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#3564 - 01/03/07 05:48 AM
Bonding of Pool Water
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Secretary
   
Registered: 10/05/04
Posts: 1622
Loc: City of North Port
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Well, it looks like the CMP panel has reversed its opinion on the proposal requiring the bonding of the water in a pool. If you recall, this same group brought this issue to the table during the 2005 cycle but with very little substantiation at that time. It looks like they are going to get this one in the 2008... Here's the original rejected proposal: ___________________________________________________________ 17-122 Log #1894 NEC-P17 Final Action: Reject (680.26(C) (New) ) ____________________________________________________________ Submitter: Frank C. Lambert, Georgia Tech/NEETRAC / Rep. National Electric Energy Testing, Research, & Applications Center Recommendation: Insert a new Section 680.26(C) as follows: 680.26(C) Pool Water. An intentional bond of a minimum conductive surface area of 5806 mm 2 (9 in 2 ) shall be installed in contact with the pool water. This bond shall be permitted to consist of parts that are required to be bonded in 680.26(B). Renumber the present sections sequentially from (C) to (D), (D) to (E), and (E) to (F). Substantiation: Bonding of metal parts in and around a swimming pool to an equipotential bonding grid is extensively covered in 680.26. The intent of this bonding is to equalize the voltages between the pool water and the deck including any attached metal structures or parts. 680.26 has been effective in mitigating stray voltage problems, especially in the case of fiberglass swimming pools or pools with insulated liners. 680.26 describes various metal parts and equipment that require bonding with an equipotential bonding grid. In describing these metal parts, it is assumed that one or more of the parts are in contact with the pool water. This may not always be the case. Some pools do not have any bonded metal parts in contact with the water. In such a case, intentional bonding of the water is necessary to equalize the water-to-deck voltages. Presently, 680.26 does not have a provision for intentional bonding of the pool water. Panel Meeting Action: Reject Panel Statement: The submitter has not provided adequate substantiation. There are issues such as conductivity of water, changes with water temperature, current flow, size of conductors, etc. that need to be addressed. Number Eligible to Vote: 11 Ballot Results: Affirmative: 9 Negative: 2 Explanation of Negative: HIRSCH, B.: The testing done by the National Electric Energy Testing, Research and Applications Center (NEETRAC) clearly substantiates that the potential for shock hazard is increased in pools where the pool water is not bonded via metal parts in the pool. Results of this testing were reported to Panel 17 at the proposal meeting in January of 2006. Based on this testing, EEI supports the adoption of this proposal and as such is voting negative to the panel’s action. At the proposal meeting, Panel 17 indicated they had additional questions that needed to be answered before supporting this proposal. The panel statement, however, did little to document those concerns. Just as the submitter needs to provide compelling substantiation for a code change, the code panel has the responsibility to provide a justifiable technical basis to reject well supported proposals. JHONSON, D.: I agree with the Submitter’s substantiation, and, in addition, the substantiation of the NEETRAC testing results reported to Code-Making Panel 17 at the ROP meeting in January of 2006. I have provided additional relevant pool test results from a project supervised by the university of Newcastle, Australia and sponsored by Energy Australia. This reports a potential shock hazard when conditions exist effectively bridging the isolation of the pool water provided by an insulated pool shell. This issue should be revisited. Note: Supporting Material is available for review at NFPA headquarters. ____________________________________________________________ Here's the reversal at the comment stage: 17-99 Log #1190 NEC-P17 (680.26(C) (New) Final Action: Accept Submitter: Neil F. LaBrake, Jr. , National Grid Rep. Edison Electric Insitute-Electric Light & Power Group Comment on Proposal No: 17- 122 Recommendation: Accept Proposal 17- 122. Substantiation: Testing done by a National Laboratory (NEETRAC) clearly substantiates that the potential for shock hazard is present in pools where the pool water is not bonded via metal parts in the pool. With this knowledge and confirmation of a potential shock hazard , CMP- 17 must address the issue. NEETRAC, in its proposal , recommended a solution for bonding pool water. The proposed solution was tested and worked successfully. While the proposed solution may not be the only solution , it meets the NEC criteria of providing minimum protection for the public. Panel Meeting Action: Accept
17-98 Log #802 NEC-P17 (680.26(C) (New) Final Action: Accept Submitter: Frank C. Lambert, Georgia TechlNEETRAC Comment on Proposal No: 17- 122 Recommendation: Proposal 17- 122 should have been adopted in its entirety. Substantiation: Extensive testing clearly substantiates that the potential for voltage gradient is present in pools where the pool water is not bonded via metal parts in the pool. With this knowledge and confirmation of a voltage gradient hazard , the CMP must address the issue. Test results, handed out at the Proposal Meeting, show that the presence of a touch potential exists in all areas of the pool and that the proposed solution for bonding pool water will essentially reduce that potential to zero. While the proposed solution may not be the only solution , it meets the NEC criteria of providing minimum protection for the public. The test report in its entirety has been submitted to this Comment for further review by the Panel Members. Typically, pool water is considered electrically conductive due to dissolved chemicals. Although the conductivity will vary with the temperature, the change in conductivity for all practical purposes is not a factor in the application of a proposed solution. Again, the proposed solution meets the NEC criteria of providing minimum protection for the public and should be viewed as a protection measure compared to having no protection. In the proposed solution , the size of bonding conductor is not specified. This is in line with several Bonded Parts described in 680.26(B). In 680.26(B)(1), (B)(2), (B)(3), and (B)(5), use of a minimum of #8 AWG size wire is implied as specified in 680.26(B)(4) and 680.26(C). In the stray voltage field, ground currents are rarely determined due to measurement difficulties and inaccuracies. On the other hand , resulting voltage gradients (stray voltages), however, are very easy to measure and can be directly used to analyze stray voltage problems and their mitigation. As evidenced by the test report, the proposed solution is based on such stray voltage measurements around a swimming pool. Note: Supporting material is available for review at NFPA Headquarters. Panel Meeting Action: Accept
_________________________
Bryan P. Holland, MCP
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Registered: 02/02/07
Posts: 0
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