Bonding of Metal Near Swimming Pools and Spas

Metal Parts Requiring Bonding – all Pools and Outdoor Spas and Hot Tubs
1. Connect together (bond) most metal near or associated with all indoor and outdoor swimming pools and outdoor spas, and hot tubs. References to pools in the following list include spas and hot tubs built as part of a swimming pool or installed as free-standing units. Components requiring bonding include:
(a) All metal parts of conductive pool shells including reinforcing steel and any other metal parts of the pool structure. Concrete and masonry pool shells are conductive. Vinyl and fiberglass pool shells are not conductive. Pool shell reinforcing bars with standard wire ties are a bonding grid when the ties are wound tight. You may use a copper wire bonding grid instead of reinforcing bars or if the reinforcing bars do not exist. Refer to the IRC for details about copper wire bonding grids.
(b) Conductive surfaces within (≤) 3 feet from the inside edge of a pool. Conductive surfaces in42 : Electrical Requirements for Pools, Spas, Whirlpool Tubs, Fountains 467
clude unpaved areas, earth, concrete, brick, masonry, and similar surfaces. Bond the conductive surface using reinforcing steel or a copper wire bonding grid. Connect the surface bonding grid to the pool shell bonding grid at at least (≥) 4 equally spaced points around the pool.
(c) Metal shells and mounting brackets of no-niche lights, except for listed low voltage lights.
(d) Metal parts and fi tt ings inside or att ached to the pool structure, except for isolated parts not more than (≤) 4 inches long that penetrate into the structure not more than (≤) 1 inch.
(e) Metal parts of electrical equipment associated with the water circulation system and any motorized pool covers. This includes pump motors, chlorinators and other sanitation equipment, water heating equipment, and motors for pool, spa, and hot tub covers.
(f) Metal within (≤) 5 feet horizontally from the inside edge of the pool and within (≤) 12 feet vertically from the maximum water level and from the top of any diving structure, viewing stand, and similar structures. Metal includes metal conduit and tubing, junction boxes, enclosures, lights, fans, pipes, awnings, fences, and door and window frames.                                                                                                                                                                                                                                                                                                                             (g) Water. Provide a conductive area of at least (≥) 9 square inches. Any combination of conductive surfaces from items (a) through (f) that are in conductive contact with the water satisfy this provision for bonding the water. Water bonding is usually an issue only in vinyl and fiberglass pools because these pools are nonconductive.
(h) Metal cases of water heating equipment. Follow manufacturer’s instructions for grounding and bonding water heaters rated at more than (>) 50 amps.
2. You do not need to bond the surface identified in (b) and metal parts identified in (f) within 3 feet from the pool’s inside edge if the area is separated from the pool by a permanent wall more than (>) 5 feet high or by a building.
3. You do not need to bond the surface identified in (b) within 3 feet from the inside edge of a listed self-contained indoor spa or hot tub that is installed on a finished floor.
4. You do not need to bond pool shell reinforcing steel if it is covered by a nonconductive material.
5. You do not need to bond any metal hoops or similar components used to secure wood surrounding spas and hot tubs.

Metal Parts Requiring Bonding – Indoor Spas and Hot Tubs
1. Connect together (bond) most metal near or associated with all indoor spas, and hot tubs. This includes:
(a) Metal parts and fittings inside or attached to the spa or hot tub.
(b) Metal parts of electrical equipment associated with the water circulation system. This includes pump motors and chemical injectors. This does not include pump motors that are part of a listed self-contained spa or hot tub.
(c) Metal wiring methods and plumbing piping within (≤) 5 feet horizontally from the inside edge of the spa or hot tub. This includes metal conduit, tubing, junction boxes, enclosures, and plumbing pipes. This does not include metal separated by a wall, fl oor, or other permanent barrier.
(d) Metal within (≤) 5 feet from the inside edge of the spa or hot tub. This does not include metal separated by a wall, floor, or other permanent barrier. This does not include metal air and water jets, drain fitting, and similar parts if not connected to metal piping, and this does not include towel bars, mirror frames, and similar non-electrical equipment.
(e) Electrical devices and controls that are not associated with the spa or hot tub and are less than (<) 5 feet from the inside edge of the spa or hot tub.

Bonding Method
1. Install a solid copper bonding wire at least (≥) #8 AWG or install rigid brass or other corrosionresistant metal conduit that connects all parts requiring bonding. Metal parts mean isolated pieces of metal that are not otherwise electrically connected. Example: the steel reinforcing shell of an in-ground concrete swimming pool is one metal part because all of the bars should be connected to each other by wire ties.
2. Use heat welds or approved pressure clamps made from stainless steel, brass, or copper to connect the bonding wire to bonded metal parts. You may use machine screws secured with a nut or threaded machine screws. Screws should engage the fastening device with at least two threads. Do not use solder or sheet metal screws.
3. You do not need to run the bonding wire to the electrical service equipment, panelboard, or grounding electrode.

Bonding Discussion
The purpose of bonding is to connect metal parts together so that if one part becomes electrically energized its voltage will not be different from any nearby metal part. If metal parts are at different voltages, a person touching one part could become the electrical path to ground if he touches a nearby metal part. Bonding and grounding are not the same. Bonding connects metal parts to each other. Grounding connects electrical equipment to an earth grounding point. Note that some metal parts, such as pool circulation equipment, must be both grounded and bonded. In this case, the grounding wire is usually contained in the electrical wires serving the equipment and the bonding wire is usually connected to the metal exterior of the equipment.