2008 looks like it will be satisfied with the wire mesh
2008 looks like it will be satisfied with the wire mesh
a quick Google search brings this up.
looks like the 2005 NEC needed the rebar
2008 looks like it will be satisfied with the wire mesh
the pool was probably built in 1970!
but the ADA lift chair is going in 2014
NEC 2005, 680.26(C) Equipotential Bonding Grid. The parts specified in 680.26(B) shall be connected to an equipotential bonding grid with a solid copper conductor, insulated, covered, or bare, not smaller than 8 AWG or rigid metal conduit of brass or other identified corrosion-resistant metal conduit. Connection shall be made by exothermic welding or by listed pressure connectors or clamps that are labeled as being suitable for the purpose and are of stainless steel, brass, copper, or copper alloy. The equipotential common bonding grid shall extend under paved walking surfaces for 1 m (3 ft) horizontally beyond the inside walls of the pool and shall be permitted to be any of the following:
(1) Structural Reinforcing Steel.
The structural reinforcing steel of a concrete pool where the reinforcing rods are bonded together by the usual steel tie wires or the equivalent (This is not wire mesh
(2) Bolted or Welded Metal Pools. The wall of a bolted or welded metal pool
(3) Alternate Means. This system shall be permitted to be constructed as specified in (a) through (c):
a. Materials and Connections. The grid shall be constructed of minimum 8 AWG bare solid copper conductors. Conductors shall be bonded to each other at all points of crossing. Connections shall be made as required by 680.26(D).
b. Grid Structure. The equipotential bonding grid shall cover the contour of the pool and the pool deck ex-tending 1 m (3 ft)horizontally from the inside walls of the pool. The equipotential bonding grid shall be arranged in a 300 mm (12 in.) by 300 mm (12 in.) network of conductors in a uniformly spaced perpendicular grid pattern with tolerance of 100 mm (4 in.).
c. Securing. The below-grade grid shall be secured within or under the pool and deck media.
You need to know, that this bonding is very important because unless the entire area is brought to the same potential by bonding (hence the name, "equipotential bonding"), then users of the pool are at risk of shock whenever they touch unbonded metallic components of the pool. In addition, the grid is to minimize "step potential" which, as it sounds, is to eliminate the chance that dangerous voltage can travel from one bare foot, through the user's body, out the other foot, due to a difference in potential over a few feet. This is why the grid is required for three feet around the pool.
You might be thinking, 'No big deal, there's no lights or electrical equipment in my pool anyway. I can skip this.' If there is no electrical equipment in the pool itself, you're still not out of the woods, believe it or not. A problem with a local utility company can generate "transient voltages", because the utility uses the earth in their systems too. So a failure of some kind in your service, or your neighbor's service, can result in current passing through the soil in your backyard seeking it's source at the local transformer, or a remote substation, depending on the problem.
People immersed in water are very vulnerable to current, as saturated skin is an excellent conductor.
I'm not blowing smoke, not trying to frighten you, not trying to score a sale. You should find a qualified electrician to help you. A pool is just no small matter.
Read more:
http://www.doityourself.com/forum/e...ing-without-rebar-concrete.html#ixzz2wXzWFheM
on the other hand:
As an individual looks at the whole picture associated with this equipotential bonding grid, we have to start to put the requirements together in order to meet the minimum standards of the National Electrical Code. From Article 680.26(C) an individual knows that they have three options to create this equipotential bonding grid system. They also know that whichever equipotential bonding grid system they employ it will have to extend a minimum of three feet horizontally from the inside walls of the pool and under paved walking surfaces. However, what if I do not have any paved walking surfaces. I should have a situation that does not require an equipotential bonding grid system to be installed horizontally 3-foot from the inside walls of the pool.
If method one is used an individual has to extend the reinforcing steel from the contour of the pool to a horizontal distance three feet from the inside wall of the pool. This will allow the equipotential bonding grid to meet the requirements of incorporating the paved walking surfaces within its boundary. If method two (typical pool construction) is employed an individual will have to connect to the walls of a bolted or welded metal pool by a permitted method described in Article 680.26(C). However, an individual will still have to extend 3-feet horizontally from the inside walls of the pool. This is another debated and confusion area within Article 680.26 and is clarified in the 2008 NEC.
The issue is what conductive material does an individual use to construct the equipotetnial bonding grid in these typical pool installations that is required to extend 3 feet horizontally from the inside walls of the pool. If I use the alternative means describe in part three, the bonding grid system is permitted to be constructed as spelled out in (a) through (c). This would mean that I am using a minimum #8 bare solid copper conductor to make my grid and that I have to construct my grid as per (b) and secure it as per (c). This is where the debate comes in.
Does an electrical contractor have to use rebar for this 3-foot extension area or can they use wire mesh. What about a #8 equipotential bonding grid ring? The goal is to equal out all the points so that there is no point at a difference within the pool or water area.
As I have mentioned, the
2008 National Electrical Code is further clarifying the explanation of the equipotential bonding grid. At this point the 2005 National Electrical Code has issued a Tentative Interim Amendment (TIA) (05-02 Log No. 821) to handle the problems and concerns associated with Article 680.26(C). This (TIA) will be the new terminology and installation requirement for the equipotetntial bonding grid system. As I have always stated, the wording was incorrect in the 2005 NEC in relationship to the term paved-surface. This is now an exception to Article 680.26(C) that provides the explanation and installation requirements for the 3 foot horizontal equipotential bonding grid under these types of surfaces.
The exception to Article 680.26(C) states ?The equipotential bonding grid shall not be required to be installed under the bottom or vertically along the walls of the vinyl lined polymer walls, fiberglass composite, or other pools constructed of nonconductive materials. Any metal parts of the pool, including metal structural supports, shall be bonded in accordance 680.26(B). For the purposes of this section, poured concrete, pneumatically applied (sprayed) concrete, and concrete block, with painted or plastered coatings, shall be considered conductive materials.? There is also some additional wording that has been added to 680.26(C)(1) that states ?Where deck reinforcing steel is not an integral part of the pool, the deck reinforcing steel shall be bonded to other parts of the bonding grid using a minimum #8 solid copper conductor. Connection shall be made as per 680.26(D).?
New additions to Article 680 are Article 680.26(B)(1)(a) that looks at the requirements of unencapsilated structural reinforcing steel and the fact that it shall be bonded together by steel ties 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). Article 680.26(B)(1)(b) also states that the copper conductor grid shall be constructed of a minimum #8 solid copper conductors bonded to each other at crossing points. It also requires the grid to conform to the contours of the pool shell and pool deck and shall be arranged in a (12 inch x 12 inch) network pattern with a 4-inch tolerance for spacing.
Article 680.26(B)(2)(b) addresses the perimeter surfaces of the pool area and requires at least one #8 solid copper conductor to be secured within or under these surfaces (18 ? 24) inches measured horizontally from the inside walls of the pool. If this conductor is installed beneath the final grade material, the bonding conductor is required to be buried (6 ? 8) inches below the subgrade.
This article also permits the bonding grid to be a single #8 solid copper conductor, wire mesh (547.10(B)), or rebar in the concrete. Article 680.26(C) has added a new twist for bonding the pool water. An intentional bond of a minimum conductive surface area of (9 in2) shall be installed in contact with the pool water.
http://www.kempkeredu.com/articles_read.php?id=5
