The requirements for swimming pool bonding were revised…again.

680.26(B)(2) Perimeter Surfaces. An equipotential bonding grid must extend 3 ft horizontally beyond the inside walls of a pool, outdoor spa, or outdoor hot tub, including unpaved, paved, and poured concrete surfaces. Perimeter surfaces less than 3 ft that are separated by a permanent wall or building 5 ft in height or more require an equipotential bonding grid on the pool side of the permanent wall or building.

The bonding grid must comply with (a) or (b) and be attached to the conductive pool reinforcing steel at a minimum of four points uniformly spaced around the perimeter of the walls of a pool, outdoor spa, or outdoor hot tub.

(a) Structural Reinforcing Steel. Unencapsulated structural reinforcing steel in concrete shells secured together by steel tie wires [680.26(B)(1)(a)].

(b) Alternative Copper Conductor Grid. Where the structural reinforcing steel isn’t available (or is encapsulated in a nonconductive compound, such as epoxy), an equipotential bonding grid meeting all of the following requirements must be installed (click here to see Fig. 19):

(1) The bonding grid must be 8 AWG solid copper, arranged in the manner described in 680.26(B)(1)(b)(3).

(2) The bonding grid must follow the contour of the perimeter surface extending 3 ft horizontally beyond the inside walls of pool.

(3) Listed splicing devices must be used.

(4) The grid must be secured in or under the deck or unpaved surface within 4 in. to 6 in. of the underside of the deck.

(3) Metallic Components. Metallic parts of the pool, outdoor spa, or outdoor hot tub structure must be bonded to the equipotential grid.

(4) Underwater Metal Forming Shells. Metal forming shells and mounting brackets for luminaires and speakers must be bonded to the equipotential grid.

(5) Metal Fittings. Metal fittings sized 4 in. and larger that penetrate into the pool, outdoor spa, or outdoor hot tub structure, such as ladders and handrails, must be bonded to the equipotential grid.

(6) Electrical Equipment. Metal parts of electrical equipment associated with the pool, outdoor spa, or outdoor hot tub water circulating system, such as water heaters and pump motors and metal parts of pool covers, must be bonded to the equipotential grid.

Ex.: Metal parts of listed double insulation equipment isn’t required to be bonded to the equipotential grid.

(a) Double-Insulated Water-Pump Motors. If a double-insulated water-pump motor is installed, a solid 8 AWG copper conductor from the bonding grid must be provided for a replacement motor.

(b) Pool Water Heaters. Pool water heaters must be grounded and bonded in accordance with equipment instructions.

(7) Fixed Metal Parts. All fixed metal parts must be bonded to the equipotential grid, including but not limited to metal-sheathed cables and raceways, metal piping, metal awnings, metal fences, and metal door and window frames.

Ex. 1: If separated from the pool, outdoor spa, or outdoor hot tub structure by a permanent barrier that prevents contact by a person.

Ex. 2: If located more than 5 ft horizontally of the inside walls of the pool, outdoor spa, or outdoor hot tub structure.

Ex. 3: If located more than 12 ft measured vertically above the maximum water level.

(C) Pool Water. Pool water must have an electrical connection to one or more of the bonded parts described in 680.26(B). If none of the bonded parts is in direct connection with the pool water, the pool water must be in direct contact with an approved corrosion-resistant conductive surface that exposes not less than 9 sq in. of surface area to the pool water at all times, and it must be bonded in accordance with 680.26(B). (click here to see Fig. 20)

Analysis: This section has been revised extensively over the last few Code change cycles, and this one is no exception. Recent revisions have left gaping holes in the requirements not to mention plenty of room for misunderstanding, misinterpretation, and misapplication. The changes in the 2011 edition of the NEC seek to remedy these problems.

The connection of the copper bonding grid discussed in 680.26(B)(1)(b)(1) has been addressed. When nonconductive structural reinforcing steel is used in a pool, a bonding grid of 8 AWG copper conductors is required, but previous editions of the Code didn’t address how to connect the grid to itself. This NEC cycle clarifies that the grid must be bonded together at all points of crossing in the grid, and the bonding means must comply with the connection provisions of 250.8. Also, 680.26(B)((2)(b) was revised, requiring a copper grid instead of the single conductor permitted in 2008. Fortunately, this provision isn’t used often as it would be an incredibly time consuming and expensive solution.

A clarification was also made regarding the bonding of the pool deck. It isn’t uncommon for a pool deck to be less than 3 ft when a wall, fence, or other structure is near the pool. Previous editions of the Code didn’t tell the user how to handle the situations, but now it’s clear that the bonding doesn’t need to extend to the other side of the wall, provided the wall (or fence) is no less than 5 ft in height.

The bonding of nonelectric metal parts has been clarified. Section 680.26(B)(7) has long required that “metal wiring methods and equipment” be bonded to the equipotential grid discussed in this section. One question that often comes up, however, is whether the “equipment” contemplated in this rule applies to only “electrical equipment,” as defined in Art. 100 — or if it’s intended to apply to all equipment, including nonelectrical equipment. This change clarifies that this provision does, in fact, apply to nonelectrical equipment, such as metal fences and similar items.

Lastly, the exception allowing for a permanent barrier separating metal parts has been clarified. A change to the exception makes it clear that such a barrier must prevent a person from contacting metal parts and equipment that aren’t bonded.