Woman Shocked in Shower by Stray Voltage

[brother]

Wouldn't the required bonding in the NEC prevent this type of situation? If the neutral was bad at the transformer, then the electrician would be able to isolated this I would think.
You think GFCI's are going to be required everywhere now just like AFCI's ?


What do you think of this story? Have any of you been called out to this type of situation?


Woman Shocked in Shower by Stray Voltage Wins $4 Million Lawsuit. Are You at Risk, Too?

http://shine.yahoo.com/healthy-livin...192310440.html

 

[GoldDigger]

Woman Shocked in Shower by Stray Voltage Wins $4 Million Lawsuit. Are You at Risk, Too?
http://shine.yahoo.com/healthy-livin...192310440.html

That should be http://shine.yahoo.com/healthy-livi...-lawsuit--is-your-shower-safe--192310440.html
http://shine.yahoo.com/healthy-living/woman-shocked-in-shower-wins--4-million-lawsuit--is-your-shower-safe--192310440.html

When you copy and paste the shortened form of the URL (what you see is not what you get) the link in the post will not work. If you copy the full URL from your browser address bar or "copy link" instead of just "copy" when picking up a working link from another web page, it should work properly.

 

[GoldDigger]

Wouldn't the required bonding in the NEC prevent this type of situation? If the neutral was bad at the transformer, then the electrician would be able to isolated this I would think.
You think GFCI's are going to be required everywhere now just like AFCI's ?

I doubt that either a GFCi or an AFCI would make any difference at all in this case. Proper bonding certainly might have prevented it. But only if the drain pipes were bonded as well as the plumbing.
And if the grounds were made to separate ground electrodes without proper bonding conductors between the ground rods, it might not have helped at all.

The whole allegation of "stray voltage" is a catch all for anything that has not been investigated well enough to determine the underlying cause.

Some possibilities in no particular order, and taking into account that the proximity of the substation might have something to do with it.

1. The shower piping was not grounded and had a voltage induced in it either capacitively or magnetically.
2. There was an AC wiring or appliance problem in the house which resulted in leakage to unbounded water pipes.
3. The shower pipe was grounded but the drain pipe was not, with either possibility 1 or 2 only the drain pipe.
4. Enormous ground currents related to the substation caused a voltage gradient near the surface which caused two grounds electrodes to be at different potentials.
5. A faulty service neutral bond could have caused the service neutral to deviate so far from ground that the local ground electrode bond could not pull it all the way to earth ground. This would leave a potential difference between metal which is grounded by earth contact but no bonded and metal which is bonded to the elevated ground electrode potential.

Any of these should be detectable, quantifiable and repairable.

I am sure other members will come up with other possible explanations, as well as opinions on the competence of the workers who tried to fix this.

 

[SG-1]

There have been several threads here concerning this subject.

Mike Holts 2008 Grounding vs Bonding Video has a special section on this subject.

 

[kwired]

There is "stray voltage" practically everywhere. It is installation practices that minimize exposure to it. There obviously was no solid bond between whatever surfaces she was getting shocked from, if there was there would be no potential between them.

With things like swimming pools we bond about anything you can think of to prevent such voltages from happening. When we do this, we don't get rid of the stray currents, we just "equalize" the potential between "touch points" to prevent current from flowing through people. This person obviously had voltage potentials between objects in her shower, and had she called a competent person to investigate this problem could have been solved, but not for 4 Million.

POCO obviously needs to hire a better lawyer.

 

[MarineTech]

Interesting article.

A few questions:

If voltage potential is due to substation grounding nearby, why did elevating the old shower make a difference?

How do EM fields factor into evidence when this is clearly a case of shock (AC current flow) and not induction?

Comments:

The plantiff asserts she is effected by AC current flowing through her body (Electric Shock). If so, this is easily verifyable at the shower. The current could be due to stray voltage (Gradients) or leakage (insulation breakdown).

I need more data, before identifying root cause.

FYI For basic AC leakage tests I use a Fluke 87V (uA AC Current range), or when a clamp meter is needed a Hioki 3283 Clamp On Leak Hitester.

 

[GoldDigger]

POCO obviously needs to hire a better lawyer.

Or a better jury. That is one of the things that an appeals court can deal with if they find that there was insufficient evidence to justify the award. The appeals court cannot override the jury on their findings of fact unless they are grossly unjustifiable to a reasonable person.

 

[GoldDigger]

Interesting article.
A few questions:
If voltage potential is due to substation grounding nearby, why did elevating the old shower make a difference?

My guess is that the elevation was not the issue, but the new water or drain piping was either non-conductive were the old was or was conductive where the old piping was not. It also could have been as simple as replacing a cast-iron tub with a fiberglass tub.

The usual reason for an elevated shower installation is that there was not enough room for the drain piping without trenching through concrete or earth or building a chase in the ceiling below, so we can assume that there was a substantial change to the plumbing.

 

[kwired]

My guess is that the elevation was not the issue, but the new water or drain piping was either non-conductive were the old was or was conductive where the old piping was not. It also could have been as simple as replacing a cast-iron tub with a fiberglass tub.

The usual reason for an elevated shower installation is that there was not enough room for the drain piping without trenching through concrete or earth or building a chase in the ceiling below, so we can assume that there was a substantial change to the plumbing.

Thanks for bringing that up, now the plaintiff can go after the plumber for another million dollars

 

[Speshulk]

In the past year we've had 3 different cases where we were getting stray voltage at the service location. The first instance was on the replacement of a burned up panel below the meter pan on a pole. I had almost everything disconnected with no issues, and then got belted as I was removing the ground wires from the panel. Once everything was physically taken apart, we took readings that fluctuated somewhere in the neighborhood of 600V between the meter pan cabinet and ground.

The second instance was on another upgrade. Didn't feel that one because I saw the arc between the ground wire and the romex connector as I tried to remove the wire.

The third was just last week on a generator installation. We were installing a 200 amp ATS beside the meter pan. As I was taking a measurement I felt a small tickle from my tape measure. 168V from the meter pan cabinet to ground.

I'm not sure what the remedy was in the second instance, since the POCO didn't have it figured out until after we left the job site, but in both the first and third instances, they installed new transformers and the problem went away.

 

[ggunn]

In a rent house I used to live in there was an aluminum frame window in the shower. I found out very quickly not to touch the window frame while I was standing ankle deep in water. I just treated it as a "don't do that" situation; I could have gotten $4M for it???? Dang!

 

[kwired]

In a rent house I used to live in there was an aluminum frame window in the shower. I found out very quickly not to touch the window frame while I was standing ankle deep in water. I just treated it as a "don't do that" situation; I could have gotten $4M for it???? Dang!

You could have sued the landlord, to get 4M you would likely need to develop some condition that there is no cure for.

 

[Speshulk]

In a rent house I used to live in there was an aluminum frame window in the shower. I found out very quickly not to touch the window frame while I was standing ankle deep in water. I just treated it as a "don't do that" situation; I could have gotten $4M for it???? Dang!

At the very least you could have complained about the slow drain.

 

[ggunn]

You could have sued the landlord, to get 4M you would likely need to develop some condition that there is no cure for.

Hmmmm. I have lots of those. For example, ever since that incident I am not able to play the violin. Of course, I never could before, either.

 

[GoldDigger]

Hmmmm. I have lots of those. For example, ever since that incident I am not able to play the violin. Of course, I never could before, either.

This one is back in the news again: http://forums.mikeholt.com/showthread.php?t=152897

From the description of problems outside as well as inside the home, I am beginning to think that no amount of grounding or bonding on the home property would have completely alleviated the problem. Installation of a full equipotential grid a few feet under the ground, over the entire neighborhood, maybe. Or at least within each affected property. And then be careful shaking hands with your neighbor across the fence.....
The earth potentials in the area of the substation were tremendous and variable!

And just to be a complete pessimist, taking extraordinary precautions in the immediate neighborhood would just have extended the problem further out, until you got beyond the "sphere of influence" of the substation. I would not be surprised if there is also some unusual geology involved that is making the earth conductivity different in horizontal and vertical direction.

 

[MarineTech]

This one is back in the news again: http://forums.mikeholt.com/showthread.php?t=152897

From the description of problems outside as well as inside the home, I am beginning to think that no amount of grounding or bonding on the home property would have completely alleviated the problem. Installation of a full equipotential grid a few feet under the ground, over the entire neighborhood, maybe. Or at least within each affected property. And then be careful shaking hands with your neighbor across the fence.....
The earth potentials in the area of the substation were tremendous and variable!

And just to be a complete pessimist, taking extraordinary precautions in the immediate neighborhood would just have extended the problem further out, until you got beyond the "sphere of influence" of the substation. I would not be surprised if there is also some unusual geology involved that is making the earth conductivity different in horizontal and vertical direction.

Gold,

In reading the background of the updated info per the link, for the lady in the shower, it states that AC voltage (3 VAC I believe) was measured in the shower. Would you have a guess as to where the AC Volt was measured? Between which two points exactly?

Thanks

 

[GoldDigger]

Gold,

In reading the background of the updated info per the link, for the lady in the shower, it states that AC voltage (3 VAC I believe) was measured in the shower. Would you have a guess as to where the AC Volt was measured? Between which two points exactly?

Thanks

From the description, I expect that it was measured between the water supply plumbing (specifically the valve handles and/or shower head and tub spout) and the drain in the bottom of the tub, since that would determine the voltage applied to the water.
That way the current would be flowing from one hand through both feet into the water, as described in another part of the article. But that is just a SWAG.

Note that that particular source of voltage should have been eliminated by proper bonding of the two parts of the plumbing system unless enormous ground currents were flowing through some part of the pipes.
If the drain was not specifically bonded anywhere, it could assume the local earth voltage somewhere in the area, up to the first non-metallic drain segment, while the water pipes are more likely to be pulled toward the earth voltage wherever the main grounding electrode was located.
If the water was not bonded either, it could be the potential of some point where a pipe contacted the earth.

 

[MarineTech]

From the description, I expect that it was measured between the water supply plumbing (specifically the valve handles and/or shower head and tub spout) and the drain in the bottom of the tub, since that would determine the voltage applied to the water.
That way the current would be flowing from one hand through both feet into the water, as described in another part of the article. But that is just a SWAG.

Note that that particular source of voltage should have been eliminated by proper bonding of the two parts of the plumbing system unless enormous ground currents were flowing through some part of the pipes.
If the drain was not specifically bonded anywhere, it could assume the local earth voltage somewhere in the area, up to the first non-metallic drain segment, while the water pipes are more likely to be pulled toward the earth voltage wherever the main grounding electrode was located.
If the water was not bonded either, it could be the potential of some point where a pipe contacted the earth.

Thanks for the reply.

Yes I think you are correct. AC current flow, from stray voltage potential, from the fixture to the water. It would have been interesting to measure the actual AC current from the fixture to the water.

In addition to your idea on large ground currents producing the voltage source, I think it could also be due to a earth voltage gradient from the sub station.

Best regards,

MarineTech

 

[GoldDigger]

Thanks for the reply.
In addition to your idea on large ground currents producing the voltage source, I think it could also be due to a earth voltage gradient from the sub station.

Best regards,

MarineTech

An earth voltage gradient from the substation must result from large earth currents flowing to/from the substation.
My concern was that even if there is a bond wire from one point in the plumbing to another, there could still be a voltage difference at the shower if the earth connections are causing large currents to flow in the bonding wire. This is possible especially if the bonding is undersized or compromised in some way.
If there are individual earth connections with a distance between them, and without a solid wire bond between them, that is guaranteed to produce a potential difference (and kill squirrels.)

 

[kwired]

An earth voltage gradient from the substation must result from large earth currents flowing to/from the substation.
My concern was that even if there is a bond wire from one point in the plumbing to another, there could still be a voltage difference at the shower if the earth connections are causing large currents to flow in the bonding wire. This is possible especially if the bonding is undersized or compromised in some way.
If there are individual earth connections with a distance between them, and without a solid wire bond between them, that is guaranteed to produce a potential difference (and kill squirrels.)

Bonding things together brings the potential down, especially to a level much lower than what contact across a person would lower the voltage. This will not make the stray currents go away, it just gives them a lower impedance path than through a person to flow through. Exactly what we do when bonding everything imaginable when constructing a swimming pool. We are not eliminating any stray currents we are just reducing points of potential within a specific area. Any EMF's associated with that current are still there, and possibly even increase to some extent since we made a lower impedance path which would allow more current to flow in that path.