Another TIA for Perimeter Bonding

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
This is going to be a costly change as now the single #8 running around the contour of the pool 18-24" away 4-6 " below subgrade will only apply to above ground pools.

NFPA 70®-2020 and Proposed 2023 Editions National Electrical Code® TIA Log No.: 1661 Reference: 680.26(B)(2)(b) Comment Closing Date: July 7, 2022 Submitter: Thomas Kilpatrick, Kilpatrick Law Group, PLLC www.nfpa.org/70 1. Revise paragraph 680.26(B)(2)(b) to read as follows: 680.26 Equipotential Bonding. (A) Performance. … (B) Bonded Parts. … (1) Conductive Pool Shells. … (2) Perimeter Surfaces. … (a) Structural Reinforcing Steel. … (b) Copper Ring. … (1) … (2) … (3) … (4) … (5) … This method shall only be permitted for aboveground pools. (c) Copper Grid. … (3) Metallic Components. … Substantiation: Article 680.26B is dangerously insufficient with regards to in-ground pools. The deficiency is that a single bonding wire does not offer adequate protection against electric shocks. Two new reports show that a bonding grid, as prescribed in Art. 680.26B(2)(a) and/or 680.26(B)(2)(c), that is connected to the swimming pool deck and other conducting objects in the pool area -- rather than a single wire -- provides the suitable level of protection against these shocks. Emergency Nature: The proposed TIA intends to offer to the public a benefit that would lessen a recognized (known) hazard or ameliorate a continuing dangerous condition or situation. The proposed TIA intends to correct a circumstance in which the revised NFPA Standard has resulted in an adverse impact on a product or method that was inadvertently overlooked in the total revision process or was without adequate technical (safety) justification of the action. Two new reports by the Electric Power Research Institute (“EPRI”) with measurements being taken and/or verified by Duke Energy. These are examples of two residential pools in North Carolina that were built with adherence to the NEC, in compliance with Article 680.26(B)(2)(b). However, after completion, painful shock voltages existed between the water and the pool deck, the bonded ladder and the pool deck, the bonded handrail and the pool deck. This clearly demonstrates that the pool deck cannot be brought to the equipotential of the other bonded surfaces by using the single copper bonding wire specified in (B)(2)(b). Anyone contacting one of those bonded parts and the pool deck simultaneously experienced shocking to the level of physical pain and the generation of tremendous fear. Brand new pools were hazardous and unusable, so the experts from EPRI were called in to determine the problem and the solution. At both of these pools, the homeowners were experiencing perceptible burning sensations between the pool water and the pool decks around the pool. At these two pools, EPRI measured voltage differences between the water and decks in the range of 2 Vac to 10 Vac. Moreover, these voltage levels can be demonstrated to increase to and decrease over the course of a day or a week thereby violating the equipotential objects and surfaces intent of NEC Article 680.26. Of most concern is the voltage differences at these two pools that are (B)(2)(b) compliant, can be demonstrated to go to full line voltage during fault conditions and the shock currents under those conditions exceed known human fibrillation levels. In each of the homeowner’s situations, the single wire prescribed in 680.26(B)(2)(b) was installed, but failed to provide adequate protection. Therefore, brand new concrete pool decks had to be destroyed and removed and copper equipotential bonding grids installed per Art. 680.26 (B)(2)(c), and then new pool decks were installed. After the installation of the bonding grid, the measured voltage differences between the bonded parts and the deck are insignificant and the homeowners have not experienced any further electrical shock and can safely use their pools. EPRI’s testing proves the situation as hazardous with the single wire, yet completely safe with a bonding grid. Anyone may submit a comment by the closing date indicated above. Please identify the TIA number and forward to the Secretary, Standards Council.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
The part I find interesting is the part in red. I just hope that one of those pools cited wasn't the one here in Raleigh where the lifeguard got electrocuted. That clearly was illegal and dangerous work done by the electrical contractor.

Two new reports by the Electric Power Research Institute (“EPRI”) with measurements being taken and/or verified by Duke Energy. These are examples of two residential pools in North Carolina that were built with adherence to the NEC, in compliance with Article 680.26(B)(2)(b). However, after completion, painful shock voltages existed between the water and the pool deck, the bonded ladder and the pool deck, the bonded handrail and the pool deck. This clearly demonstrates that the pool deck cannot be brought to the equipotential of the other bonded surfaces by using the single copper bonding wire specified in (B)(2)(b).
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
There were proposals to this effect that were soundly rejected by CMP 14, so I have my doubts they will accept this TIA. If accepted the only perimeter bonding that would be acceptable for an in-ground pool, would be the copper ground grid in or below the surface materials.

Mike's video where he energized the pool showed that even a high resistance connection is sufficient to create the equal potential that is required.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
There were proposals to this effect that were soundly rejected by CMP 14, so I have my doubts they will accept this TIA. If accepted the only perimeter bonding that would be acceptable for an in-ground pool, would be the copper ground grid in or below the surface materials.

Mike's video where he energized the pool showed that even a high resistance connection is sufficient to create the equal potential that is required.


We will see. I wonder if the other proposals had EPRI study quoted. That may make a difference. I realize the grid would be the only way but that will be quite expensive.
 

EnduroManDan

Member
Location
USA
Occupation
Electrician
Can someone tell me what minimum requirements on gauge size for the “bonding grid” and how it needs to be installed when there is grass coverage only, no hardscapes?
 
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Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
2017 NEC
(2) Perimeter Surfaces. The perimeter surface
shall be considered to extend for 1 m (3 ft) horizontally
beyond the inside walls of the pool and shall include unpaved
surfaces and other types of paving. Perimeter surfaces separated
from the pool by a permanent wall or building 1.5 m (5 ft)
in height or more shall require equipotential bonding only 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.


2020


(2) Perimeter Surfaces.
The perimeter surface to be bonded shall be considered to extend for 1 m (3 ft) horizontally beyond the inside walls of the pool and shall include unpaved surfaces and other types of paving. Perimeter surfaces separated from the pool by a permanent wall or building 1.5 m (5 ft) in height or more shall require equipotential bonding only 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), (B)(2)(b), or (B)(2)(c) and shall be attached to the pool reinforcing steel or copper conductor grid at a minimum of four 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)
    Copper Ring. 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 splicing devices or exothermic welding 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.

  • (c)
    Copper Grid. Where structural reinforcing steel is not available or is encapsulated in a nonconductive compound, copper grid shall be utilized where the following requirements are met:
    • (1)
      The copper grid shall be constructed of 8 AWG solid bare copper and be arranged in accordance with 680.26(B)⁠(1)⁠(b)⁠(3).
    • (2)
      The copper grid shall follow the contour of the perimeter surface extending 1 m (3 ft) horizontally beyond the inside walls of the pool.
    • (3)
      Only listed splicing devices or exothermic welding shall be permitted.
    • (4)
      The copper grid shall be secured within or under the deck or unpaved surfaces between 100 mm to 150 mm (4 in. to 6 in.) below the subgrade.
 

EnduroManDan

Member
Location
USA
Occupation
Electrician
2017 NEC



2020
So on an above ground “concrete” pool, the single continuous #8 ran around the pool and back to the equipment is connected to the rebar on the pool shell on all four sides of the pool but also kept the 18”-24” around the pool. There is no deck so it will be some artificial grass around the pool. What size “bonding grid” needs to be under the artificial grass?
 

EnduroManDan

Member
Location
USA
Occupation
Electrician
So on an above ground “concrete” pool, the single continuous #8 ran around the pool and back to the equipment is connected to the rebar on the pool shell on all four sides of the pool but also kept the 18”-24” around the pool. There is no deck so it will be some artificial grass around the pool. What size “bonding grid” needs to be under the artificial grass?

I guess what I’m asking is, if the concrete shell cage connected all four sides does there still need to be a grid where the grass will be? If so, it needs to be #8 copper 12” square grid? Inspector told me it had to be #8 copper grid. Takes me down the street to show me another pool. It was just #10 reinforced steel mesh (like the put in concrete decks) And told me that’s what he wanted on my pool. Ok. I get it he’s the AHJ but I feel like this is a real grey area. I was electrician 15 years before getting in the pool business so I know there are always going to be codes with grey areas.
 

don_resqcapt19

Moderator
Staff member
Location
Illinois
Occupation
retired electrician
Your choice of (a), (b), or (c) for the perimeter bonding under the 2020 code. The 2017 code only has (a) or (b). In either case a single 8 AWG copper conductor is compliant.
 

Dennis Alwon

Moderator
Staff member
Location
Chapel Hill, NC
Occupation
Retired Electrical Contractor
So on an above ground “concrete” pool, the single continuous #8 ran around the pool and back to the equipment is connected to the rebar on the pool shell on all four sides of the pool but also kept the 18”-24” around the pool. There is no deck so it will be some artificial grass around the pool. What size “bonding grid” needs to be under the artificial grass?
#8 is for the bonding
 

mtnelect

HVAC Contractor
Location
Southern California
Occupation
Contractor
The pool was completed in 1988 and only bonded with No. 8 to all fixtures and no GFCI breakers. Seems like turning off all the power when in use is a smart decision.
 

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ActionDave

Chief Moderator
Staff member
Location
Durango, CO, 10 h 20 min without traffic from wing
Occupation
Licensed Electrician
Would you want to restrict the rule to private pools or include public pools?

Would that mean that public pools would be the ones that are controlled by counties and cities and not include hotels and condos?

Is it safer to have a pool with no lights as opposed to one with a light on. Lights off = no power, it also equals low vision. I could easily see a person that in a drunken stupor fell into a pool if there was a light on inside the water. I could not so easily see a person in the water if the pool was dark. Do you have any stats comparing drownings in a pool with no power present vs drownings in a pool with power present?

With no power while pools were in use it would mean that pool pumps would have to be turned off. How many kids pee in the pool? More than a few brown headed turtles poke out as well. Any chance there are some comparisons on death by infection vs death by electrocution out there? I know e coli is a big deal.
 

mtnelect

HVAC Contractor
Location
Southern California
Occupation
Contractor
Would you want to restrict the rule to private pools or include public pools?

Would that mean that public pools would be the ones that are controlled by counties and cities and not include hotels and condos?

Is it safer to have a pool with no lights as opposed to one with a light on. Lights off = no power, it also equals low vision. I could easily see a person that in a drunken stupor fell into a pool if there was a light on inside the water. I could not so easily see a person in the water if the pool was dark. Do you have any stats comparing drownings in a pool with no power present vs drownings in a pool with power present?

With no power while pools were in use it would mean that pool pumps would have to be turned off. How many kids pee in the pool? More than a few brown headed turtles poke out as well. Any chance there are some comparisons on death by infection vs death by electrocution out there? I know e coli is a big deal.

I am really surprised; I thought my suggestion would be a "No Starter".

Your suggestions:
1. Lighting: Seems like low voltage lighting would be safer.
2. Drownings: From what I have read, it always was with power on, except for marinas.
 
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