Inground Pool Bonding Mystery

[Trickyrick33]

Looking for some advice on remedying a pool bonding issue. I’ve researched other threads but have had no such luck in identifying the problem. I’ve had a few electricians out and none have provided much help, all just want drive more ground rods. I live in a rural area and my options are limited. The power company has been out and says they’re not causing the leak.

Pool information - saltwater, 16x32 inground, concrete deck, steel walls, metal coping, pool light, propane heater, plastic steps and ladder with metal cups, metal basketball goal/frame, plastic slide with metal fasteners to the concrete, 110V automatic pool cover.

I’m currently getting 0.3 to 1 VAC from the coping to to the exterior bond loop. I can also get voltage from the bond loop to an installed ground rod as well as voltage from the water to a wet spot on the concrete deck. The original home owner had the bond loop tied into a ground rod at the pool sub panel as well as at the automatic cover. I’ve disconnected the bonding from the ground rods. I’ve tested for continuity from all items listed above. All had continuity to the exterior bond loop wire with exception to the slide and cover. I temporarily bonded these with a #8 with no changes to the problem. I am not sure if the deck has rebar or is bonded. Water is bonded and tied into the bond wire at the pump.

After checking for bonding I started to believe that my voltage leak was coming from within the bond loop. I’ve disconnected the neutral and grounds at the panel for all powered fixtures to the pool area and have no changes to the voltage.

Any ideas or words of wisdom to remedy this problem?

 

[LarryFine]

Welcome to the forum.

The voltage gradient may be coming from another source.

What do you have to turn off to make the voltage go away?

We're obligated to tell you to hire a qualified electrician.

 

[Trickyrick33]

I tried isolating each circuit to the pool individually by disconnecting all of the conductors at the panel but the voltage still remains. I haven’t been able to make it disappear even if I shut the power off at the main service panel breaker.

Power from the utility company comes overhead. No high voltage lines in my area. Nearest neighbor is a few acres away in a heavily wooded area.

 

[ptonsparky]

I tried isolating each circuit to the pool individually by disconnecting all of the conductors at the panel but the voltage still remains. I haven’t been able to make it disappear even if I shut the power off at the main service panel breaker.

Power from the utility company comes overhead. No high voltage lines in my area. Nearest neighbor is a few acres away in a heavily wooded area.

Your testing shows the source is not at your location. Do you share a transformer with the neighbor?
Source can be miles away.
You may need to check with your neighbors and see if they are having any issues

Again: Find a qualified electrician. (They may not be qualified if they want to add ground rods)

 

[rlundsrud]

Are you using a high impedance meter or a "low Z" meter? Is anyone actually getting shocked? Are there high voltage primary wires underground near the pool that feed the distribution transformer?

Inquiring minds want to know.....

 

[Trickyrick33]

I do not share a transformer with my neighbor.

I’ve struggled to find anyone competent with pool systems to work on it. I live in a rural area so there’s little in the way of permitting and inspections. I’ve had two of the most reputable residential electricians out and both are confused. Both have simply repeated everything I’ve done. I’ve also reached out several pool builders in the area and they’ve told me to just drive more ground rods. I had the power company out as well and they didn’t put much effort into investigating. They didn’t even go up in the bucket or even take the meter off. They said they would discuss it and call me back next week.

Short of demoing the concrete, I’m not sure which way to turn. Is it possible to be bonded correctly and still get a small amount of voltage in a saltwater pool? I originally suspected that the stray voltage was from a source inside the loop but I’m not sure now considering I shut the main breakers off and pulled the neutrals and grounds to everything at the pool but still show 1 volt from the water to the coping.

 

[ptonsparky]

High or low impedance meter is a need to know. What meter are you using?

Are you looking at AC or DC voltage?

 

[Trickyrick33]

I’m using a southwire 10030S meter. I assume it’s high impedance. I also tested with an analog meter and I’m seeing close to the same numbers.

The shock is real. My kids and wife can feel it, but I can’t even with cuts on my hands.

Strangely I can measure both AC and DC voltage. This afternoon the AC voltage was at 1.4 and DC was measuring .7 on the digital meter.

 

[Trickyrick33]

Are you using a high impedance meter or a "low Z" meter? Is anyone actually getting shocked? Are there high voltage primary wires underground near the pool that feed the distribution transformer?

Inquiring minds want to know.....

No high voltage lines underground.

 

[ptonsparky]

Cable tv, phone?

 

[Trickyrick33]

Cable tv from overhead. No phone. Old phone equipment still hangs on the house though next to the meter.

 

[ptonsparky]

Cable tv from overhead. No phone. Old phone equipment still hangs on the house though next to the meter.

Try disconnecting it.

 

[Trickyrick33]

Try disconnecting it.

I disconnected the cable tv line and removed the ground next to the meter. No change at the pool.

Old phone equipment is all cut inside the box. No lines feed into the box and the lines inside the box going into the house are air gapped. Nothing is connected.

 

[hillbilly1]

If the Voltage was a little higher, an Amprobe Pasar current tracer can trace it back to the source, but it really needs at least 9 volts ac or dc to trace. Do you have any solar panels? It would be unlikely, but might cause the dc voltage you are seeing. The teleco likes to run underground so they don’t have to lease poles from the poco. Is the main telephone lines buried? Or ran pole to pole with the power lines?

 

[Trickyrick33]

If the Voltage was a little higher, an Amprobe Pasar current tracer can trace it back to the source, but it really needs at least 9 volts ac or dc to trace. Do you have any solar panels? It would be unlikely, but might cause the dc voltage you are seeing. The teleco likes to run underground so they don’t have to lease poles from the poco. Is the main telephone lines buried? Or ran pole to pole with the power lines?

No solar. No underground telephone lines.

The neighbor has an underground dog fence that likely spans 7-8 acres around the perimeter his property. A good portion of the wiring is ran above ground attached to a wooden fence. I’m 2-3 acres away from the closest point of this fence. Otherwise there are no underground electrical feeds on my property with the exception of an aerator, outdoor wood boiler (which is on the opposite side of the away from the pool), and the pool sub panel.

 

[hillbilly1]

You say you had continuity between all parts and the ground loop, how low of continuity? In order to get the voltages between the parts you said, there has to be some resistance between the parts. If it was zero, the voltage cannot exist. You most likely have corroded connections. A megger will show these up.

 

[Trickyrick33]

You say you had continuity between all parts and the ground loop, how low of continuity? In order to get the voltages between the parts you said, there has to be some resistance between the parts. If it was zero, the voltage cannot exist. You most likely have corroded connections. A megger will show these up.

I didn't record the resistance at each object. I was just looking for a solid tone. In a couple days I’ll give it another go and record the actual ohm reading using an analog meter. How many ohms would be considered accepted?

 

[Fred B]

I didn't record the resistance at each object. I was just looking for a solid tone. In a couple days I’ll give it another go and record the actual ohm reading using an analog meter. How many ohms would be considered accepted?

How many feet of #8 would you expect between the 2 points of measurement? Then resistance of #8 a ratio of .06282 ohm/1000ft could be used.
But it should be simpler than OHM readings

Are your readings from bonded components and a remote point, or bonded point to bonded point? If all points of components are reading 1V to Remote earth point, That can be normal and the reason for pool bonding. If one point to remote earth is reading 0V and the rest are the 1V that would indicate that component is not bonded correctly. Moving your remote test point will "aim" you toward the source by observation of the lowest and highest differences (Ex: 1 spot has .5V another has .8V and 3rd has 1.2V and 4th point drops back down, the source would be "aimed" in that highest V direction.)
Simply if bonding is done properly there should be 0V difference between points of all the bonded components. If you have a difference you have a bonding issue, Usually not an easy fix, particularly if it is the pool surround.

Ground rods will do absolutely nothing to fix a bonding issue and may actually exacerbate the issue if voltage is from an exterior source such as a utility VD caused by distance from sub station or bad neutral (NEV) by creating a lower earth resistance for the components receiving the NEV.

Personally I would never connect the EP bonding to the panel grounding even though allowed but not mandated, as it can be a source for adding Voltage to the EP Bonding that might otherwise not be there.

 

[Trickyrick33]

How many feet of #8 would you expect between the 2 points of measurement? Then resistance of #8 a ratio of .06282 ohm/1000ft could be used.
But it should be simpler than OHM readings

Are your readings from bonded components and a remote point, or bonded point to bonded point? If all points of components are reading 1V to Remote earth point, That can be normal and the reason for pool bonding. If one point to remote earth is reading 0V and the rest are the 1V that would indicate that component is not bonded correctly. Moving your remote test point will "aim" you toward the source by observation of the lowest and highest differences (Ex: 1 spot has .5V another has .8V and 3rd has 1.2V and 4th point drops back down, the source would be "aimed" in that highest V direction.)
Simply if bonding is done properly there should be 0V difference between points of all the bonded components. If you have a difference you have a bonding issue, Usually not an easy fix, particularly if it is the pool surround.

Ground rods will do absolutely nothing to fix a bonding issue and may actually exacerbate the issue if voltage is from an exterior source such as a utility VD caused by distance from sub station or bad neutral (NEV) by creating a lower earth resistance for the components receiving the NEV.

Personally I would never connect the EP bonding to the panel grounding even though allowed but not mandated, as it can be a source for adding Voltage to the EP Bonding that might otherwise not be there.

I’ve attached a new section of #8 to the existing exposed exterior bond wire and measured from a metal component back to this line. This line is approximately 30 feet long. Ive also tested from the water to the coping and from the water to the concrete decking. The voltage readings have varied at different points using these methods.

Lastly, I’ve tested from the exterior bond wire to a ground rod that was originally driven for the sub panel just outside of the existing bond loop. I was seeing voltage doing this. I’ll test again to confirm that these are the readings I’m seeing. Most of my tests have been from the water to the coping and the readings do vary to a small degree at different points around the pool for this method.

 

[Trickyrick33]

I tested a few things tonight and found the
following conditions:

All readings with ground rod are to a ground rod outside of the bond loop. In some instances I attached the bond loop to it to see if it changed anything.


Water to ground rod outside of and not attached to bond loop - 0 VAC / 0 VDC
Water to ground rod attached to bond loop at sub panel - 0 VAC / .13VDC
Water to bond loop only - 0 VAC / .13VDC


Water to coping with bonding attached to ground rod at sub panel - 1.8 VAC and 1.03 VDC
Same result with bond wire removed from ground rod - 1.8 VAC and 1.03 VDC


Coping to bond loop - 0VAC / .98 VDC
Coping to ground rod outside of and not attached to bond loop - 0 VAC / 1.03 VDC
Coping to ground rod attached to bond loop at sub panel - 0 VAC / 1.03 VDC


All voltage from water to coping is highest at the closest point to the pool sub panel, pump, heater, and SWG. It is approximately half on the other end of the pool which has the automatic pool cover.



I drilled a hole to the steel edge of the pool shell and I'm seeing 300 ohms from this point to the bond loop about 8 feet away using a #8. The numbers just bounce around to approximately 1400 on the bare coping a couple inches away measured in the same fashion.

Seeing 800 ohms to this same point approximately 40 feet away on the coping adjacent to the pool equipment.
Seeing 200 ohms to the steel wall at the same location to the same point 40 feet away. Ohm readings were taken with a digital multimeter.