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Old 08-23-2011, 01:17 PM   #1
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Is being shocked in a properly bonded pool truly impossible or just improbable?


We have been installing pools for 15 years. We have the same electrician doing the bonding/grounding for most of that time. A pool that passed two electrical inspections last August, was properly bonded - steel wire under concrete, handrails, ladder, dive stand, slide legs, etc, bonded to steel pool walls using # 8 copper wire. Equipment properly bonded and grounded at our panel, which is tied into a panel in the customers garage, which I believe is tied into a panel in the house. This week the customers called stating that at a redent party, swimmers that touched handrail, ladder or coping/concrete (unlikely that they could touch the coping witout also contacting concrete) were getting shocked. My husband, admittedly an old "Pool Guy" went over yesterday and did not feel anything. he cleaned off the metal contacts in the ladder and handrail anchors and threw in a ground rod, hoping that will take care of the problem. From what I am reading about equipotential bonding, I suspect it won't. If I understand it correctly, in simplistic terms, grounding will prevent sending stray electrical currents from the pool and/or equipment into the pool/pool area. Any stray current, be it from the pool equipment, underground utilities, or a neighbors faulty electrical system, that enters an unbonded pool/pool area, has the potential to shock/electrocute people in the pool/ pool area. Proper bonding removes the potential. Is that correct? Is there any circumstance in which a pool could be properly bonded and people still get shocked? Like maybe in an unbonded pool they would have been electrocuted? The pool has a salt to chlorine generator. We would have added about 500 lbs of solar salt last year. Could that effect the requirements for grounding the water? The light ring is a non-corrosive molded plastic, but the niche is metal. The ladder is metal and protrudes into the water. Due to issues with salt pools where the ladder and handrails were permanently bonding to the anchors, we switched to bronze anchor and more recently plastic anchors with metal lugs/channel sets inside. If the bonding failed at some point, is there any way (other than removing concrete) to pinpoint where? If,so, can we just remove that spot from the grid? For instance, it it was at a handrail anchor, if we removed the ladder or put in a coated ladder (they make soe that are coated in the way a truck bed is coated)would that repair the bond? I apologize if these are stupid questions. I am trying to get my brain wrapped around all this bonding/grounding stuff and the old brain is not quite as pliable as it used to be. After two years of terrible economy followed by a season of non cooperative weather, I am trying to find an effective AND affordable way to eliminate any hazardous conditions.
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Old 08-23-2011, 11:15 PM   #2
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Is being shocked in a properly bonded pool truly impossible or just improbable?


It is essentially impossible to get shocked in a properly bonded pool, assuming the source of electricity is outside the equipotential bonding grid. That's what the equipotential grid is for. It creates a zone of safety that is completely protected from outside electrical conditions. If there is a source of electricity within the pool area, all bets are off. The source of electricity could be something faulty and improperly bonded in the pool system itself (like the pump or light), or it could be something much simpler: a "battery" accidentally created by having two different types of metal in the pool water at the same time. This is especially likely in a salt pool, where the water is highly conductive due to the dissolved salt. If you touch two dissimilar metals (like copper and stainless, or bronze and aluminum) at the same time while they are both in the water, you may feel a tiny tingle due to the electrolytic cell potential they generate. Salt-water boaters are familiar with this, from touching bronze and aluminum parts at the same time.

You mentioned you were having a problem with the ladder becoming stuck on the mounting anchors after changing to a salt pool. This sounds like an electrolytic corrosion problem, and may indicate that an accidental electrolytic cell exists that could be electrifying the ladder slightly. What is the ladder made out of, and what other metals are in contact with the water and also bonded?

Another issue though: you say the ladder anchors are now plastic. How is the ladder actually connected to the bonding grid?
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Old 08-23-2011, 11:59 PM   #3
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Is being shocked in a properly bonded pool truly impossible or just improbable?


Yes you can get a shock from or in a pool that is bonded.
If there is a current path thru the pool to ground.
If the current is not enough to blow a fuse/breaker
then it will continue.
Remember it doesnt take much current to hurt people
or paralise them only 100ma.
And this is a L O N G way from blowing a fuse.
Now even if there is a gfci,
and there is a current flowing at less then the trip point,lets say 20ma,
then the current will continue
Remember most people dont like any tingles,
No matter how small.
So YES you can get shocked from a bonded pool.

If the current is coming from electrolytic action between two
different metals, then you could try bonding them together.
Or changing one of the metals.

Last edited by dmxtothemax; 08-24-2011 at 12:06 AM.
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Old 08-24-2011, 12:21 AM   #4
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Is being shocked in a properly bonded pool truly impossible or just improbable?


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Originally Posted by dmxtothemax View Post
Yes you can get a shock from or in a pool that is bonded.
If there is a current path thru the pool to ground.
This is sort of true, but there is no way for a current path through the pool to exist if all the electrical equipment is properly bonded. If a current path through the pool exists, then there MUST be something improper about the bonding!

Quote:
If the current is coming from electrolytic action between two
different metals, then you could try bonding them together.
Or changing one of the metals.
They are ALREADY required to be bonded together. All metal things in the pool area must be bonded. If they aren't, then the pool is not properly bonded. This is why I asked about the plastic mounting for the ladder. My guess is that the ladder has no connection to the bonding grid, and there's some different metal in the water that people can touch at the same time.
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Old 08-24-2011, 12:46 AM   #5
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Is being shocked in a properly bonded pool truly impossible or just improbable?


I think the key point here is "party".....how do we know they didn't have something touching the water? Maybe a couple of colored lights?

Basically....if you drop a cord in water.....as people enter the water....the 'could' feel something....it won't be much....to get a real shock they would need to actually grap one of the electrical cord...

I would suspect that even with everything properly grounded...the paint on the pool acts as an insulator which would make it possible to have a voltage potential between the water and ground.

On a side note....if a person is in the pool and not touching anything....just floating in the water....you could drop a power line in the water and they would not be hurt.....that is until they try to climb out....
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Old 08-24-2011, 01:29 AM   #6
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Is being shocked in a properly bonded pool truly impossible or just improbable?


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On a side note....if a person is in the pool and not touching anything....just floating in the water....you could drop a power line in the water and they would not be hurt.....that is until they try to climb out....
This is absolutely not true. Water is not a very good conductor - people are as good or better. If there is current flowing through the water from a submerged conductor, any person in the water will carry some of that current. Whether there is enough current through the person to be dangerous depends on the current density in the water, in units of amps per square unit of area. The closer a person is to the source of the current, the higher the current density and the greater the shock.

Swimming in an electric field is especially dangerous because it can kill at much lower currents through the person than would be required to kill outside of water. It just takes enough to interfere with your muscle control a little bit, and then you can't swim. This is "electric shock drowning" and it's a serious problem around boat docks at marinas:

http://www.iaei.org/magazine/2007/07...hock-drowning/

This problem is greatly reduced in salt water, because the water is so much more conductive than a swimmer's body that the water itself acts like a three-dimensional equipotential bonding grid (Faraday cage), shunting the current around the swimmer. Anecdotal evidence suggests that electric shock drowning may not even be possible in salt water, although touching an electrified surface in salt water is still likely fatal. However, a salt-chlorinated pool is nowhere near as salty or conductive as ocean water so this is no help in a pool.
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Old 08-24-2011, 07:20 AM   #7
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Is being shocked in a properly bonded pool truly impossible or just improbable?


Is the water bonded?
http://waterbonder.com/

I believe this is included in the most current recommendations for pool bonding depending where you live.

This would seem to be more imperative since you've salt water system and the salt greatly improves conductivity of the water.
I also remember a thread where a neighbor's electrical system was somehow feeding back into the poster's system and causing issues with tingling. Might do a search of this board for that issue which was a long discussion.
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Old 08-24-2011, 08:21 AM   #8
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Is being shocked in a properly bonded pool truly impossible or just improbable?


There was an incident where I used to live of someone being shocked in their pool. Turned out it was because copper thieves had cut off the ground wire from a bunch of power poles.
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Old 08-24-2011, 08:39 AM   #9
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Is being shocked in a properly bonded pool truly impossible or just improbable?


This can occur in any pool, when ladder, handrails are removed nad reinstalled. If the pockets and euipment is not cleaned and tightened correctly when reinstalled.
I have seen it a number of times.
If a homeowner calls be about this issue, I check all equipment and than perform a bonding test to make sure evrything is still connected together.


"he cleaned off the metal contacts in the ladder and handrail anchors and threw in a ground rod, hoping that will take care of the problem."

Cleaning all the contacts is the good, but installing a ground rod is the wrong thing to doAs I sted above the elctrician should do a bonding test and remove the ground rod..
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Old 08-24-2011, 11:19 PM   #10
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Is being shocked in a properly bonded pool truly impossible or just improbable?


Within the pool itself there are stainless steel ladder and handrail. Light niche is stainless steel but I think there is some brass on it too. I know my children used to like to throw pennies into the pool and then find them. How much metal needs to be present? They have a Hayward Shark vacuum which has some metal components but probably wasn't in the pool at the time as the kids, but I will check. Since its bewen a year, they may have added some items. There are other metals that are in the ground, sperated by a vinyl liner. I think there is a volleyball net - I will have to ask someone about it. As to the ladders and handrails - There are anchors that go into the ground that ladders and handrails set into. These cups are bonded to the grid using lug nuts (I hope I am using all the correct terms - I am mainly an office person - the field person doesn't type or use computer and is presently snoozing). The cups come in aluminum, bronze or plastic. The plastic ones have metal inside them that rhe lug attaches to.) I have noticed in most of the cases of shocking that I have found while searching, the majority of the people writing do have salt systems. You cannot get any manufacturer to admit there may be a problem with them. During hot weather, could the currents that are generated to turn the salt to chlorine (I think its some type of current but not sure) actually create enough current to shock people? Is there any definitive way to test if the current is within the pool and whether it is annoying vs. dangerous, if there is any such thing. I have strong recollections of my dad having me stick my tongue out in order to test his 9v batteries. Unpleasant as heck, but hopefully no long term effects. As to the ground rods - I have seen contradicting information. The main theme seems to be that they aren't supposed to be necessary; however, might it be helpful and/or could it hurt? There are a lot of pools that were installed way before this eqipotential bonding came out. How would you make them safe(r) without digging everything up? On a final note - Is that Waterbonder thing for real or just a gimmick? I would be thrilled if that would solve the problem. Thanks for all the helpful input. I don't know electricity - but if any of you need spell checking, proof reading, recipe conversion, etc. - don't hesitate to ask

Last edited by LeighB; 08-24-2011 at 11:27 PM. Reason: after thought
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Old 08-24-2011, 11:33 PM   #11
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Is being shocked in a properly bonded pool truly impossible or just improbable?


The Hayward Shark is an electric device. It's pretty well designed to avoid creating a shock hazard, but it's not impossible. Would be good to figure out if it was in the pool at the time.

The salt chlorinator is very unlikely to be the source of the problem, but it's also not impossible. Are there bonded metal pipe sections between the chlorinator and the pool? It's not required but would prevent any problem with the chlorinator from resulting in current flow into the pool.

Has any testing been done to try to identify the problem? To figure out what the source of the problem is, you need to know that the voltage is real, what the voltage is, what points or surfaces the voltage appears between, whether it's AC or DC, and whether it's always present or appears only under certain conditions.
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Old 08-25-2011, 01:13 AM   #12
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Is being shocked in a properly bonded pool truly impossible or just improbable?


Quote:
Originally Posted by mpoulton View Post
This is absolutely not true. Water is not a very good conductor - people are as good or better. If there is current flowing through the water from a submerged conductor, any person in the water will carry some of that current. Whether there is enough current through the person to be dangerous depends on the current density in the water, in units of amps per square unit of area. The closer a person is to the source of the current, the higher the current density and the greater the shock.

Swimming in an electric field is especially dangerous because it can kill at much lower currents through the person than would be required to kill outside of water. It just takes enough to interfere with your muscle control a little bit, and then you can't swim. This is "electric shock drowning" and it's a serious problem around boat docks at marinas:

http://www.iaei.org/magazine/2007/07...hock-drowning/

This problem is greatly reduced in salt water, because the water is so much more conductive than a swimmer's body that the water itself acts like a three-dimensional equipotential bonding grid (Faraday cage), shunting the current around the swimmer. Anecdotal evidence suggests that electric shock drowning may not even be possible in salt water, although touching an electrified surface in salt water is still likely fatal. However, a salt-chlorinated pool is nowhere near as salty or conductive as ocean water so this is no help in a pool.
Your link is a bit lacking in details...

Bottom line....if the swimmer is not 'touching' anything else in the water, they will NOT be shocked. In order to be shocked, there has to be a voltage across their body. If they are in the water and the water is at a 1000 Vac....their body will also be at that same potential......but as long as they don't touch something...there there is no current flow...and no shock.

In the example you posted...I suspect they touched the boat or their feet touched the lake floor....

Case in point....have you ever seen the guys that work on high voltage lines? They use a helicoptor to drop them right on the line....do they get shocked? No. As they get close, they use a probe to get them and the chopper at the same potential...after that, they climb on.
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Old 08-25-2011, 05:46 AM   #13
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Is being shocked in a properly bonded pool truly impossible or just improbable?


I think I would use a voltmeter to test the voltage potential between the water and metal pool parts. Easiest might be between metal on the ladder and the water. Start with AC on the lowest voltage setting and put one lead's probe into the water and the other probe touching the metal part. Might try with pump on, off, and with circuit breaker on and off. An electrician should be able to help with the detective work.
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Old 08-25-2011, 07:05 AM   #14
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Is being shocked in a properly bonded pool truly impossible or just improbable?


You could check to see if voltage is present between the water and metal parts. Do a bond test as stated earler.

The Waterbonder is for real. I have installed tthem. It is an easy way to bond the water.

If all the connection for the ladder and handrails are tight and the bond does goes all the way back to the motor, heater etc, than the water is allready bonded by the ladder and handrail, providing they are metal.
If not metal than the water needs to be bonded.
The salt generators change 120 volts to 4-6 volts dc to run the generator. I have worked on many salt water pools and I have never had an issue of the salt generator causing a shock in the pool.

Last edited by NJMarine; 08-25-2011 at 07:17 AM.
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Old 08-25-2011, 07:06 AM   #15
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Is being shocked in a properly bonded pool truly impossible or just improbable?


You should get an electrician on the job as soon as possible.

As a pro your company is liable for all injuries from that installation.

Don't risk your retirement and savings to save a few bucks---

Think how this post will look in front of a jury.----Just a word of caution.---Mike---
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