[TheJodester]

I have been living in my house with a 25,000 gallon inground vinyl pool for nearly six years. The pool also has an attached spa.

Yesterday, we noticed that when in the water at the steps in the shallow end and touching the concrete pavers right in front of the steps, we get a buzzing shock where we touch the concrete. Also, a "stinging" or "biting" sensation is felt on the body part where it meets the water surface (e.g. ankles). Also, if someone is sitting on the concrete, completely out of the pool, and someone in the pool touches that person, both people feel the buzz. Interestingly, no shock is felt when we touch the metal handrails on either side of the steps. The shocking by the steps is mild enough that quickly walking in and out of the pool does not cause you to feel it, but if standing stationary on the concrete and dipping your hand into the water and holding that position, it is enough to make you yelp. It's possible my husband noticed a very slight sting when in the pool and dipping his finger into the spa, which disappeared once he grasped the side of the spa with his other hand. He only felt the sting where he had a cut on his finger. This was a couple of months ago. No one else noticed anything significant until yesterday, and we even had a big pool party three days ago.

Today, I turned off the main breaker of the house and went out and tested it, and the shock still happens when I stand on the steps in the water and touch the concrete pavers. The intensity of the shock is rather localized to about a two- to threee-foot area in front of the steps. The farther you place your hands from this epicenter the weaker the buzzing gets. I tested this by the ladder at the deep end and various other random spots, and this is the only place I feel it. I also could not duplicate what my husband was talking about with the spa.

Some more info that might be relevant -- we live across the street from a high-tension-wire tower. Our soil is sandy/pebbly. Last summer, a transformer (I think) across the street exploded out of the blue, on a beautiful sunny day, and caused our power to flicker for a second and our next-door-neighbor's power to go out completely until LIPA (Long Island Power Authority) came to fix it. This explosion was in the front yard on the opposite side of the house from where I feel the shocks. The tower is on the same side of the house, however.

What puzzles me most is that no one seemed to notice this before this year, and I know people have sat on the concrete with their feet in the water many times. What could have changed?

Until this is corrected or diagnosed, is it safe to swim?

Thanks --
Jody

[tkrussell]

My advice is no, it is not safe to use until the issue is resolved.

More than 5 milliamps across the heart can be fatal.

Here is a previous thread that discusses a similar issue with shocks from pools:

https://www.askmehelpdesk.com/electr...ol-118962.html

I need to recommend that you have a qualified electrician come out and begin troubleshoot the problem, as this can be caused by so many reasons.

[KISS]

Not saying it's a fix, but it may be worthwhile doing until the real problem is solved. If you place a plastic tarp over the concrete that's giving you a problem, the shocks MAY go away since the tarp is an insulator, but it needs to be fixed.

Someone should get an idea of the magnitude of the voltage. Current kills when it flows through the heart muscle, stopping the heart. Only about 10 mA is necessary to do this and water lowers the resistance of the body.

I believe the soil has something to do with it and/or improper installation of the concrete. This is not what you wanted to hear, I'm sure.

You can read the section of the NEC code online for free that deals with pools by following the sticky in this section when you first posted.

What's supposed to happen is when the pool was installed, the concrete would have a metal grid embedded in it and the grid would be bonded together. This grid, the railing and the pool ground would be connected together so that they are at the same potential. This is usually electrically inspected before the concrete is poured.

Something is probably amis with this bonding structure. Your soil type contributes to the problem.

[Stratmando]

Do power poles feed you and your neighbors, including neighbors behind you?
If you can feel it, a Meter will show it and will be safer. If you MUST test with your hand, test with the backside, so any shock will pull your hand away instead of latching on.
An Electrician will start with what you did(turn main off) to determine if caused from a load from your house. Shorted pump. Landscape wiring, etc.
If it still shocks with house power off, I wonder if a neighbor has underground service going under your yard, and a rebar was driven into it. If an electrician can convince Electric coming from someonr else's service, they MAY be able to shut power off to nearby houses to determine the source.
I think I would shut power off to the house, and CAREFULLY remove Ground wire from Ground rod at pool equipment, to see if the voltage is present on Bond wire, or Ground rod. Ground rod and or wire may be live and can Kill.
Good Luck, Be Careful.

[TheJodester]

Okay -- the LIPA guys came. It appears that the problem is the trees, primarily those on the neighboring property, which they say are close enough to the high tension wires to conduct some electricity and send it through the roots of the tree. That would explain the shock as a recent development -- the root grew further onto our property. Plus, all the wet weather we had would make the trees especially saturated with water, making them more conductive. They tested voltage with a meter and when touching one tip to wet pavers and the other in the water, which is what we were experiencing, he got about 4 volts. However, when putting one tip between wet pavers and the other into the soil farther away from the pool and closer to our neighbor's property (and closer to the high tension wires) he got as much as 14 volts.

LIPA will send trimmers to cut back the trees. In the meantime, I am going out to Wal-Mart this afternoon to buy some sort of rubber mat to put on the ground in front of the steps. That way, no one will be touching the concrete and the water at the same time.

Does all this sound plausible to you guys? Oh, and how do volts translate to milliamps? (I'm pretty sure the readings he was giving me were in volts.)

[Stratmando]

The voltage read will be after being dropped by resistance and conductivity. Then the amount of current in amps/milliamps will be determined by the remaining voltage and your connection to ground.
Have him verify the voltage is gone when he is done.

[ballengerb1]

Not an electrician but I think it is foolish to try to continue using the pool until all is fixed. I have never heard of trees carrying voltage but maybe TK, Strat or KISS can tell us what they know.

[KISS]

Entirely possible:

Electrical energy applied over a distance is electrical field strength. Using an example of 20000 volts/6' (~2 m) is about 10,000 V/m.

Those lines could be 400 kV. Pointy things attract high voltage too. Not sure what the distance between the tree and the line is.

[TheJodester]

Entirely possible:

Electrical energy applied over a distance is electrical field strength. Using an example of 20000 volts/6' (~2 m) is about 10,000 V/m.

Those lines could be 400 kV. Pointy things attract high voltage too. Not sure what the distance between the tree and the line is.

There are a number of trees in pretty proximity with the line along the length of my property, but directly in front of where the shocks are felt there is an arborvitae (pointy) that looks about 4-5 feet from the wire.

The tree cutters are coming first thing in the morning. They actually showed up this afternoon, but it started to rain before they could begin. I want to have the voltage tested again after they trim to see if it made any difference.

Also, I was reading the other thread about this, and saw something about making sure that ground rods are below the water table to help reduce ground rod resistance when the earth's surface itself is creating the problem. Would this apply to trees, too -- that the farther the roots are from the water table, the more resistance they have? Where I live, the water table is about 50 feet down. Could this be contributing to the problem? A very deep water table, wet weather, pointy tree 4-5 feet from high tension wire?

[KISS]

Could this be contributing to the problem? A very deep water table, wet weather, pointy tree 4-5 feet from high tension wire?

One at a time:

The water table or close to it is likely the reference for the high tension lines. It may not be the reference for your
House.

Wet weather will make the tree more conductive. Have a lower resistance.

pointy tree 4-5 feet from high tension wire That's way to close.

Ask the guys what the voltage is of the high tension line is?

Lots of resistance (from HT line through tree and sandy soil to water table makes a large voltage drop. If you tie the concrete (via an embedded metal grid) to the railing and also tie it to the water (skimmer plate, for instance), then the water, railing and cement are at the same potential.

Following the NEC guidelines for pool installations should make this a non-issue. I'll still be that the concrete isn't bonded. 4-5 feet is way to close to the tree, but knowing the voltage on the lines would help.

This is probably clear as mud: Bonding of Pool Water [Archive] - Mike Holt's Forum

Bonding of the pool water: bonding of pool water [Archive] - Mike Holt's Forum

[TheJodester]

The guys didn't seem to know off the top of their heads what the voltage of the line is. I think he said something like, "It could be 40,000 volts, it could be 400,000." I doubt the tree trimmers will know either, but I'll ask anyway. When the power company guy retests the voltage of my yard, I'll ask for a definite number.

Just trying to be sure of something -- we have concrete pavers (i.e. bricks) for the pool surround, not poured concrete. Does that matter? Would there still have been an equipotential grid beneath them? I assume the only way to know for sure is to rip up the pavers, right? Or is there some kind of instrumentation to determine the presence of such a grid?

[KISS]

I don't know, but I suspect not. A simple metal detector that utilities use would determine the presence of something metallic.


FWIW: There is sophisticated instumentation called ground penetrating radar that's used, for example to locate artifacts, graves, plumbing and leaks under a slab or anything that changes the density of the soil. See Ground-penetrating radar - Wikipedia, the free encyclopedia

Welcome to Virginia/Maryland Ground Penetrating Radar Systems

[tkrussell]

As I said in my first post, hire a qualified electrician to troubleshoot this issue.

If you have any questions about grounding have the electrician determine this.

Do not attempt to investigate what your grounding system is now, as there is much you do not know about grounding.

Do not attempt to begin to understand grounding, and what may need to be done to correct any deficiencies.

Also, as you are aware now, do not ask tree cutters about the utility electrical system.

Only deal with the Power company representative.

Be sure to put the power company on notice that you need this resolved, and must know exactly what caused this and what the solution is.

They may try to ignore you, or give you limited information.

Keep in mind, they know that they are liable for any damages or possible injury that may be caused by their negligence.

[TheJodester]

Okay -- some more info. The high tension wires are running at 69,000 volts.

I now have a cut on my finger from slicing bread yesterday, and I feel slight shocks on the cut all around the pool if I touch wet pavers with one hand and stick the cut finger into the pool. I do not feel anything if I put a non-cut body part into the water except by the pool steps. I also feel the shock on just my cut when I put one hand into the water and the other into the spa. This is what my husband experienced a couple of months ago when standing in the pool, and he said the sting stopped when he grasped the plastic edge of the spa with his other hand. This makes me wonder: Is it possible that the water of the pool is somehow receiving current from the nearby tension wires through the air?

Spoke to the pool company. The pool was installed several years before we bought the house, but the owner is pretty sure that there is no equipotential grid under the paver patio. He said their procedure is as follows: It's a steel pool with grounding wire run around it and an electrical inspection done on the whole system before the patio is put in.

[KISS]

Typically you'll find distribution voltages of 15 or 4 KV in a residential neighborhood. This is a BIG difference from 69 KV.

See Electricity distribution - Wikipedia, the free encyclopedia

The setup that you have, I think would be more susceptable to shock because of the higher voltages. Somebody missed the detail here. I don't think it was intentional and I don't thnk there are any guidelines for installing pools near 69 KV type of voltages.

How close if your nearest neighbor? Specifically the nearest neighbor's water line. Is it in the path of the pool from your electrical service?

[tkrussell]

Why I said to get someone to check this. 69KV is a big deal, this is extremely strong lethal energy. If the trees were just touching, the tree will be vaporized or caught on fire. If contact was good the high voltage protection would kick in, or off as it were.

I was a half bock away from a 69KV line falling and hitting the ground, I saw the flash. The sound was deafening, and the ground was in bad shape.

This is killer stuff.

If contact was just right, and neither happened, then something would be steaming, or some indication other than the tingle.

Good question, can it go through air. There is an event called corona, this is where the sharp points come in, the air becomes ionized between a live surface and a pointed grounded object. This usually occurs at sharp points on insulators.

This is not typical of trees and HV lines. Believe me, there are plenty of trees in Maine that are extremely close to HV lines. Everyone has a generator here.

You mention a transformer blowing, is this ground mounted, or are there any underground lines. These are susceptible to all kinds of weird things, and go undetected.

Hate to sound like a broken record, but by hiring someone with good test equipment. BTW, we use ultrasound detectors to find corona, not your typical electrician will have this.

But a good service electrician will be able to check all local wiring including the grounding of the entire system. Be sure to ask for that specialty.

Bad system grounds at services have been known to leak or connect power from the grid into homes. Shutting off the Main was a good start, but does not end there.

Once a licensed electrician disqualifies your system from any fault, then he can push the utility to look into this further. If they are, or any reason for that matter, the cause, it will not get better or or go away on its own.

Could be any hand rail or metal piece of the pool was not grounded properly, or the connection has failed. An electrician should know that temp grounding a surface to a know ground will help determine this.

Pavers do not use reinforcing steel, as in poured concrete. The steel mesh is intentionally grounded. All metal within five feet of the pool is bonded to this grid.
The grid is then connected to equipment ground by a #8 wire, this is true for your system also, to a lug on the exterior of the pump motor. The equipment ground of the feed to the pump motor then gets grounded back at the breaker panel..

As you can see there is a great deal to check.

You can try chasing the utility, but I just don't think you will get far, unless they can see something fairly obvious. I do suspect any underground utilities nearby, and grounding problems.

[TheJodester]

The 69,000 volt wires are transmission lines running directly to the power station. They are live wires that cause the tops of trees near them to turn brown. A bit further away on the neighbor's property are distribution lines with the thicker, black-coated wires. Those are 14,000 volt lines.

How would I determine where the neighbor's water line is?

The tree cutting foreman suggested that I call LIPA again and have someone a step up from a regular service person come and diagnose to rule out (or confirm) "voltage tracking." P.S. -- after them trimming trees all day, there are still shocks in the pool. No trees are in contact with any of the transmission lines anywhere now.

Everyone I talk to seems mystified that we still feel the shock even when the main circuit breaker for our entire property (including pool pump and lights) is turned off. This leads me to think it HAS to do with the LIPA lines. What do you think?

[KISS]

Here is an interesting article concerning pavers and pools:

http://www.rctlma.org/building/conte...s_and_spas.pdf

[TheJodester]

Sorry, TK, I was just answering KISS when I saw your post.

The transformer that blew was mounted on a wood telephone pole. I don't think there are any underground lines here -- it's an older neighborhood (most houses built in the late '60s, before they buried telephone and electric lines around here).

I agree with your sense that I won't get much farther with the utility (LIPA). But I'll keep pushing. So, you're saying that the fact that I still felt it with the Main off does indicate some problem with the utility on some level?

[tkrussell]

No problem, I saw the time stamp.

To answer your last question, Not necessarily, I was referring to if there were underground lines, but there have been instances where house wiring had problems because of grounding problems in your home and/or outside, even on utility poles. Look at utility poles, and any wire you see running down to the ground from above that is broken or damaged is an obvious reason.

Other homes or utilities connection problems can be sending you stray voltages on your grounding system. Defects in your system exasperate this condition.

Utility systems, esp 69 KV levels, usually are well installed and maintained. Not to discount them, but utilities usually know the consequences of high voltage.

Home wiring and overhead utility systems are more prone to bad installations (homes), and wear and tear, both homes and utilities.