Previous to the 2005 NEC the Mass Electric Code recognized an issue regarding epoxy encapsulated re-bar in poured pools. This state required under such condition that a # 8 Solid Copper be ran through the re-bar at a distance of 15 feet. Comment 17-171 on Proposal 17-124 (680.27 ) originally suggested a 3 foot spacing this was submitted by a Mass Code Advisory Panel Member and was accepted in principle. The language that found it's way to the text as you know is 12". Also Proposal 17-120 (680.26(B) (6)) was accepted at the proposal stage and apparently rejected in comment # 17-167. This proposal specifically stated to bond the pool water. The panel accepted it 10 to 1.
The whole drift that I get from reading the proposals is that which was submitted in proposal 17-120. It was submitted by a representative of a power company citing gradient voltages from their system finding it's way into the pool water (Liability). “Ground Potential Rise”. The proposal discussed non conductive liners (not that much different from a fiber glass liner, do you own a glass hull boat?) preventing the pool water from coming in contact with the bonding grid. .
The fact is if you read the proposals and the comments it is difficult to determine where the CMP deviated from the original proposal when it spelled out the need to bond in 680.26 (B) and the alternate means described in 680.26 (C).
Personally I'm in NO BIG hurry to bond the pool water, but I do know that glass hulls of boats transmit and hold water (osmosis). I don't see the difference with a glass pool.
The NEC needs to make up it's mind. concerning these installations. The only body that can interpret the NEC is the Code Panel. The local jurisdictions (Gov’t Bodies) can amend the NEC as is done in Massachusetts.
The language in the book does not provide a great amount of wiggle room.
Charlie Palmieri
