A slight "shock"

Jump to latest Follow Reply
If you had a grid of superconductive wires that was isolated from the rest of the world, you could have a perfect bonding grid.

However, the real world is much more complicated. If you have a voltage source and a destination that is at a different potential, you will have current flow.

Any time that you have current flow and any resistance, you will generate a voltage differential

So, if you have an underground wire leaking electricity, and it gets to something on the bonding grid, current is going to flow through the grid to wherever the voltage is different.

There can be multiple connections between the ground and the bonding grid. Such as at the pump, light niche etc.

Because everything on the bonding grid has different conductivity, you will have some voltage gradients.

You have water, concrete, copper, steel etc.

So, you will never have a perfect bonding grid with zero potential difference between different points when you have a voltage source and a destination that supports current flow.

The grid should reduce the voltage differential to a safe level assuming the grid is in good condition and the current flow is not too high.

So, you can get noticable nuisance voltage, but hopefully, it won't be dangerous.

Note: When you have a wire powering a load, you get a voltage drop. So, the voltage at the breaker might be exactly 240 volts, but the voltage at the pump will be lower, maybe 235 volts.

The voltage drop depends on the current (amps) and the resistance (impedance) of the wiring. So, even though the two points are connected by copper wire, they are not at the same voltage. If the pump is off (zero amps) there is no voltage differential.
 
Last edited:
Ok, so I have had people chasing this bonding grid issue for years thinking it was bad when in reality, it is highly possible the grid is fine and that if I find the source of the stray voltage that will resolve the problem?? And if that is the case, the trench I just had cut that cost me 650.00 was really for nothing...
 
wow man i feel for ya. I will hold by the fact that if the connections are not welded ( as in the re bar ) or soldered as in other connections then a bad connection will result. A mechanical tight fit connection does not mean an electrical correct connection. But in most cases we can "get by" by doing a "that's close enough, leave it " ... The wire ties on rebar for most is to keep them in line until the cement is poured and those doing this has no idea what a Bond is.
The surface water on a cement pad is going to be very hard to bond.
Not being on site and doing the test myself i will say this in a careful manor, "don't try this at home " lol,, but i would say based on what you are saying now that all is good and what you get is normal. That low a voltage at your pool and the neighbors should be livable. BUT as i said i am saying this based on your test and what you saying. Not sure if i mentioned this to you on here before or elsewhere but your best bet is a marine electrician. They are up to date on this as it is very common to have strays in marinas due to some crazy wiring practices on the boats and in the wiring feeding the dock lights and the outlets for plug in's. There are special probes for the meters that go in the water and that is what the proper guy for this job will have.
 
1Sammy said:
wow man i feel for ya. I will hold by the fact that if the connections are not welded ( as in the re bar ) or soldered as in other connections then a bad connection will result. A mechanical tight fit connection does not mean an electrical correct connection. But in most cases we can "get by" by doing a "that's close enough, leave it " ... The wire ties on rebar for most is to keep them in line until the cement is poured and those doing this has no idea what a Bond is.
The surface water on a cement pad is going to be very hard to bond.
Not being on site and doing the test myself i will say this in a careful manor, "don't try this at home " lol,, but i would say based on what you are saying now that all is good and what you get is normal. That low a voltage at your pool and the neighbors should be livable. BUT as i said i am saying this based on your test and what you saying. Not sure if i mentioned this to you on here before or elsewhere but your best bet is a marine electrician. They are up to date on this as it is very common to have strays in marinas due to some crazy wiring practices on the boats and in the wiring feeding the dock lights and the outlets for plug in's. There are special probes for the meters that go in the water and that is what the proper guy for this job will have.
Click to expand...

Thanks. It could be "liveable" if it weren't for my 4 year old feeling it worse than us and being scared of the water. So now I am on a mission to find the stray voltage source. I am getting an inspection consultation which will get the local inspector out to work on it until resolved.

Great idea about the marine electricians! If you brought that up before, I missed it. I'll look for one in my area.
 
Part of the problem is that we don't know if you have a bad grid or a strong source producing a current flow through the grid or some combination of both.

You have to check both until you can solve the problem.

A marine electrician is a good idea. They chase down stray current periodically. Maybe go to a marina and ask them to refer a good master electrician.
 
JamesW said:
Part of the problem is that we don't know if you have a bad grid or a strong source producing a current flow through the grid or some combination of both.

You have to check both until you can solve the problem.

A marine electrician is a good idea. They chase down stray current periodically. Maybe go to a marina and ask them to refer a good master electrician.
Click to expand...

Exactly and the more I am learning about this, the more I see the fact that both aspects should have been looked into at the same time rather than separating the issues. That is my fault. But I am learning here. I'll update after I work with the inspector and my buddy at the power company.
 
Try the tests that I suggested to see what that shows.

Separate the bonding grid from the ground rod and test voltage, current and frequency on ac and voltage and current on dc. Put one lead of the multimeter on the bond wire and the other lead on the ground rod.
 
JamesW said:
Try the tests that I suggested to see what that shows.

Separate the bonding grid from the ground rod and test voltage, current and frequency on ac and voltage and current on dc. Put one lead of the multimeter on the bond wire and the other lead on the ground rod.
Click to expand...

That's the plan tonight when I get home. One other question, I removed the bond wire from the ground rod, but it still runs to the ground bar within the sub panel. Is that okay, or should that be unhooked from the grid as well?
 
Bond wire should not be connected to the subpanel or any ground. The bonding grid and all things connected to it is supposed to float at its own potential independent of the ground.

The theory is that if all things connected to the bonding grid are at the same potential then you cannot get shocked.

You can try different connections for testing purposes but then I would disconnect it.
 

Enjoying this content?

Support TFP with a donation.

Give Support
The bond wire and the ground wire are going to be connected in multiple places. The ground wire for the pump and the bond wire are connected to the same metal frame. The bond wire outside the light niche is directly connected to the ground wire. The bond wire and the ground wire are connected to the same metal frame of the subpanel. They're connected.
 
JamesW said:
The bond wire and the ground wire are going to be connected in multiple places. The ground wire for the pump and the bond wire are connected to the same metal frame. The bond wire outside the light niche is directly connected to the ground wire. The bond wire and the ground wire are connected to the same metal frame of the subpanel. They're connected.
Click to expand...

The less you have bonds and grounds connected together the less points you have the possibility of differing potentials on the bonding grid.

This stuff is not perfect because of differing resistance at different points in the bonding grid.

Nuff said.
 
ajw22 said:
The less you have bonds and grounds connected together the less points you have the possibility of differing potentials on the bonding grid.

"This stuff is not perfect because of differing resistance at different points in the bonding grid."

Nuff said.
Click to expand...
And that is why everything should be welded or soldered. Then ALL will be on the same potential and a shock would be impossible.
 
These are the debates and differing opinions that are described in the article in post #134.
 
TN94z said:
I don't see what in the article would justify saying the inspector was wrong??? Maybe I missed it
Click to expand...

That wasn't specifically what I was referring to. More the overall different opinions here on what should be done. These debates go on among the industry experts.

I can guess what @JohnT may be referring to but he needs to be more specific. Debating it is not going to fix your problem. Finding the source of the electricty in the ground in your area will.
 
ajw22 said:
That wasn't specifically what I was referring to. More the overall different opinions here on what should be done. These debates go on among the industry experts.

I can guess what @JohnT may be referring to but he needs to be more specific. Debating it is not going to fix your problem. Finding the source of the electricty in the ground in your area will.
Click to expand...


Ok. I'm with you now and totally agree! Finding the source is what I am about to try and do. I have told my wife to go buy a permit today to get the inspector out and get that ball rolling. i am also going to contact my electric company guy.

As I read back, I didn't mean to quote you on that reply. I meant to quote @JohnT . I got the two replies confused there
 
Last edited:

Enjoying this content?

Support TFP with a donation.

Give Support
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply