Stray Voltage in Pool / EGC

[dennis schaffert]

stray voltage

stray voltage

I do not know if this is still an on going problem but non the less I find it interesting.
From what I understand you have turned off the primary source of power and still have the problem and you have indicated that there may be the possibility of induced current from UG communications.
If I may suggest some possibilities, my first concern is that the pool ground seems to be a vector right away for the voltage to travel because it is the route of lowest impedance and resistance or is the greatest source of opposite potential. in theory this suggests that the service grounding electrode and or the pole mounted electrode have a high resistance indicating the need to add grounding or provide a better connection to the grounding electrode by providing a more effective ground up stream so to speak. You are providing a new path to ground of higher potential for the current to follow.
Step one only provides a new path but does not eliminate the source.
Secondly I would look for the source as being from one off the following connections made to the grounding system from a third party source, such as telephone system grounding with in the facility, Cable TV company grounding and possibly water or gas company.
Your power may not be the source but because the grounding system is shared in most cases this is the cause, it could be as simple as one phone ground.
Because you have already eliminated so many of the possibilities you have already reduced the problem to two facets the first is. Electricity is all about potential , the highest positive wants to flow to the lowest negative potential , its always trying to find equalization, the pool area seems to be the lowest, provide a better low potential and you have re routed it

Your second problem is source and it appears you have ruled your self out so look for a third party source.
Dennis

 

[petersonra]

since disconnecting the egc eliminates the voltage, it makes me wonder if there is some N-G connection in the house that should not be there.

 

[dennis schaffert]

stray

stray

Even with a second bond between neutral and ground somewhere in the house it would not change the fact that the pool ground seems to be acting as the path that the stray voltage migrates to meaning it has the highest opposite potential than the source current.
The only other most remote possibility would be due to some high mineral content or substance in the pool its self, acting as a solar voltaic cell consequently making it the source. Although unlikely it is possible.
The cause is most likely a third party ground attachment

 

[dennis schaffert]

I should add that disconnecting the ECG does not eliminate the voltage, you are simply interrupting current flow by opening the grounding circuit.
In that instance the voltage will still flow to the next lowest opposite point of potential . Unless its the pool

 

[don_resqcapt19]

Dennis,
I really don't understand. Electricity doesn't flow like water to a low spot as you seem to be saying. It only flows back to its source via all paths that are available.
Don

 

[dennis schaffert]

Don,
If I may explain, In the early 19th century up to about the thirties Voltage was characterized as pressure and current as flow, very much like a fluid in a pipe. The higher the voltage (IE pressure )the greater the distance that power ( IE current )will flow, Hence why transmission lines are of a higher voltage but a much lower amperage. Know I am trying to keep this simple.

To convert that high voltage to usable current inductive transformers are employed to lower the voltage and increase the amperage.

Do to the cost of constructing the new electrical systems of that time, the practice was to employ ,a single high voltage conductor only, suppling power to the transformer, this was a cost effective method ,no neutral or return wire was installed back to the source.

The question then arises how did they provide a return? Now we know that current will not flow unless it has a path theoretically back to its source, and one might ask why is that? Consider the supply as a positive charge with some given potential, Pressure/ voltage and we will consider the negative/ neutral as an equal or greater negative charge opposites attract and like charges repel . When you provide a path connecting these opposite charges a flow of electrons occurs in your conductor. The practice was to provide a ground on the opposite side of the primary of the inductive transformer and bond the negative side of the generator to ground , hence completing the
circuit through the earth.
I understand this practice is still used today.

Simply providing voltage to a circuit does not create the flow of power. It does not push it through the conductor it only provides the pressure for it to flow. it is the unequal potential of charged particles that cause it to flow.

For the same reason a capacitor will only charge to a given point. when the potential difference between positive and negative become equal it stops charging.

I illustrate the current situation We understand that voltage is present or flowing at the pool the pool being the point of lowest negative potential charge. evidenced by metering voltage at that point.

We then have to determine the point or source of positive charge. Considering that the power was turned off, we can assume that a second source of positive potential is present. It could be a induced positive potential( High Voltage magnetically induced) or it could be an applied positive potential ( phone company / cable company )

Now if that connection provides a more direct path via the pool to ground or the negative potential, rather than the ground rod at the service or pole your going to meter voltage there. Exactly as he is.

Does this explanation help?
Dennis

 

[dnem]

Simply providing voltage to a circuit does not create the flow of power. It does not push it through the conductor it only provides the pressure for it to flow. it is the unequal potential of charged particles that cause it to flow.

For the same reason a capacitor will only charge to a given point. when the potential difference between positive and negative become equal it stops charging.

I don't understand your point in the first sentence.
"voltage to a circuit does not create the flow of power"
"it is the unequal potential of charged particles that cause it to flow"
The problem with these 2 sentences is that one good definition of voltage is the unequal potential of charged particles.

So what I'm reading is:
voltage [which is the unequal potential of charged particles] to a circuit does not create the flow of power.
it is the unequal potential of charged particles [which is voltage] that cause it to flow.

Those 2 sentences both can't be true.

I illustrate the current situation We understand that voltage is present or flowing at the pool the pool being the point of lowest negative potential charge. evidenced by metering voltage at that point.

The pool can't be the lowest negative potential charge. . The lowest potential charge is one side of the source generator or transformer. . An electron leaving one side of the generator or transformer is heading to the other side. . So the other side of the generator or transformer would be the most extreme potential for that electron and all of its buddies that make up the current flow. . All other points are just paths. . The electrons are just passin thru.

The only known fact is that the pool is in the path. . How the path is configured is unknown. . The path could be ground, pool, ground. . The path could be ground, pool, equipotential bonding wire to the motor enclosure, equipment ground wire, etc. . Or the path could be something else.

But the pool is definitely not the lowest potential charge.

David

 

[dennis schaffert]

Voltage

Voltage

Sorry for the slow reply but its fair time.
Voltage is defined as electromotive force EMF. It is the force that pushes the electrons through a wire and is often refereed to as electrical pressure.
A volt is the amount of potential necessary to cause one coulomb to produce one joule of work.
I incorrectly used the word voltage and should have used current in my illustration because to say voltage flows through a circuit would be saying that pressure flows in a water pipe
Voltage can be defined as potential force or energy it has the ability to push but can not be defined as an energy in motion it is equal to static pressure in a water pipe.
In creating an electrical circuit you must have a difference in potential positive and negative looking at a typical wave form the high side of the wave has a positive potential the low side has a negative potential regardless of its frequency.
In a closed loop circuit from the generator, lets assume that as current leaves a stationary point as positive, it creates a deficit of electrons at that point ,that we will consider as negative. if the system were completely closed say, the positive out put of the generator connected to the negative of the generator we would call this a shunt. most importantly we have created a flow of current positive to negative.
Now lets consider that we do not want to go through the expense of taking a conductor all the way out a mile and back again to the generator , we produce a larger EMF Voltage, produce more pressure and we terminate a single conductor into one side of an inductive coil or transformer the opposite side of that primary coil is then tapped to ground the earth the ultimate negative potential. we also bond the negative of our generator to the earth both then having connected to them a ground potential ,current begins to flow.
As the current flows through the coil we again produce a EMF field that induces a voltage on the secondary coil having a different number of turns reducing the voltage and increasing the amperage.
We have an isolation of the two systems primary and secondary at this point because there is no physical connection , only a magnetic coupling between them.
At this point we have now introduced a closed loop of electron flow on the secondary of the transformer and we again bond our neutral to ground. The transformer being the source of power or positive potential. We have now placed a ground potential on the transformer secondary and lets consider this potential to be negative. The question is what has the greatest negative potential the earth or the neutral conductor. Lets assume that the neutral does. the wiring is good and connections are secure we should have no flow of current to ground.
Now lets assume the neutral is going bad or there is a bad connection. the current will follow the path of least resistance to ground or negative potential.
Some times this is a water pipe and some poor plumber gets electrocuted when he replaces the water meter. Why did it not go to the ground rod obviously the pipe had a larger negative potential than the ground rod.

Considering the original problem we see that current is flowing to the pool and lets say that a phone ground is tied some were in the ground circuit with a 3 volt potential that source of power is independent of the power source of the house and is not induced to use the negative of the trans former a foreign power source as a return.Where does it go it follows the path of least resistance to ground . In this case the pool.

I do not believe in the concept of stray voltages or current, it is theoretically impossible, they can only be induced or applied the question always is the same, from were.
Hope this helps Dennis

 

[don_resqcapt19]

Dennis,
How is there a negative or positive potential on an AC system?

the current will follow the path of least resistance to ground or negative potential

No the current will follow all paths back to its source.

Considering the original problem we see that current is flowing to the pool

No the current is not flowing to the pool, it is flowing back to its source. The pool may be part of the path, but it is not the source or destination of the current.

Some times this is a water pipe and some poor plumber gets electrocuted when he replaces the water meter. Why did it not go to the ground rod obviously the pipe had a larger negative potential than the ground rod.

No, the pipe has a better path back to the source so more of the current will flow on it. It has nothing to do with a "negative potential", whatever that may be.
Don

 

[George Stolz]

Now lets consider that we do not want to go through the expense of taking a conductor all the way out a mile and back again to the generator , we produce a larger EMF Voltage, produce more pressure and we terminate a single conductor into one side of an inductive coil or transformer the opposite side of that primary coil is then tapped to ground the earth the ultimate negative potential.

(snip)

The question is what has the greatest negative potential the earth or the neutral conductor.

(snip)

...the current will follow the path of least resistance to ground or negative potential.

Dennis, I agree with Don, this principle is entirely incorrect.

Alternating current seeks every available path back to it's source, in proportion to the path's resistance. I put this in bold because it is fundamental.

Cast the terms aside for a moment, and let's just deal with it simply. Voltage exists, and current exists. Getting the right label on one concept of electricity (i.e. voltage/current) is secondary to understanding where the power is going, in my opinion.

The earth is irrelevant in a 120V circuit. From the transformer's perspective, power leaves on the hot, travels through the load, and returns on the neutral. (Let's disregard for the moment that it turns on it's heels and reverses direction 120 times per second.) Some of the power may return by way of the grounding electrode at the base of the pole the transformer is mounted on, because it is a path; but the power's destination is the neutral, not the earth.

Some times this is a water pipe and some poor plumber gets electrocuted when he replaces the water meter. Why did it not go to the ground rod obviously the pipe had a larger negative potential than the ground rod.

No, that's off. The reason why more current would travel through the water pipe than the ground rod (in the event of an open or resistive neutral conductor at the service) is because the water pipe has a lower resistance to the earth (that the transformer neutral is connected to) than the ground rod's connection to the earth (that the transformer neutral is connected to).

Another aspect of your plumber's scenario, is that the metal water pipe is likely electrically connected to the neighbor's water service, which has a direct electrical connection to the transformer's neutral. Let me elaborate:

• Remove the neutral from the service in House "A", and turn on 120V loads.
• The service is connected to a ground rod at 25 ohms.
• The service is also connected to a metal water pipe electrode.
• The electrode is metallically, electrically continuous to the neighbor's house.
• The neighbor's service is directly connected to their water pipe.
• The resistance from house "A" service's neutral point, to the neighbor's service neutral point is .025 ohms.

With House A's neutral removed from the service, 99.9% of the current trying to get back to the transformer's neutral with go by way of the neighbor's water pipe and neutral. Only .1% will use the ground rod, because of the disproportionate resistance - the neighbor's neutral is 1000 times better than the ground rod.

Actually, the resistance of the ground rod (25 ohms in the example) is only part of the equation, because the resistance of the utility's connection is in series to my ground rod.

 

[dnem]

Dennis,
I usually try to ignore "shorthand" that uses phrases that aren't totally correct because we all use various types of shorthand such as calling a conductor a "wire" or calling a receptacle a "plug". . But when you lay out an entire electrical lesson on electricity 101, you need to be more careful in your choice of words.

In a closed loop circuit from the generator, lets assume that as current leaves a stationary point as positive, it creates a deficit of electrons at that point ,that we will consider as negative.

Electrons have a negative charge. . If there's a deficit of electrons, the charge would be positive

most importantly we have created a flow of current positive to negative.

Conventional current flow theory from the 1800s recognized current as flowing from positive to negative, but with the development of the electron microscope and other scientific advances, it was discovered that they had not been tracking the flow of electrons. . They were tracking the voids left by the movement of the electrons. . The voids moved positive to negative. . Actual electricity moved negative to positive.

Electron current flow is negative to positive. . The negatively charged electron moves toward the positive point of the generator or transformer. . If it could move thru the generator or transformer to get to that point it would but it is prevented from doing so by a magnetic field within the generator or transformer. . So the electron takes its other option which is to travel "all the way out a mile and back again to the generator"

Now lets consider that we do not want to go through the expense of taking a conductor all the way out a mile and back again to the generator , we produce a larger EMF Voltage, produce more pressure and we terminate a single conductor into one side of an inductive coil or transformer the opposite side of that primary coil is then tapped to ground the earth the ultimate negative potential.

You end this explanation that is primarily correct but contains some "shorthand" wording with a phrase that is completely wrong.

"ground the earth the ultimate negative potential"

That is completely untrue. . The ultimate opposite potential from one side of the source is the other side of the source. . The ground is a possible path and is never the ultimate potential.

At this point we have now introduced a closed loop of electron flow on the secondary of the transformer and we again bond our neutral to ground. The transformer being the source of power or positive potential. We have now placed a ground potential on the transformer secondary and lets consider this potential to be negative. The question is what has the greatest negative potential the earth or the neutral conductor.

You're intermixing alot of good electrical information with stuff that's off. . You mention "introduced a closed loop of electron flow" but then you say the "ground potential on the transformer secondary and lets consider this potential to be negative" when electron current flow states that it's positively charged compared with the electron. . The ground nothing more than another path. . It may be a better path. . It may be a worse path. . But even a worse path will conduct some current flow and the small amounts being measured on this pool could be from a number of sources.

David

 

[dennis schaffert]

Reply

Reply

Sorry for the slow reply again it is county fair time and my time is limited.
Well George,
Lets not stop here. You are correct current ( seeks ) every available path, although it follows the path of least resistance, this is text book. If you would like to include the term proportional as defining the highest or lowest resistance ? I consider the phrase as meaning the exact same thing.

Leaving the earth aside for the moment ,we are both in agreement that the current produced at the transformer ( Positive ) wants to return to its source ( negative ) Commonly called a closed loop circuit. You have also added in, one additional fundamental of current flow and that is a load. Again a fundamental requirement.
A question that I will set before you is, Hypothetically if the ungrounded conductor has a 120 V positive potential voltage and say a one hundred amps current potential. Does the Grounded conductor have an equal potential of 120 V Negative potential votage of one hundred amps? Or do you believe the Ungrounded conductor has a reduced potential do to the combined effect of the load and its Resistance etc. acting in the circuit

Moving forward from there ,concerning interconnecting water lines and the supposed ability for a bare, corroded, metallic, uninsulated conductor, hundreds of feet in length, having both a resistive element and an open conductance to ground bearing the ability to conduct current back to its source with a potential of 120 V or less.

I concur that the possibility may exist in a perfect scenario. And I can remember hearing such a story. Although in thirty years I have never encountered it , I have never met anyone that has and I have never seen any credible scientific evidence supporting this theory. Possibly you have something? I think the Myth Busters should try this one and possibly some one should throw in impedance as a additional element.

Lets try this one,
We have all encountered an open neutral and observed the effects on the ungrounded conductor . This condition is normally evidenced by random odd voltage readings on our meters or possibly a fluctuating voltage, inconsistent with the source voltage. Easy Button ! But in the case of a separately derived source AC or DC coupled via a single ground circuit, Mechanically connected , do all your rules apply? Do you believe that the separately derived sources destination in that ground circuit is induced to follow a path to the first source neutral negative point or will it find the path of least resistance to Ground independent of the first?

Lets consider that the earth ground is a constant, its negative potential is a set amount and does not change. On the other hand our transformers negative potential is an induced potential equal to the applied potential and because it is induced its negative potential is greater than that of the earths. We can assume that in this case the positive of the transformer will return to the negative of the transformer. lets call this a closed circuit and everything is operating fine.

Now lets add a load and open this circuit and apply a second source of negative potential ,less than the primary sources ,but none the less negative. Do you believe current will stop or flow to the secondary source?
So to speak we now have a open neutral now add in a separately derived source of power that does not have a return path. Considering that we now have two power sources and two open neutrals on one ground network having a constant negative potential what do you believe will be the result?

Change the scenario and consider your first source intact and your second source open, but having a much lower applied voltage potential and it is DC. Now turn the power off on your first power source and read your ground, will you read a voltage to ground or not?

Considering the original problem as I interpreted it, I pointed out a probable cause Based on encounter and theory. A potential answer to a complex problem with the possibility of a remedy ,your objection offers no probable answers, that would appear, have not been investigated.

 

[dennis schaffert]

Dave I have noted your comments and have illustrated using the conventional method out of simplicity .
I incorrectly used the term ultimate and should have used constant.
I do not disagree that the Ultimate destination is the source . What I have tried to show is the result when that return path is opened. And separately derived sources are present coupled to a common ground system
You have consistently described ground or earth as a path with out charge Neg or POS if I correctly have interpreted you.
Am I correct is this what you mean ?
And yes I think faster than I write
My intent is not a class electrical 101, My intent was to best describe current flow based on opposite polarities positive and negative and to often used potential in its place in trying to describe direction of flow I hoped to try to keep it simple and complicated it by the use of the wrong terms I will heed your advice and reread much more in the future.

Any way what do you want I own two business have seven kids ,attempt to do as much independent research as possible and just love electricity like the rest of us
Dennis

 

[George Stolz]

Lets not stop here. You are correct current ( seeks ) every available path, although it follows the path of least resistance, this is text book.

In my opinion, what you are saying is the equivalent of saying "Frank travels in all directions, but only travels north." This doesn't make sense, current either uses all paths, or uses one. If current sought only the path of least resistance, then your lights would go out if your A/C kicked on, because the resistance of the A/C is lower than your dining room light.

In fact, the whole nation would be trying to figure out how to get their hands on a 10,000W light bulb.

If you would like to include the term proportional as defining the highest or lowest resistance ? I consider the phrase as meaning the exact same thing.

In my opinion, considering proportions means considering all aspects of the proportion at the same time; so I care about the low resistances as much as the high resistances, to assign a percentage to where the current is flowing.

Leaving the earth aside for the moment ,we are both in agreement that the current produced at the transformer ( Positive ) wants to return to its source ( negative ) Commonly called a closed loop circuit.

I'm glad we agree on this principle, but why do you insist on assigning "negative" and "positive" labels to the parts? Why not just use common electrical language, or the language of the NEC? :-?

A question that I will set before you is, Hypothetically if the ungrounded conductor has a 120 V positive potential voltage and say a one hundred amps current potential. Does the Grounded conductor have an equal potential of 120 V Negative potential votage of one hundred amps? Or do you believe the Ungrounded conductor has a reduced potential do to the combined effect of the load and its Resistance etc. acting in the circuit

I believe it is Kirchoff's law that states that the current on all conductors of a circuit are the same. The outflow equals the inflow. The term "potential" is incorrectly being attached to "current" in the quote above. "Potential" is a term synonymous with "Voltage".

Moving forward from there ,concerning interconnecting water lines...

(snip)

I concur that the possibility may exist in a perfect scenario. And I can remember hearing such a story. Although in thirty years I have never encountered it , I have never met anyone that has and I have never seen any credible scientific evidence supporting this theory. Possibly you have something? I think the Myth Busters should try this one and possibly some one should throw in impedance as a additional element.

What aspect of what I described do you feel is incorrect? :-?

I've tried reading what you've written about transformers, but I honestly don't understand what you're trying to say after two read-throughs of what you wrote.

I will say this: the lowest potential that can be detected is zero. Measuring zero potential between two points means the same thing as reading zero volts between them.

All that zero potential means to us is that no current will flow between the points measured.