Here's one for you.

If equipotential bonding is a fix for stray currents, then why isn't equipotnetial bonding an option in Section 250.6 or required by any other section of Article 250?

Also, a pool is not required to have electrical equipment at all. You can install a pool in the middle of an open field in the middle of nowhere, and you would still have to install an equipotential bonding grid. WHY? Because the voltage is created by the pool, not from a remote source.

The same would apply to agricultural buildings with livestock. The voltage gradient is produced by the portential between the steel re-enforced concrete and metal parts of the building. The cow becomes the circuit. The equipotential bonding required Article 547 is mandatory whether or not a premise wiring system is present at the building or not.

Bryan, I completely agree with your take on the equipotnetial bonding requirment but I have to ask where is it mandatory that this be installed where there is no electrical? ART. 547?

John,

It is because the grid is for stray voltages and as we know cattle have a natural tendency to stray - ha ha ha ha

No seriously, though.

The telluric currents are going to get you LOL

680.26 - All the parts in (B)(1) - (7) and (C) must be bonded together. there is nothing in this section or anywhere else in the code that states that 680.26 rules are expempt to a non-electric pool.


So for example. Let's say someone builds a concrete pool, with a concrete deck, and has metal handrials. This pool is located in the middle of field with no other building within 10 miles. There is no electric serving the property or supplying the pool.

Does 680.26 still apply? YES! You still need to bond the shell, perimeter surfaces, metal rails and cups, and the pool water together. WHY? Becuase voltage grdients will be produced by the pool materials and not some other remote source.

LOL!!! Falling out of my chair. That's a good one.

Back in the day when I was a contractor. I never could see this as a issue until I wired the mile long pool in Hillsborough. Today I guess they call them river pools.
The site was still on a saw pole so the service was not energized.
As we started to connect the #8 bond to each of the 15 or so pumps.
You would see a small arc. It was a little dark in the room(no power).
When I connected the first one I was startled to see the spark. Thinking something wrong here I checked it with my fluke. I don't remember the voltage but I do remember that there was some minor voltage there compared to the ground. Not 120volts but still very high So I thought temporary power was connected to the service. And it was hosed up.
But no.
Since then I am convinced it it is a necessary item.

In fact Neal way back when in tampa when red tag baggot was around. he he!! On commercial pools. If it had a metal fence around the pool it was bonded even if it was 30 foot away from the pool edge. He required each fence post to be bonded. Let me tell you adding 30 to 50 2" jweaver clamps besides the extra #8 was not in the job cost.

All I asked was if you all were enforcing 680.10 on PVC associated with the pool.
And I think Bryan, Nick, Paul C, and Paul N all say 680.10 applies to other counduts less than 5' outside edge of pool, but we are so off topic I cannot tell.

I guess we just cannot help ourselves.
Bryan, would not a #2 "ground ring" installed as part of the grounding electrode system be the same as the #8 around a pool(which is required by the code, but no one enforces)?
There is also big difference between Equipotential Bonding in 680 and the Equipotential Plane required in 547. I agree that a bond ring is required at items covered by 680 whether or not it has electric service. From Article 680 in the 2008 Handbook "The installations covered by this article can be indoors or outdoors, permanent or storable, and may or may not be directly supplied by electrical circuits of any nature".
But Article 547 differs;
The Equipotential Plane is only required in confinement areas with concrete floors where metallic equipment is located that may become energized and is accessible to livestock.
This plane is only required where metallic equipment may become energized, so I would say it would have to have electrical service to become energized.
This #8 must be connected to the electrical grounding system (which differs from 680)to prevent a difference in voltage from developing within the plane.
So I have to ask if voltage is developed in the Equipotential Plane installed under 547 where would the voltage go?

IMHO
Neal Burdick
City of Tampa
Construction Inspector II

Hey there Y'all,

This is certainly an interesting topic. As a matter of general information, when setting up the field equations for voltage gradients about a swimming pool, one must also include a formula contribution for "voltage gradients in open air." So it would seem that Mr. Sasso's comment along with picture about the bird on a wire, really does have some relevance to the subject.

Dick Widera
Secretary, Suncoast Division IAEI

No. The purpose and function of the grounding electrode system is completely different than the purpose of the equipotential bonding grid.

The purpose of "grounding" is identified in section 250.4(A)(1), wheras the purpose of the equipotential bond is identified in Section 680.26(A). So you may be asking, what is the difference?

Grounding is to limit the voltage imposed on the premise wiring system from an EXTERNAL SOURCE, with lightning being the primary contributor. Euipotential bonding is to limit the voltage at and around the pool from an INTERNAL SOURCE, the pool parts and materials themselves.

Like with equipotential bonding, grounding doesn't dissipate anything. Until the source is removed or de-energized, the possibility of a difference in potential is created, thus resulting in surge currents on parts NOT INTENDED TO CARRY CURRENT.

The ground ring was developed to allow for several lightning down conductors to be attached to the earth and provide a means for establishing a counterpoise at a building or structure. The perimeter bonding ring was established to allow for the 4-point connection from the conductive pool shell and to provide equipoential bonding of the perimeter surfaces fully around the pool, 3 feet out.




You have to go back to your theory days to remember that voltage is only the pressure or potential that is present between two or more objects. The only way to ensure no potential is present between two objects is to electrically bond them together. This way, no current can flow between those two objects using a humnan, or in this case, cattle as the circuit.

I guess this is good time to point out that we are indeed talking about THEORY and not LAW or FACT. We could all be wrong...