He told us the pool was shocking him

[kibb6961]

I have the same issue. Had people over last night and we thought the guy was crazy when he told us the pool was shocking him. Then I told my wife about it and she thought she was crazy when she felt it earlier in the year.

Went and got a multimeter today to start investigating and then it the web to find out information and here we are.

After reading the series of comments. Where do I start...

I have a 1.5-2volt differential from pool water to concrete slab. There is bonding around the permimeter and no mess in the concrete. Pretty much 0V differential when going from ladder to water (which makes since right?). Is it required that we have wire mesh in the concrete?

Tomorrow I will start checking connections for corrosion. (Figures I just finished the landscaping around the pool and the ground rod is buried under egg rock and landscape mat.)

 

[techguy]

Study pool bonding. If you have not bonded the water to the bonding circuit, this may be the place to start.

You can get a device that goes into your skimmer and I have seen some that are a PVC coupling with a copper conductor.

 

[danpik]

If you have a metal ladder then you already have a recognized water bond if the ladder is conected to the bond system. Concrete around a pool is considered a conductive surface and needs to be included in the bonding. You asked "Is it required that we have wire mesh in the concrete?". Around a pool, yes. Lately, with the advent of fiber reinforced cement, it seems that installers are forgoing wire reinforcement. This leads to the question of how to properly bond the concrete to the rest of the system. Two options here. First is to redo the concrete with rebar or wire mesh. The other is to have a concrete contractor come and saw cut a 1"-1.5" groove around the perimeter of the deck. Then install and grout in a stainless steel wire which then can be tied to the bond system. do not use a copper wire as copper and concrete do not play well together and in about 5 years the corrosion will isolate the copper and the problem will come back. another option, if the deck is not too wide is to have the sides of the slab drilled and have stainless rods inserted, grouted and then connected to the bond system.

 

[kibb6961]

The water should be bonded to the bond system. There is a pool light that is bonded and a metal ladder. I did some quick testing and the ladder, handrail, and water all appear to be at the same potential. The potential is from pool deck (concrete NO mesh) to the water. I am busy tonight but have a freind coming over to help take some measurements on Wednesday. We'll have better data then.

I believe there to be a bond loop (under the concrete of course) that connects the ladder, handrail, and diving board. The loop attaches to a ground rod. The niche light is bonded and potted and runs through conduit back to a lug terminal, the lug terminal has a wire conected to the ground rod. The pump has a ground wire running to the ground rod. Is this a proper bonding system?

Pool is 20x40 with 3 foot wide concrete on one side, other 3 sides have ~8-10 foot wide concrete. Is there a density of mesh or bar placement that can be used?

I have seen a pebble epoxy coating at a home show once (1/4-1/2" thick), is there a mesh I could attach to the bond system and epoxy coat the concrete surface?

 

[JohnT]

I believe there to be a bond loop (under the concrete of course) that connects the ladder, handrail, and diving board. The loop attaches to a ground rod. The niche light is bonded and potted and runs through conduit back to a lug terminal, the lug terminal has a wire conected to the ground rod. The pump has a ground wire running to the ground rod. Is this a proper bonding system?

The ground rod is not a good idea or needed in the US. You can connect the bond wire to the service ground at the panel, but it isn't required in the US. Connecting to a second ground rod can cause some ground current that could cause problems.

Your bond system is proper, but not complete. Wet concrete is a conductor, and as such needs to be bonded. Not easily done after installation though. If your pool has steel walls, they should also be part of the system.

It's important to recognize that in order to experience a shock, you have to have two problems.

The first problem is the incomplete bonding system. If the pool was fully bonded, you wouldn't feel the shock.

The second problem is the electrical source of the current. It's most likely a neutral to ground connection issue with your utility's transmission lines, although there are many other causes, including telephone wiring. Most of the time the source of the problem is inadequate grounding by the power company along the transmission path. As current flows through the neutral, a voltage drop occurs due to wiring resistance, but that same drop doesn't occur on the ground because no current flows through the ground lead. In rural areas where there are longer runs between service locations, the voltage can get high enough to cause the issue you are seeing.

 

[danpik]

I believe there to be a bond loop (under the concrete of course) that connects the ladder, handrail, and diving board. The loop attaches to a ground rod. The niche light is bonded and potted and runs through conduit back to a lug terminal, the lug terminal has a wire conected to the ground rod.

So far things are good. A ground rod is not required but is not a problem if connected properly. It is simply doing the same function as the perimiter wire burried around the pool (bringing the potential of the ground(dirt)) to the same as the water,ladder, etc.

The pump has a ground wire running to the ground rod. Is this a proper bonding system?

Can you elaborate more on this statement? Is the grounding system for the pump connected to this or is the bond lug of the pump connected to this. The pump must have a separate ground wire going back to the service equipment. Simply using a ground rod will not provide a proper short circuit path to trip an over current device. There should also be a bond wire connected from the bond lug on the pump to the bond system.(breaker)

Pool is 20x40 with 3 foot wide concrete on one side, other 3 sides have ~8-10 foot wide concrete. Is there a density of mesh or bar placement that can be used?

I have seen a pebble epoxy coating at a home show once (1/4-1/2" thick), is there a mesh I could attach to the bond system and epoxy coat the concrete surface?

Just thinking out loud here... I am wondering if the epoxy coating would insulate the pool deck effectivly taking it out of the picture.

Also, has it been particularly dry in your area this year? I am wondering if the dry earth/dirt/ground around the deck is isolating the current flow from the deck. In theory if the ground is wet enough the deck and attached dirt should even out potential gradients. Is this problem new, or is it something that has been around (your pool) for a while?. The reason I ask is in my area we had some rather wet summers a few years ago. Recently the last couple of years have been very dry and I ran across this same problem. A pool suddenly started shocking the kids where it never did in the past. Fortunatly the deck around th epool was small enough that tearing it up and puting a new one in with rebar was cost efective and solved the problem.