The May 2005 Code Applications column contained information on a major change in Article 680 for the 2005 National Electrical Code (NEC) concerning the construction requirements of fiberglass pools, vinyl-lined pools and concrete pools containing epoxy-coated rebar.
Realizing the ramification this major change has had on certain aspects of the swimming pool industry, Panel 17 has processed a Tentative Interim Amendment (TIA) and submitted it to the National Fire Protection Association's (NFPA) Standards Council. The TIA, approved by the Standards Council in its meeting in July 2005, effectively revises Section 680.26 and its requirement for an equipotential bonding grid to cover the contour of all fiberglass, vinyl-lined, epoxy-coated rebar pools and to extend three feet horizontally under the concrete pool decking.
To understand the revision process, one must first study the requirements for processing a TIA in the NFPA Rules and Regulations Governing Committee Projects. The Standards Council only processes a TIA after the standards council secretary and the panel chair have reviewed the particular issue in question within the document and have agreed that the amendment appears to be of an emergency nature. The NEC Technical Correlating Committee and panel involved in the change must also concur.
Determining the emergency nature of a proposed amendment fits within one of six factors. The first factor is where the document contains an error or omission that was overlooked during the normal revision process.
The second is where the existing document contains a conflict within the document or with another NFPA document. The third is where the proposed TIA intends to correct a previously unknown existing hazard, and the fourth is where the TIA would lessen a recognized known hazard or improve a dangerous condition or situation.
The fifth factor is where the proposed TIA recognizes an advance in the art of safeguarding property and life by providing an alternative method not already in current use or available to the public.
Finally, the sixth factor is when by correcting a circumstance in the original 2005 NEC text has resulted in an adverse impact on a product or method overlooked in the original revision process. This is the factor that fits the current situation.
The change in Section 680.26(C) requiring an equipotential bonding grid for the contour of the pool was originally intended for concrete pools using epoxy-coated rebar and not meant for fiberglass and vinyl-lined pools.
Since this entire industry was adversely impacted without adequate technical substantiation, the TIA has been issued to provide temporary relief and will automatically be processed as a proposal for the 2008 NEC.
The new TIA reads: “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 bonding grid shall conform to the contours of the pool and shall extend within or 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:
“Exception: The equipotential bonding grid shall not be required to be installed under the bottom of or vertically along the walls of vinyl lined polymer wall, fiberglass composite, or other pools constructed of non-conductive materials.
“Any metal parts of the pool, including metal structural supports, shall be bonded in accordance with 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 material.
“(1) Structural Reinforcing Steel. The structural reinforcing steel of a concrete pool or deck where the reinforcing rods are bonded together by the usual steel tie wires or the equivalent. 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 AWG solid copper conductor. Connection shall be per 680.26(D).”
The exception in the TIA exempts the requirement for the bonding grid under or vertically along the walls of vinyl-lined, fiberglass or other pools constructed of nonconductive materials but still require the bonding grid under the concrete walkway within three feet around the pool. EC
ODE is a staff engineering associate at Underwriters Laboratories Inc., in Research Triangle Park, N.C. He can be reached at 919.549.1726 or at firstname.lastname@example.org.