approximately 1/2 mile away at a farm house, they had inadvertently connected the 120V line to the wrong cable going to the well. 120V connected to the casing. Correcting this corrected the problem. Needless to say they had a high electric bill. I used a similar test previously mentioned, (probe in the ground), getting higher voltages as I got closer to the house.

How was it possible for the well pump to operate? Seems like someone at the farmhouse would have noticed they had no water.

 

[Sea Nile]

I can see it. If it casing was not bonded with an effective path back to the source it wouldn't trip the breaker. So the parallel path back to the source would be both the neutral and the ground rod/earth, pump should still work.

 

[Sea Nile]

I can see it. If it casing was not bonded with an effective path back to the source it wouldn't trip the breaker. So the parallel path back to the source would be both the neutral and the ground rod/earth, pump should still work.

Sorry, thinking about it I want to change my comment. The correct cable had to be connected or the pump wouldn't work like you said @ActionDave . But there must have been a short from the ungrounded conductor to the case

 

[Sea Nile]

Sorry, thinking about it I want to change my comment. The correct cable had to be connected or the pump wouldn't work like you said @ActionDave . But there must have been a short from the ungrounded conductor to the case

Or maybe it would work, after all, a light bulb still works when it's wired backwards. The only thing I know for sure is the case was not bonded back to the source and the hot was touching the chassis.

 

[bobby ocampo]

What are the root cause of this touch potential? What is the system voltage? What are the possible ways why the enclosure is energized?