# equipotential bonding grid (pool)



## njspark83 (May 11, 2009)

Doing a basic above ground pool. How do I go about installing the equipotential bonding grid and what fittings do I need. I have read the article. thanks.


----------



## Innovative (Jan 26, 2010)

Since you are in NJ and I am in Fl, I am not gonna touch this one. The last few weeks I have seen some odd bonding grids, or lack of any bonding grids for pools on this forum. However, I have done mainly concrete inground pools(over 2,500), but to me a bonding grid is a bonding grid. I can tell you this, we do it way different down here in the "Sunshine State".


----------



## Toronto Sparky (Apr 12, 2009)

I really don't get this pool bonding thing all of a sudden.
What is it's purpose? To make you a better target for lightning?
Any electrical anywhere near the pool is bonded and on GFI 
Where does this potential that needs to be drained come from?


----------



## electricmanscott (Feb 11, 2010)

For a standard above ground pool you would run a solid bare #8cu around the pool about 18-24 inches out from the edge. It should be buried in the ground 4-6 inches. It also has to connect to the pool at 4 locations, the motor, and the pool water.

I use a lay in lug rated for direct burial nut and bolted to the bottom of the pool wherever I can get it to connect the bond to the pool.


Water bond...
http://www.bondsafe680.com/about.html


----------



## electricmanscott (Feb 11, 2010)

Toronto Sparky said:


> I really don't get this pool bonding thing all of a sudden.
> What is it's purpose? To make you a better target for lightning?
> Any electrical anywhere near the pool is bonded and on GFI
> Where does this potential that needs to be drained come from?


This is nothing new really. There have been variations of required bonding for as long as I can remember.

The purpose is pretty simple. Eliminate voltage gradients in the pool area. This includes the ground around the pool. If you have a pool that is properly bonded/grounded and you have stray voltage in the ground and you are wet and barefoot guess what happens if you touch the pool. The same thing applies to any conductive surface in the pool area that is not bonded.


----------



## JayH (Nov 13, 2009)

Toronto Sparky said:


> I really don't get this pool bonding thing all of a sudden.
> What is it's purpose? To make you a better target for lightning?
> Any electrical anywhere near the pool is bonded and on GFI
> Where does this potential that needs to be drained come from?


Ever hear of or encountered a failed GFCI?

We're talking a contained body of water with humans floating around inside.


There's your potential.


----------



## njspark83 (May 11, 2009)

i dont see where it actually says 4 points in the code. code number??


----------



## Innovative (Jan 26, 2010)

680.26 Equipotential Bonding.
(A) Performance. The equipotential bonding required by this section shall be installed to reduce voltage gradients in the pool area.
It is important to understand the difference between the terms bonding and grounding as they apply to Article 680. As defined in Article 100, bonding is “connected to establish electrical continuity and conductivity.” As described in 680.26(A), the function of equipotential bonding differs from the primary function of bonding to meet the requirements of Article 250 in that providing a path for ground-fault current is not the function of the equipotential bonding grid and associated bonding conductors.
Creating an electrically safe environment in and around permanently installed swimming pools requires the installation of a bonding system with the sole function of establishing equal electrical potential (voltage) in the vicinity of the swimming pool. A person who is immersed in a pool or who is dripping wet, has a large amount of exposed skin, and is lying or walking on a concrete deck or other conductive perimeter surface is extremely vulnerable to any differences in electrical potential that may be present in the pool area.
The primary purpose of bonding in and around swimming pools is to ensure that voltage gradients in the pool area are not present. Section 680.26(B) specifies that the 8 AWG conductor's only function is equipotential bonding to eliminate the voltage gradient in the pool area and the bonding conductor is not required to extend or connect to any parts or equipment other than those covered in 680.26(B)(1) through (B)(7) and to a pool water bonding element covered in 680.26(C).
The reason for electrically connecting all of the metal parts described in 680.26(B)(1) through (7) is to ensure that they all are at the same electrical potential. This bonding reduces possible injurious or disabling shock hazards created by stray currents in the ground or piping connected to the swimming pool. Stray currents can also exist in nonmetallic piping because of the low resistivity of chlorinated water. See Exhibit 680.10.

Exhibit 680.10 Bonding of conductive metal parts in a swimming pool.
(B) Bonded Parts. The parts specified in 680.26(B)(1) through (B)(7) shall be bonded together using solid copper conductors, insulated covered, or bare, not smaller than 8 AWG or with rigid metal conduit of brass or other identified corrosion-resistant metal. Connections to bonded parts shall be made in accordance with 250.8. An 8 AWG or larger solid copper bonding conductor provided to reduce voltage gradients in the pool area shall not be required to be extended or attached to remote panelboards, service equipment, or electrodes.
(1) Conductive Pool Shells. Bonding to conductive pool shells shall be provided as specified in 680.26(B)(1)(a) or (B)(1)(b). Poured concrete, pneumatically applied or sprayed concrete, and concrete block with painted or plastered coatings shall all be considered conductive materials due to water permeability and porosity. Vinyl liners and fiberglass composite shells shall be considered to be nonconductive materials. 
(a) Structural Reinforcing Steel. Unencapsulated structural reinforcing steel shall be bonded together by steel tie wires or the equivalent. Where structural reinforcing steel is encapsulated in a nonconductive compound, a copper conductor grid shall be installed in accordance with 680.26(B)(1)(b).
Conductive pool shells include those constructed of poured concrete, pneumatically applied concrete, concrete block, and, of course, metal. Fiberglass and vinyl-lined pools are not considered to be conductive pool shells and are not subject to having a bonding grid installed around the entire contour of the pool shell.
Encapsulated reinforcing steel is not likely to provide the conductivity necessary to establish the required common bonding grid around the contour of a conductive pool shell. A bonding grid around the contour of the pool shell will not be formed if the steel is effectively encapsulated by a listed compound during installation and manufacturing. Therefore, a bonding connection to the encapsulated reinforcing steel is not required; however, a bonding grid around the contour of a conductive pool shell must be provided. The copper bonding grid is required to be constructed as prescribed in 680.26(B)(1)(b). See Exhibit 680.11.

Exhibit 680.11 Epoxy-coated rebar, which does not require bonding.
In Exhibit 680.12, structural reinforcing steel serves as a common point to which all metal appurtenances associated with the pool are connected. This method of connection is one way of satisfying the requirement to bond all metal parts together. Individual pieces of hardware such as the hooks used to attach safety or lane ropes, that are less than 4 in. in any dimension and do not penetrate into the pool structure more than 1 in. are not required to be bonded, per 680.26(B)(5). The flush deck box meets the provisions of 680.24(A).

Exhibit 680.12 A poured-concrete pool with structural reinforcing steel that serves as the pool shell bonding grid. 
(b) Copper Conductor Grid. A copper conductor grid shall be provided and shall comply with (b)(1) through (b)(4). 
(1) Be constructed of minimum 8 AWG bare solid copper conductors bonded to each other at all points of crossing 
(2) Conform to the contour of the pool and the pool deck 
(3) Be arranged in a 300-mm (12-in.) by 300-mm (12-in.) network of conductors in a uniformly spaced perpendicular grid pattern with a tolerance of 100 mm (4 in.) 
(4) Be secured within or under the pool no more than 150 mm (6 in.) from the outer contour of the pool shell 
(2) Perimeter Surfaces. The perimeter surface shall extend for 1 m (3 ft) horizontally beyond the inside walls of the pool and shall include unpaved surfaces as well as poured concrete and other types of paving. Bonding to perimeter surfaces shall be provided as specified in 680.26(B)(2)(a) or (2*)(b) and shall be attached to the pool reinforcing steel or copper conductor grid at a minimum of four (4) points uniformly spaced around the perimeter of the pool.* For nonconductive pool shells, bonding at four points shall not be required.
The requirement for bonding perimeter surfaces now applies to paved and unpaved surfaces. An example of an unpaved perimeter surface would be the lawn surrounding a permanently installed aboveground swimming pool. Where the paved portion of the perimeter surface extends less than 3 ft horizontally from the inside walls of the pool, the perimeter bonding grid must be continued under the adjacent unpaved perimeter surface. If physical constraints (such as a wall or other physical barrier) prevent the perimeter from extending 3 ft beyond the inside walls of the pool, the bonding grid is required only to extend under the available perimeter area.
The perimeter bonding grid can be comprised of structural reinforcing metal (re-bar or welded wire mesh) that is conductive to the perimeter surface and installed in or under the perimeter surface. Where structural reinforcing steel is not available, a single, bare, solid 8 AWG or larger copper conductor can be installed around the perimeter of the pool in an area measuring between 18 in. and 24 in. from the inside pool walls. This 8 AWG bonding conductor can be installed in the paving material (i.e., in the concrete), or it can be buried in the material (subgrade) below the paving material. Where buried, the bonding conductor is to be not less than 4 in. and not more than 6 in. below the surface level of the subgrade material.
The perimeter surface bonding medium has to be connected, at four evenly spaced points around the pool perimeter, to either the structural steel of a conductive pool shell or to the copper bonding grid provided for the conductive pool shell that has encapsulated re-bar or no re-bar at all. Connection between the perimeter bonding medium and nonconductive pool shells is not required.

(a) Structural Reinforcing Steel. Structural reinforcing steel shall be bonded in accordance with 680.26(B)(1)(a). 
(b) Alternate Means. Where structural reinforcing steel is not available or is encapsulated in a nonconductive compound, a copper conductor(s) shall be utilized where the following requirements are met: 
(1) At least one minimum 8 AWG bare solid copper conductor shall be provided. 
(2) The conductors shall follow the contour of the perimeter surface. 
(3) Only listed splices shall be permitted. 
(4) The required conductor shall be 450 to 600 mm (18 to 24 in.) from the inside walls of the pool. 
(5) The required conductor shall be secured within or under the perimeter surface 100 mm to 150 mm (4 in. to 6 in.) below the subgrade.


----------



## TheRick (Apr 13, 2008)

So if an above ground pool has a wooden deck surrounding it could I staple a #8 bare to the underside of the deck? :laughing:


----------



## RIVETER (Sep 26, 2009)

TheRick said:


> So if an above ground pool has a wooden deck surrounding it could I staple a #8 bare to the underside of the deck? :laughing:


With jumpers to each nail.


----------



## Toronto Sparky (Apr 12, 2009)

I was wondering about the vinyl liner that all above ground pools tend to have.. 
Added to that you have (in my case) an 18ft above ground that has 56+ Feet of metal sitting on/partly in the ground isolated from the water by a vinyl liner.
Seems to me the important part would be to make sure the water itself is at the same potential as the metal railing surrounding the pool.

Assuming the GFI has failed and the power is travelling though the water (ABS piping)
then the water could be at different potential.

At the same time the building ground itself would be at different potential then the area surrounding the pool. 

So I'm guessing the only safe way is to run the bonding cable to everything that can conduct in one continuous run to bring everything to the same potential. 

Then again that may even include the water sitting on your wooden deck..

Hmmm


----------



## RIVETER (Sep 26, 2009)

All of the safety as far as the grounding and bonding goes probably won't help you much if you are in the pool during a direct lightning strike. Phase to ground faults are a different story.


----------



## njspark83 (May 11, 2009)

what page is exhibit 680.12A its not in my paperback 2008 nec


----------



## electricmanscott (Feb 11, 2010)

Toronto Sparky said:


> I was wondering about the vinyl liner that all above ground pools tend to have..
> Added to that you have (in my case) an 18ft above ground that has 56+ Feet of metal sitting on/partly in the ground isolated from the water by a vinyl liner.
> Seems to me the important part would be to make sure the water itself is at the same potential as the metal railing surrounding the pool.
> 
> ...



The water is required to be bonded as well.


----------



## Magnettica (Jan 23, 2007)

njspark83 said:


> what page is exhibit 680.12A its not in my paperback 2008 nec


That's from the '08 NEC Handbook. :thumbsup:


----------



## leland (Dec 28, 2007)

njspark83 said:


> i dont see where it actually says 4 points in the code. Code number??



2008 nec- 680.26(b)(2)


----------



## leland (Dec 28, 2007)

electricmanscott said:


> The water is required to be bonded as well.



For vinyl and fiberglass yes. 2008 NEC- 680.26(B)(1)


----------



## electricmanscott (Feb 11, 2010)

electricmanscott said:


> The water is required to be bonded as well.





leland said:


> For vinyl and fiberglass yes. 2008 NEC- 680.26(B)(1)


Huh? :001_huh:


----------

