Swimming Pool/Hot Tub perimeter bonding grid 2011

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shortcircuit2

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It appears from the article I just read in EC&M that they have changed the altenate means for the fabrication of a perimeter bonding grid in the field from a single #8 conductor back to what was required in the 2005 code cycle which is the 12x12inch Network of #8 bonded at all points of crossing in the grid.

The article comments that "Fortunately, this provision isn't used often"

shortcircuit2
 
Swimming Pol/Hot Tub perimeter bonding grid 2011

Swimming Pol/Hot Tub perimeter bonding grid 2011

shortcircuit2 said:
It appears from the article I just read in EC&M that they have changed the altenate means for the fabrication of a perimeter bonding grid in the field from a single #8 conductor back to what was required in the 2005 code cycle which is the 12x12inch Network of #8 bonded at all points of crossing in the grid.

The article comments that "Fortunately, this provision isn't used often"

shortcircuit2
Click to expand...

Look at 680.26(B)(2)(b) 1-5 in the 2011 code. also the commentary in the handbook
 
The grid is required where structural reinforced steel is encapsulated in a nonconductive compound.680.26(B)(1)(a)
 
Swimming Pool/Hot Tub perimeter bonding grid 2011

Dennis Alwon said:
The grid is required where structural reinforced steel is encapsulated in a nonconductive compound.680.26(B)(1)(a)
Click to expand...

I agree, but IMO that does not apply to perimeter surfaces. Am I correct?
 
Well it is only my opinion. Here is what the article states and I believe it is incorrect.

The bonding grid must comply with (a) or (b) and be attached to the conductive pool reinforcing steel at a minimum of four points uniformly spaced around the perimeter of the walls of a pool, outdoor spa, or outdoor hot tub.

(a) Structural Reinforcing Steel. Unencapsulated structural reinforcing steel in concrete shells secured together by steel tie wires [680.26(B)(1)(a)].

(b) Alternative Copper Conductor Grid. Where the structural reinforcing steel isn’t available (or is encapsulated in a nonconductive compound, such as epoxy), an equipotential bonding grid meeting all of the following requirements must be installed (click here to see Fig. 19):

(1) The bonding grid must be 8 AWG solid copper, arranged in the manner described in 680.26(B)(1)(b)(3).

(2) The bonding grid must follow the contour of the perimeter surface extending 3 ft horizontally beyond the inside walls of pool.
(3) Listed splicing devices must be used.

(4) The grid must be secured in or under the deck or unpaved surface within 4 in. to 6 in. of the underside of the deck.
Click to expand...

The problem is that the NEC 2011 states "alternate means"-- not alternate means bonding grid. The above quote looks like part was taken from 680.26(B)(1)(b) which has nothing to do with perimeter surfaces.


NEC 2011 said:
(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 surfaces and other types of paving. Perimeter surfaces less than 1 m (3 ft) separated by a permanent wall or building 1.5 m (5 ft) in height or more shall require
equipotential bonding on the pool side of the permanent wall or building. 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.
(a) Structural Reinforcing Steel. Structural reinforcing steel shall be bonded in accordance with 680.26(B)(1)(a).
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 mm to 600 mm (18 in. 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
Click to expand...
 
Last edited:
Bump-- any feedback on this situation. The 2011 NEC seems to be different than what the author wrote in ec&m- or am I missing something.
 
Sorry regarding the original post...but it is what is written in the Nov. 2010 issue of EC+M...and there is even a MIKE HOLT picture (fig.19 on page 39) showing the 12x12 network in the perimeter surrounding the pool.
I do not have the 2011 code as I am waiting for the Massachusetts version...

shortcircuit
 
electricmanscott said:
I'm missing something, the article from the EC&M. ;)
Click to expand...

The article from ecm is the first quote in the #8 post. I will repost the ec&m article

EC&M said:
The bonding grid must comply with (a) or (b) and be attached to the conductive pool reinforcing steel at a minimum of four points uniformly spaced around the perimeter of the walls of a pool, outdoor spa, or outdoor hot tub.

(a) Structural Reinforcing Steel. Unencapsulated structural reinforcing steel in concrete shells secured together by steel tie wires [680.26(B)(1)(a)].

(b) Alternative Copper Conductor Grid. Where the structural reinforcing steel isn’t available (or is encapsulated in a nonconductive compound, such as epoxy), an equipotential bonding grid meeting all of the following requirements must be installed (click here to see Fig. 19):

(1) The bonding grid must be 8 AWG solid copper, arranged in the manner described in 680.26(B)(1)(b)(3).

(2) The bonding grid must follow the contour of the perimeter surface extending 3 ft horizontally beyond the inside walls of pool.
(3) Listed splicing devices must be used.

(4) The grid must be secured in or under the deck or unpaved surface within 4 in. to 6 in. of the underside of the deck.
Click to expand...
 
OK...so does all this mean that:

"Where the structural reinforcing steel isn?t available in the pool shell" you have to have the alternate 12x12inch grid fabricated to extend into the perimeter surface for 3 feet?

But if the pool has structural reinforcing steel...then all we have to do is install a single #8 bare copper wire bonded to the structure following the contour of the pool 18-24inches out and 4-6inches below the perimeter surface?

shortcircuit
 
Are you talking pool shell or perimeter surface. They are different and I think that is what the ec&m article has confused-- or at least confused me.
 
The article in the EC+M does comment that it is not something we see very often...that would be a pool with non-conductive structural reinforcing steel or none at all.

There is a pool built in my area that they use forms and pour the upright walls with reinforcing steel that is all bonded......BUT the floor/bottom is just concrete formed by hand over the subgrade without any reinforcing steel.....then a liner is installed over both floor and walls.

I'm thinking this alternate 12x12 grid is supposed to be in that concrete floor? According to the what the 2011 NEC says anyway....

I'm trying to sort this out...

shortcircuit
 
680.26 Equipotential Bonding.
(A) Performance. The equipotential bonding required by
this section shall be installed to reduce voltage gradients in
the pool area.
(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).
(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.
The bonding shall be in accordance with 250.8 or
other approved means.
(2) Conform to the contour of the pool
(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 surfaces and other types of paving. Perimeter
surfaces less than 1 m (3 ft) separated by a permanent
wall or building 1.5 m (5 ft) in height or more shall require
equipotential bonding on the pool side of the permanent
wall or building. 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.
(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 mm to 600 mm
(18 in. 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.
 
shortcircuit2 said:
I guess whats confusing me is the EC+M article...
Click to expand...

I will post the picture from ec&m.

011ecmCSfig19.gif


Now here is the problem. It appears to be talking about perimeter surfaces but then it quotes art. 680.26(B)(1)(b)(3) which is for bonding conductive pool shells, but it is also for when the perimeter surface has encapsulated steel in a nonconductive compound.

Art. 680.25(B)(2)(a) reference 680.26(B)(1)(a) which in turn references the copper grid.

The problem here is twofold as I see it.
1. The title from EC&M -- 680.26 Equipotential Bonding
The requirements for swimming pool bonding were revised?again.

2. I do not see this as a change and there is an alternative means which is to use a single conductor as stated in alternative means in 680.26(B)(2)(b). So yes you can do the grid but it appears you can also choose to do the single conductor. It seems the grid can be used but doubtful anyone would use it given the choice.

The only change I see in perimeter surfaces is this sentence

NEC 2011 said:
Perimeter surfaces less than 1 m (3 ft) separated by a permanent wall or building 1.5 m (5 ft) in height or more shall require equipotential bonding on the pool side of the permanent wall or building.
Click to expand...
 
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