Shock/Tingle getting into/out of pool

[nuttyp]

He did say he thought it might have a broken bond. From what he said, this seems to be his main thought. He tried several tests with a bond wire (his own) and my pool and handrails. It was 101 degrees here so we were all about to pass out.

Seems like this bond test is very key, when weather permits.

When you measured 4.5v to each rail, was that between each rail and nearby water? Or between the two rails? Always need to know the two points at which measurement was made. Whatever you wind up concluding about the source, it seems impossible to me that a potential difference (ie defined as voltage) exists between rail and water - or between rails for that matter - if the rails and water are truly bonded together.

Revisiting the source (which per above I still think is rather moot): You say it must be coming from the house panel, but have you run Mike Holt's tests, such as the resistance of the ECG from the pump back to the panel? Can only be done, as he states, with bonding wire and ECG disconnected at the pump. Have your guy do it if you're not comfortable with the pump wiring. Am trying to determine whether voltage is being induced onto the ECG (again that's the green ground wire) from your house wiring or from the power company. Another way to verify that is to run a new temporary ECG wire from the panel to the pump, temporarily replacing the present ECG to see if that changes things. If problem disappears, the ECG is suspect somewhere between the pump and the panel. It's simple enough for voltage to be induced onto the ECG as it travels from panel to pump - especially if there is high resistance in that ECG path - via a loose wire nut or unsecured screw to box, etc., anywhere in the path - and/or if that ECG travels a long path next to other active circuits sharing a conduit. In such a case your test results would also change from moment to moment, depending on the other circuit loads. Pop some toast in the toaster and suddenly you get a rail tingle. I spent a lot of my electronics engineering career - the boring part - analyzing and moving hundreds of circuit board paths to minimize parallel runs. I think you already proved that the problem persists even with all other home circuits disabled - such as with the main breaker off - so perhaps the parallel induction is unlikely. But the resistance of that ECG is still germane, and you can only get a valid test of it with other grounds and bonding disconnected.

Returning to the soapbox: Mike Holt's methodical test sequence is based on months of expert planning and experience by a team. If you wind up considering tearing up concrete before you've run through all the tests in his video, then I'll be siding with your wife about sanity

 

[Barry321]

Seems like this bond test is very key, when weather permits.

When you measured 4.5v to each rail, was that between each rail and nearby water? Or between the two rails? Always need to know the two points at which measurement was made. Whatever you wind up concluding about the source, it seems impossible to me that a potential difference (ie defined as voltage) exists between rail and water - or between rails for that matter - if the rails and water are truly bonded together.

I always test with one probe in water and one probe touching the handrail since that's what a person woudl be doing. My handrails are far enough apart where no one would touch both handrails at the same time.

This morning I tested water to rails and both were about 2.8 volts with the pool bonding wire hooked up to the new pool pump lug.

When I remove the bonding wire from the pool pump lug and it's not touching the pump at all (and isn't touching a ground rod either), I read 2.5 volts with one probe in the water and one probe touching the hand rail. (Meausing the other rail to the water got the same result).

When I put one probe in the water and one on the metal coping at the edge of the pool near the handrail, I got a measurement of 0.4 volts.

That's seems to be due to the the fluctuating neutral earth voltage from the house panel which powers the pump. Nearly everyone in the subdivision is probably home this morning running the HVAC, clothes washers, lights, etc. When I tested the same exact thing last evening around 7pm, I'm sure plenty of people weren't home on a Friday night and that's why I was getting about 4.5 volts in the same spot.

But I don't know why removing the bonding wire from the pump wouldn't bring the voltage measurement down to almost nothing if it was because of neutral earth voltage involving the house panel and pool pump.

But either way, it seems clear to me I have some bonding problems with the wire around the pool.

Except - and maybe this doesn't apply- there is a transformer box thing across the street in my neighbors yard (at the edge) totally surrounded now by shrubbery. It's directly across the street from my house. (underground electrical, no overhead lines) I read another post (you linked it) where there was a broken neutral wire to his house and when it was repaired, it fixed his pool issue. I'm wondering if there could be issue across the street that was putting some voltage in the ground that was causing an issue at the pool because of the water. (The electric company checked my house panel and say no issues but didn't look at anything else between my house and the transformer box across the street)

 

[mas985]

That's seems to be due to the the fluctuating neutral earth voltage from the house panel which powers the pump. Nearly everyone in the subdivision is probably home this morning running the HVAC, clothes washers, lights, etc. When I tested the same exact thing last evening around 7pm, I'm sure plenty of people weren't home on a Friday night and that's why I was getting about 4.5 volts in the same spot.

This is why NEV varies so much over the course of day. Not only that, but NEV can be caused upstream as well due to long transmission line phase imbalances. So it not always readily apparent where it is coming from.

But I don't know why removing the bonding wire from the pump wouldn't bring the voltage measurement down to almost nothing if it was because of neutral earth voltage involving the house panel and pool pump.

Do you mean the voltage at the pool? This is to be expected because the potential rise is due to the home neutral so disconnecting that from the pool area, would bring the bond wire back to earth potential (because it is touching the ground) instead of neutral potential.

But either way, it seems clear to me I have some bonding problems with the wire around the pool.

My thoughts as well.

Except - and maybe this doesn't apply- there is a transformer box thing across the street in my neighbors yard (at the edge) totally surrounded now by shrubbery. It's directly across the street from my house. (underground electrical, no overhead lines) I read another post (you linked it) where there was a broken neutral wire to his house and when it was repaired, it fixed his pool issue. I'm wondering if there could be issue across the street that was putting some voltage in the ground that was causing an issue at the pool because of the water. (The electric company checked my house panel and say no issues but didn't look at anything else between my house and the transformer box across the street)

Shorts to ground do not travel very far in terms of Earth Potential Rise (EPR). It depends on the length of the conductor touching the earth as well as it's diameter. So very short wires such as the example of a energized phone wire, drop in voltage to almost nothing in less than a foot.

Here is an analysis I did for a 48v phone line with a 1/2" of bare copper and the ground wire of the phone cable not connected back to ground (if it was, there would be much less current in the ground). Also, this assumes the power supply is perfect and has no internal resistance which is never the case in reality but shows a worst case.



Voltage drops as 1/R but the voltage gradient, the first derivative, drops as 1/R^2 and it is the gradient that causes shocks to occur because a voltage difference needs to happen between two points of contact. So where above curve is steep is the most likely location of a shock but the two locations have to be separated in space.

So unless there is a long rod introducing the voltage into the earth, the voltage dies off very quickly. The same would be true if the main power were somehow shorted to ground. The voltage is just 2.5x higher. But any cable that has a conductor showing is not likely to be very long so the voltage gradient dies off very quickly.

However, the point about the neutral have a bad connection back to the power company is a good one but unless I misunderstood you, you already said that was checked by the power company and the electrician. So that should be ok.

 

[Barry321]

However, the point about the neutral have a bad connection back to the power company is a good one but unless I misunderstood you, you already said that was checked by the power company and the electrician. So that should be ok.

The tech checked it closely. I wasn't sure what all he was doing but he poked around in the house panel for a good 5 mins - including tightening up some screws just to be sure (he said). He also pulled the meter and inserted what he called The Super Beast into the slots where he pulled off my meter. It looked like a test meter of some sort.

This is what The Super Beast apparatus says about itself "The Super Beast is a service conductor tester used to apply up to a 20 Amp artificial load on 120 volt service, to determine if there is a conductor, or neutral problem.

The Super Beast eliminates the need for homeowner to be present during testing. The utility employee can perform a test at the meter socket and immediately detect the source of the problem."

He said the test results were well within their specs and showed exactly what he expected it would show- which was normal for their purposes.

 

[Barry321]

This is why NEV varies so much over the course of day. Not only that, but NEV can be caused upstream as well due to long transmission line phase imbalances. So it not always readily apparent where it is coming from.

Yes. That's what the electric tech told me- that it would vary during the day some depending on the load in the area (subdivision, etc).

So let me see if I understand

1) The fact that some of the NEV is returning to the pool pump lug and then travels on the pool bond wire back around the pool would be normal? - or at least not unexpected in such a situation?

2) I would still want to keep the bond wire attached to the pool pump lug anyway, correct?

3) So the real issue issue would be the bond quality around the pool (handrails, etc) and even if the NEV is traveling back through the pool bond wire from the pump lug, proper bonding at the pool would eliminate any shocks because good bonding connections would mean a consistent voltage between pool components and the pool pump?

4) If #3 above is an affirmative answer, then what acceptable measurement around my pool in terms of voltage should I expect? Would/should it be near 0 or could it possibly be 5-7-10 volts (or whatever) but in that case it should be a consistent measurement around the entire pool if the bond is good?

 

[ajw22]

Voltage should be near zero between any two points that are bonded together.

 

[mas985]

The tech checked it closely. I wasn't sure what all he was doing but he poked around in the house panel for a good 5 mins - including tightening up some screws just to be sure (he said). He also pulled the meter and inserted what he called The Super Beast into the slots where he pulled off my meter. It looked like a test meter of some sort.

This is what The Super Beast apparatus says about itself "The Super Beast is a service conductor tester used to apply up to a 20 Amp artificial load on 120 volt service, to determine if there is a conductor, or neutral problem.

If he connected it at the meter, it may have only tested from the power co to the house but there could still be an issue from the meter to the breaker box or bad connection in the breaker box.

1) The fact that some of the NEV is returning to the pool pump lug and then travels on the pool bond wire back around the pool would be normal? - or at least not unexpected in such a situation?

What do you mean by return to the pool pump lug? The NEV is most likely due to a raised potential (relative to Earth ground) on the power companies neutral line. When you connect that neutral to the pump via the ground wire, since they are connected together in the breaker box, the pump now is elevated potential. When the bonding wire is connected to the pump, it becomes elevated potential as well as all the equipment attached to the bond wire. Remember, distant Earth (aka power substation) is the reference and considered 0v. Everything else is measured with respect to that voltage.

Ideally, the power cos neutral is 0v relative to the power substation neutral but if current is traveling along the neutral which it can under certain circumstances, and there is some resistance on the neutral, they tend to undersize them for cost reasons, then a voltage delta gets established along the neutral and the further you are from the substation, the worse it gets. The real issue is cost because they have to either increase the diameter of the neutral or attempt to redistribute power amongst the 3-phases so the neutral doesn't carry as much current. But again, this is only one cause of NEV but perhaps the most common.

2) I would still want to keep the bond wire attached to the pool pump lug anyway, correct?

If the bonding around the pool was proper, then yes, you want them connected. The issue is that connecting the bond to the pump raises the potential of the bond wire and attached equipment so when those items are touched in addition to something at ground potential (0v), a shock occurs.

3) So the real issue issue would be the bond quality around the pool (handrails, etc) and even if the NEV is traveling back through the pool bond wire from the pump lug, proper bonding at the pool would eliminate any shocks because good bonding connections would mean a consistent voltage between pool components and the pool pump?

Correct. If ALL the components are elevated to the same potential, it doesn't matter. This is why line workers can touch high voltage lines as long as everything is at the same potential or they are isolated sufficiently from ground.

4) If #3 above is an affirmative answer, then what acceptable measurement around my pool in terms of voltage should I expect? Would/should it be near 0 or could it possibly be 5-7-10 volts (or whatever) but in that case it should be a consistent measurement around the entire pool if the bond is good?

As close to 0v as possible. The lower the better and the less likely it will cause a shock.

In reality, voltage is symptom of the shock and not the direct cause. Current is the real culprit and that depends not only on the voltage difference between the two touch points but also, the resistance of those touch points to their respective voltage reference. Most of the time the resistance back the neutral is very low because of the copper wire but the resistance to earth ground is generally much higher since contact points are not infinite so that can determine how bad a shock is for a given voltage. So it isn't just about the voltage level.

If the issue is only the railings and those are at ground potential rather than bond potential, then you could just cut a slot in the concrete to lay a bond line to the railings. Is there an expansion joint already there that gets close to the railings?

 

[Barry321]

Left handrail- to water - 4.7 volts. (This is with the bond wire hooked to outer lug on pump)



Right handrail measurement 3.7 volts


Measurement at ladder rail- toward the far end of the pool - 0 volts


coping to water- this location is on the side of the pool between the handrails at the end of the pool and the ladder toward the other end - 0.67 volts.

 

[Barry321]

If the issue is only the railings and those are at ground potential rather than bond potential, then you could just cut a slot in the concrete to lay a bond line to the railings. Is there an expansion joint already there that gets close to the railings?

and run another bond wire back to the pump also?

 

[mas985]

and run another bond wire back to the pump also?

Or connect it to the existing bonding wire near the pool. Is that wire exposed anywhere near the pool? Sometimes they are only right below the deck along the edge but you do have to dig to find it.

Is it possible to get resistance measurements from each railing directly to the bonding wire (disconnected from the pump)? It may require a long wire to do that and a second pair of hands.

That will tell you for sure what is bonded and what is not. But I suspect the ladder is bonded but the other two railing are not or the bond is corroded. Have you removed the hand railings and looked at the anchors to see if they have any bond wires attached? They may just need some cleaning.

 

[Barry321]

When you connect that neutral to the pump via the ground wire, since they are connected together in the breaker box, the pump now is elevated potential. When the bonding wire is connected to the pump, it becomes elevated potential as well as all the equipment attached to the bond wire. Remember, distant Earth (aka power substation) is the reference and considered 0v. Everything else is measured with respect to that voltage.

ok.

But I am still measuring voltage even with the pool pump breakers off. Would the NEV travel back to the pump even with the breakers off? I assume it would unless possibly the ground wire or entire pump wiring was removed at the pump?

I should have measured the voltage at the handrails when they changed out my pump yesterday.

 

[mas985]

But I am still measuring voltage even with the pool pump breakers off. Would the NEV travel back to the pump even with the breakers off? I assume it would unless possibly the ground wire or entire pump wiring was removed at the pump?

Breakers do not disconnect neutral or ground wires. Those are always connected to the pump motor and where the NEV lies.

 

[ajw22]

. Would the NEV travel back to the pump even with the breakers off? I assume it would unless possibly the ground wire or entire pump wiring was removed at the pump?
.

A circuit breaker only disconnects the hot wire. Neutral and ground wires stay connected with CB tripped.

 

[Barry321]

Or connect it to the existing bonding wire near the pool. Is that wire exposed anywhere near the pool? Sometimes they are only right below the deck along the edge but you do have to dig to find it.

Is it possible to get resistance measurements from each railing directly to the bonding wire (disconnected from the pump)? It may require a long wire to do that and a second pair of hands.

That will tell you for sure what is bonded and what is not. But I suspect the ladder is bonded but the other two railing are not or the bond is corroded. Have you removed the hand railings and looked at the anchors to see if they have any bond wires attached? They may just need some cleaning.

1) I do see the bonding wire coming out from under the concrete pool deck. I know where that is. It's barely under the ground.

2) I am not sure I know exactly how to get the resistance measurement from each railing. I can ask my wife or son to help hold items. I do have a 50 foot long bare copper wire.

3) I tried to remove the hand rails but they are in there pretty good with the concrete. I assume I could chip those out with a large chisel and hammer (and safety glasses).

4) If they just needed cleaning, could corroded connections there effect the 0.6 volts I measured on the coping to the water on the side of the pool (About 6-8 feet away from the handrail?).

 

[JamesW]

Check the frequency of the voltage.

 

[mas985]

1) I do see the bonding wire coming out from under the concrete pool deck. I know where that is. It's barely under the ground.

2) I am not sure I know exactly how to get the resistance measurement from each railing. I can ask my wife or son to help hold items. I do have a 50 foot long bare copper wire.

So using an ohm meter, connect one lead to the exposed bond wire and connect the other lead to a railing. But again, do this with the bond wire removed from the motor.

3) I tried to remove the hand rails but they are in there pretty good with the concrete. I assume I could chip those out with a large chisel and hammer (and safety glasses).

Did you remove the top cover and there should be a bolt underneath that has to be loosened?

4) If they just needed cleaning, could corroded connections there effect the 0.6 volts I measured on the coping to the water on the side of the pool (About 6-8 feet away from the handrail?).

Probably not. But I would not be concerned about 0.6 volts unless you are getting a shock from that.

 

[Barry321]

Check the frequency of the voltage

Left


Right

 

[Barry321]

So using an ohm meter, connect one lead to the exposed bond wire and connect the other lead to a railing.

Did you remove the top cover and there should be a bolt underneath that has to be loosened?

1) So, can I wrap one end around the bottom of one of my handrails tight and run the wire over to near the existing bond wire as it comes out from under the concrete deck and test there?

2) I did loosen it and then tapped it pretty hard and the rails didn't budge. I think it has some concrete around it- enough to keep it in there pretty good. (This is something I did last summer. Haven't tried it this year).

 

[mas985]

1) So, can I wrap one end around the bottom of one of my handrails tight and run the wire over to near the existing bond wire as it comes out from under the concrete deck and test there?

Sure just make sure there is good contact.

2) I did loosen it and then tapped it pretty hard and the rails didn't budge. I think it has some concrete around it- enough to keep it in there pretty good. (This is something I did last summer. Haven't tried it this year).

It might just need a persuader.

 

[Barry321]

So using an ohm meter, connect one lead to the exposed bond wire and connect the other lead to a railing. But again, do this with the bond wire removed from the motor.

Just did this a few mins ago when I read your post. My wife held a bare cooper #8 wire end up against the handrail (i told her hold it against it steady and up against it tight) and I unwound the wire over to where the existing bond wire comes from out under the concrete deck- probably about 12-15 feet or so and put one probe against the wire coming from the handrail and the other up against the existing bond wire coming out from under the concrete pool deck.

0.016 on left handrail

0.049 on right handrail

This is with the bonding wire removed from pump motor