Pool and Hot Tub

[APTCBR]

Hello,
I can feel a slight electrical shock when I am barefoot on my concrete patio and stick my hands in my hot tub. This happens even when the power is off and when the meter is pulled. The utility company has came out multiple times. I can read approximately 0.3 volts ac when I measure the voltage from the water to the concrete. The only thing that has made this go away is when they physically disconnected the neutral from my service and it comes back when they reconnect it. I have had two electricians verify that the hot tub is properly wired, grounded properly, etc.

Question #1: Can someone explain what this means?

The utility company is coming out to replace all of the underground to myself and my surrounding neighbors.

Question #2: Will this fix the problem that is happening?

I have never felt a shock in my above ground pool (standalone in the yard with the only connected electrical component being the pump when it is plugged it). The water in the pool also reads approximately 0.3 volts when measuring from the water to the ground. My pool is grounded and bonded and hooked up to a verified functional GFCI.

Questions #3: Is it normal to read that minimum amount of voltage in the pool water? Is it safe to use the pool with the proper grounding/bonding/GFCI if that amount of voltage (approx 0.5 volts) is present in the water?

 

[tom baker]

I will approve this as the poster is not doing work and ther is a shock hazard. The voltage you feel is from the utility and the linemen who come out don’t understand the issue. Your pool may not have the equalpotentional ground grid in the concrete or rebar ground as required by the code. Contact an electrical contractor with pool experience and do not use the pool.

 

[jim dungar]

Is this a built-in hot tub or a packaged spa type unit?

 

[APTCBR]

Packages spa type unit sitting on a concrete pad.

 

[AC\DC]

I forgot the phrasing but if it’s “ self contain” I believe you don’t need the equal potential ground grid.
I have never seen an above ground hotub that needs the ground grid.

 

[acrwc10]

I forgot the phrasing but if it’s “ self contain” I believe you don’t need the equal potential ground grid.
I have never seen an above ground hotub that needs the ground grid.

this isn't required for a self-contained spa but, this one obviously needs one.

 

[APTCBR]

I am getting confused…so equal potential grounding is not needed for this type of hot tub but due to the situation that is occurring I do need it. Can you provide some guidance on how I would achieve that for my hot tub (same as 680.26 for a pool?)

Also with my question regarding the pool, if I have never felt a shock or had an issue there, had my grounding and bonding checked, had my GFCI and wiring confirmed to be properly installed/functional, is is safe to be in my pool if my digital multimeter gives me a reading of 0.4 volts ac when I connect one probe in the pool water and one in the ground? Should that always be 0 or is it normal for some small trace amounts of voltage to be in the water?

 

[acrwc10]

I am getting confused…so equal potential grounding is not needed for this type of hot tub but due to the situation that is occurring I do need it. Can you provide some guidance on how I would achieve that for my hot tub (same as 680.26 for a pool?)

Also with my question regarding the pool, if I have never felt a shock or had an issue there, had my grounding and bonding checked, had my GFCI and wiring confirmed to be properly installed/functional, is is safe to be in my pool if my digital multimeter gives me a reading of 0.4 volts ac when I connect one probe in the pool water and one in the ground? Should that always be 0 or is it normal for some small trace amounts of voltage to be in the water?

This issue can be confusing because the problem is most likely not because of your system, yet the voltage is returning to the source via (partially) your neutral. Mike Holt videos on YouTube are really good at explaining what is happening. Look for the ones on "neutral earth voltage" and also swimming pools. From what you explain is happening, if you put in equipotential bonding as described in 680.26 and connect it to the bonding lugs inside the spa, especially the one on the heater, you will cure the problem. PS the GFCI is not the issue here.

 

[APTCBR]

Thanks for the response. I have watched his videos on NEV and from what I am understanding it is a normal thing to be there…would the equipotential grounding keep the NEV from reaching the water then where I would no longer be registering voltage from the water?

 

[retirede]

Thanks for the response. I have watched his videos on NEV and from what I am understanding it is a normal thing to be there…would the equipotential grounding keep the NEV from reaching the water then where I would no longer be registering voltage from the water?

The equipotential bonding is to keep everything that a person can touch while in the vicinity of to pool at the same voltage. That’s what makes it safe.

You might still measure some non-zero voltage between the bonded system and something else such as a rod driven into the earth some distance away.

 

[APTCBR]

Thank you. So if I have a vinyl liner with metal studs would it still be considered a non-conductive shell? If that is the case then I would not need 4 points and can just go with two points to two metal studs on opposite sides of the pool. I interpreting this properly for 680.26?

 

[APTCBR]

Another quick question. Hopefully my last. The provider replaced all of my surrounding underground but the voltage is still present in my pool and hot tub water.

Question: If the equipotential bonding of the pool is in accordance of 680.26 BUT I can still read 0.4 volts in the water, is it safe for me to be in the pool?

 

[acrwc10]

Another quick question. Hopefully my last. The provider replaced all of my surrounding underground but the voltage is still present in my pool and hot tub water.

Question: If the equipotential bonding of the pool is in accordance of 680.26 BUT I can still read 0.4 volts in the water, is it safe for me to be in the pool?

all metal parts and the water need to be bonded to the equipotential grid. the chemicals and minerals in the water will conduct electricity. That's why I suggested boning to the electric heater, it is in contact with the water and will bond it.

 

[APTCBR]

No electric heater on my pool. The pool is what I am referring to on my previous questions.

 

[retirede]

Another quick question. Hopefully my last. The provider replaced all of my surrounding underground but the voltage is still present in my pool and hot tub water.

Question: If the equipotential bonding of the pool is in accordance of 680.26 BUT I can still read 0.4 volts in the water, is it safe for me to be in the pool?

0.4V between what 2 points?

 

[APTCBR]

One lead in the skimmer water and one stuck in the ground.

I can also ready similar voltage with one lead on the metal pool panel that the skimmer is on and the other on the ground.

 

[retirede]

One lead in the skimmer water and one stuck in the ground.

I can also ready similar voltage with one lead on the metal pool panel that the skimmer is on and the other on the ground.

If someone in the pool can’t touch the “ground” you are measuring to, it should be fine.
Measuring between metal parts of the pool system (handrails, coping, lighting trim, pump, etc.) should always be zero volts.

 

[APTCBR]

What if the voltage reading in the pool water is 0.4 volts dc? Is that normal, possible phantom voltage?

 

[kwired]

My suggestion is to place something non conductive around the spa like maybe rubber mat or similar or at least in the area where you enter/exit the spa.

Eliminating the NEV is likely nearly impossible without replacing the concrete with an equipotential bonding grid installed in the new concrete. And that still doesn't eliminate the NEV it just equalizes touch potential in a limited area.

 

[APTCBR]

Thank you. I can give that a try.

With the pool situation - last question.

If I am getting 0 volts ac but 0.4 volts dc in the pool water, should I consider it safe?

Is it possible that the dc voltage reading is just because of the chemicals in the water are essentially making a large “battery” when the circuit is complete with one probe in the water and the other to ground?