The requirements for bonding and grounding permanently installed indoor and outdoor swimming pools are provided in Article 680 Swimming Pools, Fountains and Similar Installations" of the 2005 Edition of the National Electrical Code (NEC). All of the bonded parts in or around swimming pools must be attached to an equipotential bonding grid. This grid must extend 3 (0.91 m) beyond the inside surface of the pool under concrete, stone or other paved walking surfaces.