Pool Tingling when touching water and deck

[kp2654]

1. Pool electrical is fed from a secondary sub panel that is fed from another sub panel coming off the main service entrance panel.
2. I have verified that neutral is only bonded to ground at the main service panel. Neutral is not bonded to ground at any of the sub panels.
3. Folks have been feeling a tingle when stepping out of the pool. Here is what I have done to troubleshoot/identify the issue:
   1. Checked AC voltage between the water and the pool deck. Result was 6.2 VAC.
   2. Killed main breaker to house and measured again. Results were the same.
   3. Disconnected neutral in main service entrance panel with main breaker killed. Results were the same.

Any suggestions for further exploration?

 

[James]

Sounds like a fault either with an underground cable or the local sub station (transformer)

either way, this is a job for the utility company to investigate urgently

 

[littlespark]

We should just add that in the meantime, you shouldn’t use your pool.
Might be an opportune time to drain and clean it.

 

[Megawatt]

1. Pool electrical is fed from a secondary sub panel that is fed from another sub panel coming off the main service entrance panel.
2. I have verified that neutral is only bonded to ground at the main service panel. Neutral is not bonded to ground at any of the sub panels.
3. Folks have been feeling a tingle when stepping out of the pool. Here is what I have done to troubleshoot/identify the issue:
   1. Checked AC voltage between the water and the pool deck. Result was 6.2 VAC.
   2. Killed main breaker to house and measured again. Results were the same.
   3. Disconnected neutral in main service entrance panel with main breaker killed. Results were the same.

Any suggestions for further exploration?

My biggest question is your pool GFCI protected which should detect the leaking voltage. Yes all sub panels you are required to isolate the neutrals from the ground wires.

 

[James]

My biggest question is your pool GFCI protected which should detect the leaking voltage. Yes all sub panels you are required to isolate the neutrals from the ground wires.

This is still happening when main house isolator is off.
Fault must be an elevated voltage on the earth (edit: ground) cable or a local real earth potential problem.

 

[Mike57]

This is still happening when main house isolator is off.
Fault must be an elevated voltage on the earth (edit: ground) cable or a local real earth potential problem.

I had a couple of these shocking pool brain teasers when I worked at the electric company. I always enjoyed a new challenge. Customers called in pool ladder was shocking swimmers. Their pool guys said it was installed recently and grounded to code. The utility service reps couldn’t figure it out so they brought it in to engineering. Dumped it in my lap. Yeah! First I had our voltage tech who maintained our primary system equipment put a recording volt meter on the house meter. It breaks the voltage down to see an individual cycle. A $60,000 piece of equipment. Got some crazy chart readings off it. We were trying different things and killing the main breaker had no effect. It was seeing (if memory serves me) around 90 volts at only a few milliamperes. Kind of like wiping your feet on the carpet and touching someone’s ear. Now it gets interesting. Talking to the customer we found out that their shower drain was doing the same thing. House was built in the 80’s so we assumed pvc plumbing. We disconnected the neutral from the meter base on the house. The stainless pool ladder still had a voltage on it. We pulled the meter and 2 load wires out of the meter base. Still shocking. So we killed, parked and grounded the primary cable serving the pad mounted transformer. 19,900 volts single phase. Ladder still had voltage on it. Alright we called in the big guns, engineering standards group from corporate hq. We got with the cable and transformer manufacturers for input. I pulled the 30 old year old engineering prints where the system was first installed in the subdivision. Fortunately we still had the original paperwork.

Now I got something. The underground primary cable had an exposed concentric neutral. Wrapped outside the insulation. Secondly, it was direct buried, not in conduit. While the current standards are still direct bury, the cables are jacketed now, the concentric neutral is encased. And contrary to manufacturers recommendations, we put EVERY underground primary in pvc conduit. While it did lower the amp rating of the wire, it provided mechanical protection and facilitates easier replacement. So I drew up a Bad Order UG Primary replacement order to replace the entire URD (underground residential development) underground primary cable system. I did this around 2003-2004 and the cost was almost $100k. Lots of hand digging around other utilities in the easement.

The job was bid by contractors and was awarded to a company that had an old guy who put in the original system in the 80’s. He told me that there were numerous splices where the cable had faulted due to the exposed concentric neutral had corroded. Okay, that combined with the higher primary voltage at 19.9kv, typically it’s 7200 volts, made us suspect that may be where the induced voltage on the pool was coming from.

We replaced the entire system. From the overhead components on the riser poles, to cable, transformers, switch cubicles, even suspect service runs from the transformers to the houses, including the house with the pool. BIG job. Everyone was raising hell because we were digging up their yards and cutting concrete drives, which we patched. What was the end result? We never found out. As it turned out, the owners of the house with the problem were behind on mortgage payments and facing foreclosure. The house mysteriously burned to the ground.

Moral of this story is don’t always suspect the utility but it does have problems. Don’t think the evil electric company won’t do anything to try to remedy the problem and don’t complain about your electric bill. OGE is a regulated utility in Oklahoma and rate increases are rare. But you have to spend money to make money. Not only was the new system safer and more reliable, UG cable, equipment and even poles have about a 30 year life span. New technology and standards are light years more advanced. And there are thousands of miles of buried wire out there that has operated well past its life span. Your lights could go out any minute. Thanks for reading. Don’t fling to much doo doo at me. ;^)