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Swimming Pool Bonding

north star

north star

Sawhorse
Joined
Oct 19, 2009
Messages
4,596
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The topic of bonding the swimming pools keeps coming up for discussion in

this AHJ.

What we have typically been doing / requiring, on the In-Ground type of

Residential swimming pools, is to have a continuous #8 bare, copper

conductor attached to the swimming pool patio area, around the entire

perimeter of the pool, ...and attaching it to the various metal

components in & around the pool itself [ i.e. - any ladders, diving boards,

etc. ], as per Section E4104 of the `06 IRC.

Conundrum #1:

While attending some training classes, the instructor has always

taught that the #8 conductor should be routed back to the electrical

panelboard and terminated inside of it, ...similar to the bonding

requirements of gas piping.......According to code, where is the

bonding conductor "required" to be terminated? [ code section please ]

Conundrum #2:

In performing some reading / research on this topic, some other

forum members / guests have said that using the welded wire mesh /

welded wire fabric should NOT be useld as a means of "reinforcement"

in the swimming pool deck area, because the wwm / wwf ends up at

various locations in side the concrete placement area, and could / will

erode the #8 bonding conductor, ...thereby negating the perimeter

bonding grid.



Does the code actually specify the use of steel reinforcement bars,

that are actually fully supported from underneath, so as to prevent

sagging / displacement of the equipotential bonding grid?......IME [ in

my experience ], wwm / wwf in these type applications, by itself has

never been installed correctly.....Again, please cite the applicable

code section.



Ya'lls input is requested and GREATLY appreciated! :cool:

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north star said:
Conundrum #1:

While attending some training classes, the instructor has always

taught that the #8 conductor should be routed back to the electrical

panelboard and terminated inside of it, ...similar to the bonding

requirements of gas piping.......According to code, where is the

bonding conductor "required" to be terminated? [ code section please ]
Click to expand...
Here is some 2008 NECH commentary following 680.26;



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©.
Click to expand...
So the area above in red would indicate there is no need to extend the #8 to the supplying panelboard.



Conundrum #2:
Click to expand...
In performing some reading / research on this topic, some otherforum members / guests have said that using the welded wire mesh /

welded wire fabric should NOT be useld as a means of "reinforcement"

in the swimming pool deck area, because the wwm / wwf ends up at

various locations in side the concrete placement area, and could / will

erode the #8 bonding conductor, ...thereby negating the perimeter

bonding grid.



Does the code actually specify the use of steel reinforcement bars,

that are actually fully supported from underneath, so as to prevent

sagging / displacement of the equipotential bonding grid?......IME [ in

my experience ], wwm / wwf in these type applications, by itself has

never been installed correctly.....Again, please cite the applicable

code section.



Click to expand...
Doesn't need to be encased.

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.
Click to expand...
 
Doesn't need to be encased.

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.

To clarify a bit....rebar or structural steel will have minimum encasement in concrete....discussed recently in another thread.....
 
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Thank you Chris & steveray for your input!



MODERATOR: This topic should probably be moved to the Pools, Spas & Hot tubs thread.

Thanks!



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chris kennedy said:
Code section please.
Click to expand...
Chris, for the re-bar to be considered reinforcing steel in accordance with the building code it must meet the requirements of ACI 318 which requires a minimum concrete encasement of 2" for structural reinforcing steel.

Chris
 
Indeed, I learned a lot from your post because it contains a very valuable information. This is new to my knowledge and this post is really interesting. And now I'm looking for a post that tackled about the pool service equipment because we have a several problem in our swimming pool at home. By the way, Thank you very much for this post.
 
Indeed, I admire the valuable information given here. This is new to my knowledge and this post is really interesting. And now I'm looking for a post that tackled about the pool service equipment because we have a several problem in our swimming pool at home. By the way, Thank you very much for this post.
 
From my last quote in post 2;

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.
Click to expand...
 
raider1 said:
Chris, for the re-bar to be considered reinforcing steel in accordance with the building code it must meet the requirements of ACI 318 which requires a minimum concrete encasement of 2" for structural reinforcing steel.Chris
Click to expand...
Chris, did you read this in ACI 318 ? I just perused 318 and I can not find it.
 
1807.1.6.2 Concrete foundation walls.

Concrete foundation walls shall comply with the following: 1. The thickness shall comply with the requirements of Table 1807.1.6.2.

2. The size and spacing of vertical reinforcement shown in Table 1807.1.6.2 is based on the use of reinforcement with a minimum yield strength of 60,000 pounds per square inch (psi) (414 MPa). Vertical reinforcement with a minimum yield strength of 40,000 psi (276 MPa) or 50,000 psi (345 MPa) shall be permitted, provided the same size bar is used and the spacing shown in the table is reduced by multiplying the spacing by 0.67 or 0.83, respectively.

3. Vertical reinforcement, when required, shall be placed nearest the inside face of the wall a distance, d, from the outside face (soil face) of the wall. The distance, d, is equal to the wall thickness, t, minus 1.25 inches (32 mm) plus one-half the bar diameter, db, [ d = t - (1.25 + db / 2) ]. The reinforcement shall be placed within a tolerance of ± 3/8 inch (9.5 mm) where d is less than or equal to 8 inches (203 mm) or ± 1/2 inch (12.7 mm) where d is greater than 8 inches (203 mm).

4. In lieu of the reinforcement shown in Table 1807.1.6.2, smaller reinforcing bar sizes with closer spacings that provide an equivalent cross-sectional area of reinforcement per unit length shall be permitted.

5. Concrete cover for reinforcement measured from the inside face of the wall shall not be less than 3/4 inch (19.1 mm). Concrete cover for reinforcement measured from the outside face of the wall shall not be less than 11/2 inches (38 mm) for No. 5 bars and smaller, and not less than 2 inches (51 mm) for larger bars.

6. Concrete shall have a specified compressive strength, f 'c, of not less than 2,500 psi (17.2 MPa).

7. The unfactored axial load per linear foot of wall shall not exceed 1.2 t f 'c where t is the specified wall thickness in inches.

Item #5 - however, this would not apply to swimming pools
 
OH NO!

14585468928_a056d1ae16_h.jpg

It is now the next day. The contractor had a meeting with the office manager. He claims that since the pool is a liner pool, the equipotential bonding grid is not required. The job is old and the permit expired once already. There was no inspection of the perimeter grid so naturally, he is fighting the correction.
 
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"So the area above in red would indicate there is no need to extend the #8 to the supplying panelboard."

Had this discussion with one of my electrical inspectors.......I/we agree with Chris's statement, but in our case the #8 did extend to the board, and we determined that nothing prohibits it. One better or worse than the other?

 
27803314044_d20fee3a0e_b.jpg

28387118466_596779d353_b.jpg

I wrote a correction to move the split bolt to the long bar. Now I wonder if I should have asked for a ground clamp too.
 
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"I wrote a correction to move the split bolt to the long bar. Now I wonder if I should have asked for a ground clamp too."

Why?
 
I figured on the split bolt, but I was curious as to why move to the long bar? I am guessing it is not 18-24" from the inside of the pool? But it still could be the shorter bar.
 
Steveray, I think your correct, split bolt for splicing should not be used for grounding clamp, would need to be listed for burial when used on a rod or electrode. I have never seen a split bolt used to attach to a rod or re-bar.

Switching to a longer piece of 1/2-inch re-bar might be from the minimum length of 20-ft encased electrode requirement?? Just a guess.
 
The short bar is laying on the long bars with hardly any contact. For that reason I asked that the connection be moved. This is for the equipotential bonding grid (perimeter) so the grounding rules are not applicable. However I wasn't pleased with the split bolt so I called the contractor and asked that a rebar clamp be used.
 
MP1_91713.jpg
Rebar grounding clamp.
 
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