*Shallow end, being shocked when grabbing railing*

[ParB]

I'm curious if there is any current present on the ground wire in the pool panel.

Even if you have a perfect bonding grid, you can still get voltage differences if current is flowing.

For example, if you have a 100 foot solid copper wire and you have 10 amps of current, there is a potential difference from one end of the wire to the other end of the wire.

Even though both ends are perfectly bonded, they have a difference in potential.

Theoretically, a bonding grid could eliminate all voltage or potential differences if the grid was perfectly isolated from the environment.

However, in the real world, the grid is connected to the earth and to the grounding system and if voltage is applied anywhere, current will flow and there will be differences in potential from one place to another.

The potential differences are based on factors like the amount of current flowing and the resistance or impedance of the conductive pathways.

I thought about this some more.

Just to be certain, there is not a bonding lug between earth and neutral in the sub panel causing an unbalanced load to travel through the sub panel and into earth via the pool handrail?

Is the sub panel from 2008 or newer and use 4 wires from the main panel?

Did you measure the current in your pool bonding wire or just the voltage?

 

[NowintersinAZ]

It was brought to my attention that IF there is poor grounding at the poles or boxes on lets say the cable tv coming to the house and voltage is being induced to the cable. Then if it's shield is connected to the Ground bar (as it should be) in the main disconnect. It could be carrying a small voltage on the EGC throughout the house and pool area. This would also account for lifting the EGC at the sub panel and the voltage disappearing. Just more to chew on.

EDIT: After thinking more on this I can blow holes in it. But it is worth a look and is not tough just pull the ground wire coming from the main panel to the block by the utility. You can then voltage test it there.

 

[Newdude]

Even less likely would be the water feed from the street, but it’s exactly the freak occurrence thing we are looking for. Anything that can conduct that is tied into the electric ground. Until they are ruled out at this point, anything that could carry stray current to the house is suspect

 

[gamerfan2004]

I would like to give all of you firm handshakes because I've really enjoyed reading all of this. I can fill in a few blanks on some questions that were asked:

• The meter panel and the home electrical panel are separated by plywood.
• I found that my water meter in the basement isn't bonded (how the did this happen? Late 1980's home)
• The pool was built in 2003, the bond runs from the pool pump. It was inspected and approved by the county.
• At that time, a sub panel was not required. We have a GFCI 30 A 2-pole breaker for the pump running out to a manual timer.

I will attempt to gather some more information over the weekend

 

[Newdude]

do you have an auto fill ?

 

[gamerfan2004]

do you have an auto fill ?

Auto fill?

 

[Newdude]

A sprinkler like line to the pool that fills it when it’s low with a boat bilge or toilet bulb water level sensor thingy

 

[Newdude]

Your water main not being bonded spurned some other thoughts. Before pex both Telco and CATV routinely grounded to the water spigot at the side of the house or the water meter in the basement if either was closer to their entry point than the electric panel, because the water pipe was ultimately grounded. Pex changed things because the homeowner could add plastic where there was copper and unintentionally break the bond. So for the last bunch of years they have been going to the electric meter or MGN.

If inductive voltage was entering through either the buried phone/TV wires which are thicker with sheaths, and grounded to a water line, the stray current could make it to the pool through an auto fill. You guys swim energized like a bird on the high voltage lines, until you touch the ladder.

Again, this is out there. But we are looking for a multiple failure that should not ever occur. Already stumping both an electrican and the power company, I’m really thinking it’s coming in another way that’s ultimately connected. Something like the TV/phone/water ground that’s realistically only there for a lightning strike or blown transformer is then carrying current to the pool.

Maybe this freak scenario jogs another thought in the collective brain trust. I’d rather be wrong 20 times if it helps somebody else zero in on what it is.

 

[NowintersinAZ]

Thank for the new info.

The meter panel and the home electrical panel are separated by plywood.

Are you comfortable turning off the main breaker in the panel and opening up the panel to access the neutral? (Most important make sure the main breaker is turn off before opening the panel!!) Don't not attempt if you are unsure or do not feel safe doing this. Call a licensed electrician.

If so turn off the main breaker open the panel (do not touch the lines coming in to the main breaker from the meter they are hot) and test for the voltage in the panel to make sure it's off and then at the pool.

If present at the pool and not in the panel, lift the neutral make sure it does not touch anything especially you and use a continuity tester and touch the box of the panel and the box of the meter (make sure to get through the paint) and see if you get a beep or zero ohms. If you get a beep or a ohms reading and not ol close everything up because they are bonded through screws or pipe and the test won't work.

IF you get OL they are isolated and now you can check the voltage at the pool.

If it was voltage was present when the main breaker was off and the neutral still hooked up, and then gone when you lifted the neutral it's riding in on the neutral.

If it's still present after lifting the neutral it's being generated inside the house or coming in another path walk around the house find the utilites and where they are bonded and remove the bonds one at time and test each time a bond is removed until all the bonds have been removed or until the voltage goes away. This will insure it's not coming from an outside source.

I found that my water meter in the basement isn't bonded (how the did this happen? Late 1980's home)

The bond is only for when the meter needs replacing, to keep the path complete. The meter will complete the path. Although I would add it asap.

At that time, a sub panel was not required. We have a GFCI 30 A 2-pole breaker for the pump running out to a manual timer.

Estimated length of runs? 50' 100' 1000' and size of wire IF the runs are long lets say over 250' because that makes a 500' run there and back and volt drop comes into play if the wire are not over sized for the circuit.

The temporary bond on the railing should be applied for safe reasons. It then can be removed under supervision while testing.

 

[markayash]

Thank for the new info.

Are you comfortable turning off the main breaker in the panel and opening up the panel to access the neutral? (Most important make sure the main breaker is turn off before opening the panel!!) Don't not attempt if you are unsure or do not feel safe doing this. Call a licensed electrician.

If so turn off the main breaker open the panel (do not touch the lines coming in to the main breaker from the meter they are hot) and test for the voltage in the panel to make sure it's off and then at the pool.

If present at the pool and not in the panel, lift the neutral make sure it does not touch anything especially you and use a continuity tester and touch the box of the panel and the box of the meter (make sure to get through the paint) and see if you get a beep or zero ohms. If you get a beep or a ohms reading and not ol close everything up because they are bonded through screws or pipe and the test won't work.

IF you get OL they are isolated and now you can check the voltage at the pool.

If it was voltage was present when the main breaker was off and the neutral still hooked up, and then gone when you lifted the neutral it's riding in on the neutral.

If it's still present after lifting the neutral it's being generated inside the house or coming in another path walk around the house find the utilites and where they are bonded and remove the bonds one at time and test each time a bond is removed until all the bonds have been removed or until the voltage goes away. This will insure it's not coming from an outside source.

The bond is only for when the meter needs replacing, to keep the path complete. The meter will complete the path. Although I would add it asap.

Estimated length of runs? 50' 100' 1000' and size of wire IF the runs are long lets say over 250' because that makes a 500' run there and back and volt drop comes into play if the wire are not over sized for the circuit.

The temporary bond on the railing should be applied for safe reasons. It then can be removed under supervision while testing.

Great idea!

 

[NowintersinAZ]

I wish I lived close I would love to go over and play.

 

[Newdude]

wish I lived close I would love to go over and play

My entire life is leading up to the moment that one day my kids will say the gnarliest of things :

‘My old man is a television repairman, he's got this ultimate set of tools. I can fix it.’

 

[gamerfan2004]

I wish I lived close I would love to go over and play.

I wish you did as well

I'll certainly see what I can do with all of these new suggestions.

 

[gamerfan2004]

A sprinkler like line to the pool that fills it when it’s low with a boat bilge or toilet bulb water level sensor thingy

This sounds amazing to have; no, I don't have one.

 

[ParB]

Thank for the new info.

Are you comfortable turning off the main breaker in the panel and opening up the panel to access the neutral? (Most important make sure the main breaker is turn off before opening the panel!!) Don't not attempt if you are unsure or do not feel safe doing this. Call a licensed electrician.

If so turn off the main breaker open the panel (do not touch the lines coming in to the main breaker from the meter they are hot) and test for the voltage in the panel to make sure it's off and then at the pool.

If present at the pool and not in the panel, lift the neutral make sure it does not touch anything especially you and use a continuity tester and touch the box of the panel and the box of the meter (make sure to get through the paint) and see if you get a beep or zero ohms. If you get a beep or a ohms reading and not ol close everything up because they are bonded through screws or pipe and the test won't work.

IF you get OL they are isolated and now you can check the voltage at the pool.

If it was voltage was present when the main breaker was off and the neutral still hooked up, and then gone when you lifted the neutral it's riding in on the neutral.

If it's still present after lifting the neutral it's being generated inside the house or coming in another path walk around the house find the utilites and where they are bonded and remove the bonds one at time and test each time a bond is removed until all the bonds have been removed or until the voltage goes away. This will insure it's not coming from an outside source.

The bond is only for when the meter needs replacing, to keep the path complete. The meter will complete the path. Although I would add it asap.

Estimated length of runs? 50' 100' 1000' and size of wire IF the runs are long lets say over 250' because that makes a 500' run there and back and volt drop comes into play if the wire are not over sized for the circuit.

The temporary bond on the railing should be applied for safe reasons. It then can be removed under supervision while testing.

This is a good idea. Try to figure out if this is a voltage carried on neutral or ground, or if it is an induced stray voltage. It could very well be something from a phone line or a cable company.

 

[JamesW]

It could very well be something from a phone line or a cable company.

That's why I would send them the oscilloscope readings to see if they can rule out their lines.

Maybe they use a different frequency.

Maybe they use DC or something where they could say that it couldn't be theirs based on the frequency.

Below shows an AC signal and a rectified AC signal to DC.

The signals might be rectified DC based on the sharpness of the points in two of the signals.

 

[Hadiguy05]

@gamerfan2004 I am very sorry to hear that you having problems with your pool. I've read through many of the posts and you've gotten a lot of amazing feedback and your methods of troubleshooting at AWESOME! There are soo many times where I still wish I had my oscilloscope from being in the field. It's a great tool. I hope that I do not re-ask many of the questions that have been asked already. Before we leave the pool and start looking elsewhere, let's focus there. The biggest concern I have is that the voltage potential in your bonding system is NOT the same (or at least I think so, from what I've read). That is a problem. The whole purpose of the bonding system is to ensure equipotential between all devices attached to that bonding grid. If there is no difference in potential you can't be shocked even if a voltage is present. We must have a difference in potential for a current to flow. If there is an bonding grid integrity issue, you will have a difference in potential in devices attached to the bond grid (assuming that the ground system is separate). What I can tell you from what I am seeing is that you have common mode voltage in your bonding system. I used to see this a lot in large industrial systems in my past. Pictures might help too.

1. Can you provide me a list of the equipment being used around the pool? Is the AC motor single speed, 2 speed or Variable speed?
2. Is each electrical device bonded? (not ground wire)
3. Is each electrical device grounded?
4. Is the bond grid isolated from ground or, are the two attached by a single wire or multiple wires?
5. Is the water bonded?
6. Had you had any equipment failures or changed anything out when you noticed this shock? (prior too)
7. Are you using any type of ground rods for the pool system?
8. The ground wire that goes from inside to outside is it a straight run (main panel to sub panel outside) or does it go through multiple panels?
9. Have the GFCI breakers been tested to ensure they function properly for the pool equipment?

 

[gamerfan2004]

I apologize for being away for a couple of days. We're getting new carpet in all of the bedrooms and about to receive my house load full of belongings that have been in storage. The joys of juggling life

@ParB @JamesW Added to the list
@NowintersinAZ I apologize, but the pool pump is running on a double pole 20 Amp breaker, not 30. The length of the line is maybe 100'.
@Hadiguy05 I honestly don't understand how the bonding failed on the anchors at the pool railing, it really doesn't make sense since it's encased in concrete.

I'll do my best to answer your questions, and I'll try to post pictures of the wiring as soon as I can.

1. Can you provide me a list of the equipment being used around the pool? Is the AC motor single speed, 2 speed or Variable speed?
Hayward Superpump 1.5HP single speed

2. Is each electrical device bonded? (not ground wire)
The bonding wire is attached to the pump and runs underground to the pool

3. Is each electrical device grounded?
Yes, the pool light and pump are grounded

4. Is the bond grid isolated from ground or, are the two attached by a single wire or multiple wires?
Would the ground going to the pump internally and having the bond attached externally on the pump qualify as attached? Would ground wires attached to the light switch connecting to the pool light qualify as attached?

5. Is the water bonded?
Yes

6. Had you had any equipment failures or changed anything out when you noticed this shock? (prior too)
No

7. Are you using any type of ground rods for the pool system?
No

8. The ground wire that goes from inside to outside is it a straight run (main panel to sub panel outside) or does it go through multiple panels?
Straight run out to the manual timer panel

9. Have the GFCI breakers been tested to ensure they function properly for the pool equipment?
Yes, all GFCI breakers have been tested

 

[JamesW]

In my opinion, the idea that there cannot be any voltage differences in a properly bonded system is flawed.

If current is flowing through the system, then you will definitely have voltage gradients.

Current is flowing through the entire property, so you can expect to have some gradients.

Without knowing the amount of current or every path it takes, it is impossible to know the expected gradients from one point to another.

 

[Hadiguy05]

In my opinion, the idea that there cannot be any voltage differences in a properly bonded system is flawed.

If current is flowing through the system, then you will definitely have voltage gradients.

Current is flowing through the entire property, so you can expect to have some gradients.

Without knowing the amount of current or every path it takes, it is impossible to know the expected gradients from one point to another.

@JamesW you will not have current flow at all without a difference in potential. The purpose of any equipotential bonding grid is to have all parts at the same potential. You are correct, there is a possibility for voltage gradients due to resistance in bonding cables, but this change in resistance should be so minimal that the current allowed to circulate is negligible, if the equipotential bonding system is designed correctly. If we don't have similar voltage at every point in the equipotential system, we either have a high resistance connection somewhere, or another unwanted path to ground (short circuit) so to speak. I used to design equipotential bonding grids for utility systems and work between lines on utility poles where we had equipotential bonding (to make a Faraday cage of sorts) to protect ourselves. Not that we should have to do this for a pool, but utility bonding grids have to be tested every 3 years to ensure that there isn't any changes in the resistance of the bonding grid which promoted unwanted voltage gradients. It was not uncommon for us to have to change out connectors for steel structures to bond wire, and in some instances rip up ground to expose the grid to fix something (i.e. loose copper split bolt which wasn't properly tightened during install).

I attached an article on purpose of equipotential bonding grids.

What is the purpose of equipotential bonding? | EEP

Equipotential bonding is essentially an electrical connection maintaining various exposed conductive parts at substantially the same potential.

electrical-engineering-portal.com