I would agree with Cavie in that “There is no requirement that every square be tied at every corner.” The 2005 NEC informs that: “The usual steel tie wires shall be considered suitable for bonding the reinforcing steel together, and welding or special clamping shall not be required. How the steel is tied with said tie wires (other than tight…) and how often is not addressed in the NEC and (I believe, as Cavie does) this is a structural issue not relevant to the NEC.
Technically, (it appears to me) if each reinforcing bar is connected to another reinforcing bar with only a single usual steel tie wire made up tight, it has met the requirements of the 05 NEC… (I seriously doubt, but don’t really know, either… that this would be adequate from a structural standpoint…) This appears to be adequate from the 05 NEC’s standpoint.
I would have to disagree with Cavie in his statement of: “It is required that the EC hit the grid in at least 4 places around the perimeter of the pool with the #8.”
… (it just doesn’t seem to say that , to me…)
While I will agree that this is what the inspector will be looking for, the 2005 NEC seems to permit much less for compliance.
My understanding is:
2005 NEC Section 680.26(C) informs that a single #8 solid (or rigid metal conduit of brass or other identified corrosion-resistant metal conduit) is all that is necessary to bond the items noted in Sections 680.26(B) to the grid. The grid itself can be comprised of the elements in 680.26(C)(1) or (C)(2) or (C)(3).
The structural reinforcing steel of a concrete pool, once bonded together with the usual steel tie wires, is one option permitted to comprise the equipotential bonding grid (in the 05 NEC) and the pool shell can be bonded to the deck with structural reinforcing steel tied together with the usual steel tie wires (or other permissible methods…).
Once the grid is established, each list item in Sections 680.26(B)(1) through (B)(5) need only be connected to the grid with a single #8 solid [connections accomplished to meet requirements in Section 680.26(D)]. A ladder's mounting brackets could be bonded to the grid in one corner and the pool equipment could be bonded to the grid at the opposite corner. They are bonded together through the grid and the #8 does not need to: “hit the grid in at least 4 places around the perimeter of the pool”.
…While I would certainly do more equipotential bonding than this (and my experience is that most do considerably more…), it seems to me this is all that is required in the 05 NEC.
If I am misinterpreting this, please let me know. This is my understanding…
I am just trying to be accurate… for accuracies’ sake.
…,Personally I believe you cannot do enough equipotential bonding in and around pools. This is a safety requirement to "reduce" voltage gradients and is expected to accomplish the performance requirements of Section 680.26(A) for the life of the pool…
… That being said, I believe it is extremely helpful to understand what the minimum requirements are so one can perform said bonding to a much higher level… In addition, each installation brings with it unique situations which seem to require additional review of what those minimum requirements are…
mweaver