bonding vs grounding question

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Thank you sir. The ground rod was not there last year and we didn't have this problem but I'm thinking back on a thread where dloki mentioned the generator. I looked at my records and noticed that the generator was installed AFTER we closed the pool last year so I'm starting to wonder if something they did is causing a small amount of feedback even though it passed inspection for full installation.

I'm only getting a reading of about 0.2-0.4 VAC right now so you don't even feel it unless you have a cut on your hand. I just want to eliminate it completely.

If it were not eliminated completely, could this still be dangerous even if the bonding wire around the pool is okay?

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@danpik, it is insulated and in conduit.
 
Daggum it! I connected the grounding rod to the ground bar in the sub panel and re-tested. Still seeing a small VAC reading (between 0.2 - 0.4). Connected the bonding wire to the ground rod as well just for kicks and giggles. Still seeing a small VAC reading (between 0.2 - 0.4).

Anybody have any other suggestions short of having an electrician come out and figure out why there is voltage on the ground wire from the main panel when the hots are off and the neutrals disconnected?
 
cptserious said:
Daggum it! I connected the grounding rod to the ground bar in the sub panel and re-tested. Still seeing a small VAC reading (between 0.2 - 0.4). Connected the bonding wire to the ground rod as well just for kicks and giggles. Still seeing a small VAC reading (between 0.2 - 0.4).

Anybody have any other suggestions short of having an electrician come out and figure out why there is voltage on the ground wire from the main panel when the hots are off and the neutrals disconnected?
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You may need an electrician. Stray/transient voltage may be coming from somewhere off your property. You may want to contact your electrical utility, but it may be hard to find the right person to talk to as the customer service reps are probably not going ot have a clue what you are talking about. It is entirely possible it is a problem with a service feed, nearby transformer or other part of the utility network.
 
cptserious said:
Thank you everyone for the help! I am going to get an electrician out here again to look into this issue.

I have only one more general question.

If the bonding grid/wire is in tact, should it prevent something like this from happening?
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To understand bonding you need to understand "potential". I probably only understand it enough to be dangerous.....

Basically, bonding ties everything that can conduct electricity in/around the pool together. That way everything has the same potential to ground. When the items are properly bonded, there is no way you (your body) can become part of the electrical current path. If the pool water has stray voltage and the ladder is not bonded ot the water then when you grab the ladder you can become the path of the voltage from the water seeking a path back to the transformer. If they are both bonded together you are fine because all three of you (your body, the water and the ladder) are at the same potential.
 
Tim, You are about 99.9% correct on your explanation. The only thing not needed in it was the reference to ground. Grounding is one of the most mis-understood concepts in electricity. The easiest way to understand voltage potential, current flow is the simple electrical receptacle. On the hot side of the recept there is voltage potential but technically 0 volts. If you connect a resistive load between the hot and the grounded conductor (neutral) you will have current flow and measurable voltage of 120 volts (nominal) This is the same thing that is happening with voltage on a pool that the OP is experiencing. In the case of the pool we always think, or falsely assume, that the current flow is to the water. In some cases the pool. especially a salt water pool can be creating a voltage that is higher than the surrounding surfaces. A properly set up (0 ohms of resistance) bonding system will cancel out any voltage differences bu allowing the current to flow unimpeded and even out. The reason people feel it is they are a resistive conductor. In the case of the OP here there is something obviously wrong with the bonding grid around the pool. If there is a non resistive path connected to all items including the water there would be no voltage differential. It is possible, since the OP mentioned a high salt content, that there are different voltage gradients in the water. These may need to be evened out bu more than one water bond.

Dan
 

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Brianf60 said:
How does he make a 'water bond'?
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In many cases the reinforcing steel is utilized as the common bonding to effectively bond the water, but in other cases bonded metal ladders extended int the water, bonded metal parts of pumps or other metallic parts can be utilized. The code calls for 9 square inches of metal minimum.

If you do a search, there are all kinds of aftermarket water bonding products, like this one designed ot be installed in a skimmer: Amazon.com: POOL BONDING KIT
 
Okay so I did a little more testing and before I call out an electrician who may have no idea what to test (since he did install a ground rod and connected a #6 stranded cable to the neutral bus in the sub-panel and tied the bonding wire to it), I want to make sure I don't end up with another $250 troubleshooting bill with the same result which was the bonding wire/grid was bad.

When I disconnect the pool light and pump ground wires from the ground bar in the sub-panel, I no longer feel a shock. When I test the voltage of the ground wire at the sub-panel (which is directly run from the main panel in the garage), I get a 1.6V reading by putting the negative end into the ground and touching the positive end to the ground wire.

Could this be giving the different voltage gradients in the water that is causing the 0.2 VAC reading when going from the pool to the wet concrete even though the ladder is in the pool and connected to bond wire?
 
cptserious said:
Okay so I did a little more testing and before I call out an electrician who may have no idea what to test (since he did install a ground rod and connected a #6 stranded cable to the neutral bus in the sub-panel and tied the bonding wire to it), I want to make sure I don't end up with another $250 troubleshooting bill with the same result which was the bonding wire/grid was bad.
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Yeah, I'm not sure this guy really understands grounding and bonding

cptserious said:
When I disconnect the pool light and pump ground wires from the ground bar in the sub-panel, I no longer feel a shock. When I test the voltage of the ground wire at the sub-panel (which is directly run from the main panel in the garage), I get a 1.6V reading by putting the negative end into the ground and touching the positive end to the ground wire.
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When you do this, where are you probing the ground wire? At the ground bar in the sub panel and is it connected at the time to the system as it normally is? Is the ground bar in the sub panel bonded to the panel box properly and is the neutral isolated from it as well?

In fact, lets go back to the start of this and verify if the electrical system is proper. Assuming that your first point of disconnect is inside the house in the main panel, you should have 3 conductors entering the main panel two hots and a grounded conductor (often times referred to as a neutral) not to be confused with a grounding conductor. The Neutral, should be connected to a common bar that both the neutral and grounding conductors from your branch circuits connect to. This is the ONLY place in your entire electrical system where these are allowed to be on the same bar. In your sub panel, there should be 4 conductors (for a 240 volt system) entering the box. The two hots will connect to the hot bus either directly or thru a disconnect means. The ground wire should be on a bar that is connected (bonded) to the panel box. The Neutral is to be isolated, or floating in the box with no bonding at all to the ground system. Depending on the jurisdiction and the code cycle there may, or may not be a requirement for the box to have a ground rod attached.

cptserious said:
Could this be giving the different voltage gradients in the water that is causing the 0.2 VAC reading when going from the pool to the wet concrete even though the ladder is in the pool and connected to bond wire?
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I suspect that there is still a bonding issue here between the water and the area around the pool. Is this a concrete deck around the pool or is there grass or some other surface involved?

Dan
 
danpik said:
Yeah, I'm not sure this guy really understands grounding and bonding
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My concern too.

danpik said:
When you do this, where are you probing the ground wire? At the ground bar in the sub panel and is it connected at the time to the system as it normally is? Is the ground bar in the sub panel bonded to the panel box properly and is the neutral isolated from it as well?
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I'm probing the ground wire at the sub-panel directly to the ground wire coming from the main panel that is coming through the conduit. Yes, at the ground bar and on the ground wire itself (a little bit is showing) while it is connected normally. I believe it is bonded properly as it is connected with what appear to be two brass screws and the neutral bus is definitely isolated (completely nested in a plastic case).

danpik said:
In fact, lets go back to the start of this and verify if the electrical system is proper. Assuming that your first point of disconnect is inside the house in the main panel, you should have 3 conductors entering the main panel two hots and a grounded conductor (often times referred to as a neutral) not to be confused with a grounding conductor. The Neutral, should be connected to a common bar that both the neutral and grounding conductors from your branch circuits connect to. This is the ONLY place in your entire electrical system where these are allowed to be on the same bar. In your sub panel, there should be 4 conductors (for a 240 volt system) entering the box. The two hots will connect to the hot bus either directly or thru a disconnect means. The ground wire should be on a bar that is connected (bonded) to the panel box. The Neutral is to be isolated, or floating in the box with no bonding at all to the ground system. Depending on the jurisdiction and the code cycle there may, or may not be a requirement for the box to have a ground rod attached.
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All of this is as you say. The 2 hots connect directly to the host bus at the sub-panel. There is no ground rod attached but I do not know if there is a requirement for such. There is one now though because of the electrician but nothing is attached anymore.

danpik said:
I suspect that there is still a bonding issue here between the water and the area around the pool. Is this a concrete deck around the pool or is there grass or some other surface involved?
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My biggest fear is that the bonding grid/wire is corrupt because there is an approximately 4' wide concrete deck around the pool and ripping it out to check the bonding wire/grid only for it to still be in tact would be a nightmare not to mention expensive. The worst part about all of this is that I don't know how the pool was built and the companies that I believe installed it based on old paperwork I have from previous owners are no longer in business so I don't know if there is a rebar grid connected to a single bonding wire or if there is a full bonding grid. We did have additional concrete installed and they used rebar to ensure that when it settles, it doesn't tear away from the existing concrete but the closest to the pool wall is still 39" (45" to edge of old concrete minus 4"-6" for inserting the new rebar). I don't feel like the new contractors cut or nicked anything to do with the bonding wire/grid because they drilled into the side of the existing concrete and did not hit rebar which would lead me to believe that if there is a single bonding wire going around the pool then it would have been buried below the existing concrete and thus not vulnerable to cut inside the existing pool deck.

I guess I should say that this wasn't a problem last year BUT I had a generator installed and the old pump died on me so maybe I'm not connecting the pump correctly. I connected the two hot wires from the breakers to the L1 and L2 connections in the pump housing and connected the ground wire to the ground connection that sits on the electrical board. This is one thing I was curious about. There is also a second green screw with a the ground symbol on the motor housing. Which one should it be connected to and why would they have two in the housing of the Jandy pump (1 on the housing box and 1 on the electrical board next to L1 and L2)?

Sorry for the long winded information and thank you for taking time to review and comment!
 
Looking at the Jandy site and seeing the connection points for the motor It sounds like you are connected OK. The motor looks to be a standard pool pump frame with a speed controller attached (typical). The motor would, from the manufacturer, have a grounding point on it as well as the speed controller having the same type of connection. There should also be a bonding lug on the outside of the motor which may or may not have a grounding symbol on it. Is there a heavy bare copper wire coming from the ground in the area of the pump attached to it? I am suspecting, as are you, that there is no bonding grid in the concrete or it has been compromised. By the way you describe the voltage dropping after you cleaned the cups I am guessing the only bond to the concrete is the cups themselves. maybe someone you know with a metal detector could sweep over the deck and see if there is any metal in the concrete.

There are a couple of ways the lack of bonding have been repaired in the past without ripping the deck out. The one I am most familiar with is to have a 1" deep saw cut done to the concrete around the pool. A copper wire is then grouted into the saw cut and connections made to it via a saw cut to the edge. Another I read about was to have holes drilled into the edge of the concrete every 12" -18" radially around the pool and rebar sections grouted into the holes with connections to each. Another idea, floated out there a few years ago, was to have a wire mesh laid on top of the deck and a thin top coat of cement (1/8" - 1/4" thick) applied over that. Connections again made at the edge of the deck. I saw the first of these done about 7-8 years ago and it did eliminate the problem at that pool.

Dan
 
Yes sir. There is a #8 copper wire coming out at the equipment pad that is attached to the pump via the bonding lug. I even took some sand paper and cleaned up the wire so that they were both bright and shiny at the split bolt connection.

I've already got a call into a pool company to see what can be done but I'm hoping some of these options will come up.

Thank you sir.
 
What is the accuracy of the last paragraph in this article which is below? Pool Bonding 101: Why Handrails, Coping, and Water Could Shock You.

I feel like this could potentially be my problem since the ground wire coming from the main panel is feeding electricity back to the sub-panel when I don't think it should be.

[h=3]How Can we Eliminate the Problem?[/h] The first thing you need to do is contact your pool guy or a certified electrician to troubleshoot the problem. There is a chance the pool was improperly bonded if the pool was built before recent changes to the electrical code were enforced. The problem could also originate from your utility provider or from a wiring flaw outside of the pools bonding grid that is back-feeding electricity to the pool area. If the pool was bonded correctly there is a relatively good chance that the solution is simple once the problem is identified.
 
While it very well could be the "problem" you have identified at your property, previous issues reported have been traced to neighbors with faults in their system or problems with the electric utility.

I'll leave the details to Dan.
 
cptserious said:
Thank you Tim. I'm praying that it has to do with something other than the bonding wire. Fingers are crossed.
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I was interested to see Dan's "solutions". I really liked this one:
The one I am most familiar with is to have a 1" deep saw cut done to the concrete around the pool. A copper wire is then grouted into the saw cut and connections made to it via a saw cut to the edge.
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A guy who is good with a concrete saw could cut it in an hour or so and you could add the wire yourself.
 

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