680.26 Equipotential Bonding.
(A) Performance. The equipotential bonding required by
this section shall be installed to reduce voltage gradients in
the pool area.
(B) Bonded Parts. The parts specified in 680.26(B)(1)
through (B)(7) shall be bonded together using solid copper
conductors, insulated covered, or bare, not smaller than
8 AWG or with rigid metal conduit of brass or other identified
corrosion-resistant metal. Connections to bonded
parts shall be made in accordance with 250.8. An 8 AWG or
larger solid copper bonding conductor provided to reduce
voltage gradients in the pool area shall not be required to be
extended or attached to remote panelboards, service equipment,
or electrodes.
(1) Conductive Pool Shells. Bonding to conductive pool
shells shall be provided as specified in 680.26(B)(1)(a) or
(B)(1)(b). Poured concrete, pneumatically applied or sprayed
concrete, and concrete block with painted or plastered coatings
shall all be considered conductive materials due to water
permeability and porosity. Vinyl liners and fiberglass composite
shells shall be considered to be nonconductive materials.
(a) Structural Reinforcing Steel. Unencapsulated structural
reinforcing steel shall be bonded together by steel tie
wires or the equivalent. Where structural reinforcing steel is
encapsulated in a nonconductive compound, a copper conductor
grid shall be installed in accordance with 680.26(B)(1)(b).
(b) Copper Conductor Grid. A copper conductor grid
shall be provided and shall comply with (b)(1) through (b)(4).
(1) Be constructed of minimum 8 AWG bare solid copper
conductors bonded to each other at all points of crossing.
The bonding shall be in accordance with 250.8 or
other approved means.
(2) Conform to the contour of the pool
(3) Be arranged in a 300-mm (12-in.) by 300-mm (12-in.)
network of conductors in a uniformly spaced perpendicular
grid pattern with a tolerance of 100 mm (4 in.)
(4) Be secured within or under the pool no more than
150 mm (6 in.) from the outer contour of the pool shell
(2) Perimeter Surfaces. The perimeter surface shall extend
for 1 m (3 ft) horizontally beyond the inside walls of
the pool and shall include unpaved surfaces, as well as
poured concrete surfaces and other types of paving. Perimeter
surfaces less than 1 m (3 ft) separated by a permanent
wall or building 1.5 m (5 ft) in height or more shall require
equipotential bonding on the pool side of the permanent
wall or building. Bonding to perimeter surfaces shall be
provided as specified in 680.26(B)(2)(a) or (2)(b) and shall
be attached to the pool reinforcing steel or copper conductor
grid at a minimum of four (4) points uniformly spaced
around the perimeter of the pool. For nonconductive pool
shells, bonding at four points shall not be required.
(a) Structural Reinforcing Steel. Structural reinforcing
steel shall be bonded in accordance with 680.26(B)(1)(a).
(b) Alternate Means. Where structural reinforcing steel
is not available or is encapsulated in a nonconductive compound,
a copper conductor(s) shall be utilized where the
following requirements are met:
(1) At least one minimum 8 AWG bare solid copper conductor
shall be provided.
(2) The conductors shall follow the contour of the perimeter
surface.
(3) Only listed splices shall be permitted.
(4) The required conductor shall be 450 mm to 600 mm
(18 in. to 24 in.) from the inside walls of the pool.
(5) The required conductor shall be secured within or under
the perimeter surface 100 mm to 150 mm (4 in. to
6 in.) below the subgrade.