*Shallow end, being shocked when grabbing railing*

JamesW

TFP Expert
Mar 2, 2011
25,709
This has to be an issue of bonding and stray current between bond and neutral. Something isn't bonded right in your pool and you are taking a stray current.

this may be of use: Stray current???
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.
 
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NowintersinAZ

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This has to be an issue of bonding and stray current between bond and neutral. Something isn't bonded right in your pool and you are taking a stray current.

this may be of use: Stray current???
Yes the fact that he is getting voltage readings from the railing to the concrete and also the water is a bonding issue.

The bond to the railing needs testing and or replacing which has been brought up in this thread before. What he is trying to do as I see it is find the source of the stray voltage that is between the neutral and the EGC and ultimately the bond around the pool since they are tied together.

Last I heard a temporary bond has not been placed on the railing or testing of the bonding grid.
 

JamesW

TFP Expert
Mar 2, 2011
25,709

The part where he drops a live wire in the pool is interesting because it shows that bonding does not make things safe.

It shows 10.35 amps of current flowing through the wire into the pool and then into the bonding grid and probably most of the current returns to the utility transformer secondary neutral through the equipment grounding conductor to the neutral bar in the house and then to the utility secondary neutral.

Even with bonding, the current flowing through the system is very high and the voltage gradients are also high.

Someone exiting the pool would be at highest risk touching a bonded handrail that was not touching the water because the human body would become the path between the water and the bonded handrail.

1626911234366.png
 
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ParB

Gold Supporter

The part where he drops a live wire in the pool is interesting because it shows that bonding does not make things safe.

It shows 10.35 amps of current flowing through the wire into the pool and then into the bonding grid and probably most of the current returns to the utility transformer secondary neutral through the equipment grounding conductor to the neutral bar in the house and then to the utility secondary neutral.

Even with bonding, the current flowing through the system is very high and the voltage gradients are also high.

Someone exiting the pool would be at highest risk touching a bonded handrail that was not touching the water because the human body would become the path between the water and the bonded handrail.

View attachment 357337
A good case for GFCI. Nice video, i like that guy.

My suspicion is that the stray current is introduced somewhere within the grounding system or far upstream. its worthwhile to turn off the main circuit breakers and measure voltage potential. I would not be surprised if it is still showing potential. It looks like its from a transformer rather than the shielding of lets say a phone wire, but i would get a skilled and experienced electrician to come a find the culprit.
 

NowintersinAZ

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Bonding in no way is meant to trip a breaker. It is meant to make an equipotential plane so that all items around the pool and in the pool are at the same potential. Throwing a live wire into a pool the water itself has to much resisence to allow it to trip a breaker unless it gets very close or touches a bonded object in the water.
 

ParB

Gold Supporter
wouldn't the GFCI detect that the current isn't returning on neutral if you throw a live wire in water and returns via a bond? eg. shouldn't that trip a GFCI? isn't the purpose of GFCI to detect current that isn't returning on the right path?

I don't mean the fuse, just the GFCI.
 

NowintersinAZ

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Oct 18, 2020
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A good case for GFCI. Nice video, i like that guy.

My suspicion is that the stray current is introduced somewhere within the grounding system or far upstream. its worthwhile to turn off the main circuit breakers and measure voltage potential. I would not be surprised if it is still showing potential. It looks like its from a transformer rather than the shielding of lets say a phone wire, but i would get a skilled and experienced electrician to come a find the culprit.
GFCI will only work in water if there is a bonded metal or a metal plate connected to ground that would cause an imbalance between the hot and neutral. That's why you are allowed to put a GFCI into a house with two prong receptacles and then down stream add three prong receptacles with our an equipment ground.
 

NowintersinAZ

Well-known member
Oct 18, 2020
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Mesa, AZ
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The part where he drops a live wire in the pool is interesting because it shows that bonding does not make things safe.

It shows 10.35 amps of current flowing through the wire into the pool and then into the bonding grid and probably most of the current returns to the utility transformer secondary neutral through the equipment grounding conductor to the neutral bar in the house and then to the utility secondary neutral.

Even with bonding, the current flowing through the system is very high and the voltage gradients are also high.

Someone exiting the pool would be at highest risk touching a bonded handrail that was not touching the water because the human body would become the path between the water and the bonded handrail.

View attachment 357337
Mike Holt is basically an electrical demigod. I do like his videos.
 

JamesW

TFP Expert
Mar 2, 2011
25,709
wouldn't the GFCI detect that the current isn't returning on neutral if you throw a live wire in water and returns via a bond? eg. shouldn't that trip a GFCI? isn't the purpose of GFCI to detect current that isn't returning on the right path?

I don't mean the fuse, just the GFCI.
Yes, a gfci would have tripped in the case of dropping a live wire in the water, but Mike specifically says that the wire was not on a gfci.
 
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NowintersinAZ

Well-known member
Oct 18, 2020
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Mesa, AZ
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Surface
Vinyl
Chlorine
Salt Water Generator
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Intex Krystal Clear
wouldn't the GFCI detect that the current isn't returning on neutral if you throw a live wire in water and returns via a bond? eg. shouldn't that trip a GFCI? isn't the purpose of GFCI to detect current that isn't returning on the right path?

I don't mean the fuse, just the GFCI.
Yes, but there are cases were a GFCI won't trip like in a hot tub with no metal parts in the water.
 

JamesW

TFP Expert
Mar 2, 2011
25,709
A GFCI will have 2 or three wires that go through a detector.

If the total current in both directions does not add up to zero, the GFCI should trip.

A GFCI basically works in a similar way to a clamp ammeter where if you clamp around all current carrying wires, they should cancel to zero as shown in the below video.


If all current going out does not equal all current coming back, the GFCI should trip.
 
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JamesW

TFP Expert
Mar 2, 2011
25,709
Basically two (Hot/hot or hot/neutral) or three (hot/hot/neutral) wires go through a toroidal transformer.

The current on both or all three should equal to zero in both directions.

If the current is not equal to zero in both directions, then a residual current is enough to activate a trip mechanism.

1626917065498.png
 

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