Stinging sensation – bonding issue, stray voltage, or something else?

[JamesW]

Maybe cut the rods down to 2 foot each and put them every 1 foot around the perimeter and connect them with bond wire?

50 rods would cost about $1,000.00 and would provide (200) 2' rods.

It's an expensive experiment that might not work, but a lot cheaper and easier than tearing out the deck and replacing it.

Only do it if approved by a qualified professional and on your own assessment of risks, costs and possible benefit.

 

[mas985]

The rod contact resistance is inversely proportional the surface area of conductor touching the soil. The longer the rod length, the lower the contact resistance and the further the rod voltage extends into the soil. The shorter the rod, the higher the contact resistance and the faster the voltage drops off with distance. This is why a 120v line that has jacket breach touching the soil really does not energize "dry" soil for much of an area around it. Maybe a few inches and that is it. Parallel rods do decrease the composite contact resistance by 1/N but again, the direction orthogonal to the line of rods will still drop off by the same amount. Substations use either a lot of rods and/or buried grids to get the contact resistance down to less than an ohm so that the substation neutral is pretty close to earth ground potential.

However, if you were able to drive the rods horizontal under the deck, that might work but very difficult to do. This would bring the conductor very close the bottom of the concrete lowering the resistance from the concrete to the bonding.

 

[JamesW]

However, if you were able to drive the rods horizontal under the deck, that might work but very difficult to do.

You would need to dig a trench perpendicular to the deck, slightly deeper than the deck and the length of the deck then just hammer the rods in.

So, a lot of work, but doable.

You can use a sledge hammer or a hammer-drill with an attachment.

Just be sure to stop before the rod penetrates through the wall of the pool.

Maybe additional water bonding would help.

 

[meie9635]

fascinating thread. I don't understand 90% of it, but pretty interesting.

 

[Bugman1401]

Not sure wasting $1000 for 2’ rods is a good choice or based on sound technical principles. If the top 5’ of soil is sand or dry clay, then any amount of 2’ rods does nothing. Most padmount transformers use 8 or 10 ft ground rods. Some utilities drive 30’ ground rods at the substation. I suspect the OP has his house connected to a xfmr that may have a ground rod that is in very sand soil or dry clay or had its ground connection come loose. I suspect his salty pool and bonding conductor maybe becoming a ground well for return neutral current for him and his immediate neighbors (off the same xfmr). I wonder if he would have the same issue if his pool was not SWG. I also wonder if OP has ever had the issue after a soaking rain when the shallow soil is more conductive.

 

[JamesW]

It’s definitely a risk based on an unproven hypothesis.

Maybe doing the horizontal and vertical rods would help, and maybe it wouldn’t.

It’s a huge cost for an uncertain benefit.

Many people have the same thing and they never figure out the exact cause and they never get a solution.

They just live with it and hope it’s not really dangerous.

The deck can be replaced and reinstalled with a copper bonding grid, which will likely help, but even that is not 100% guaranteed.