Equipotential bonding for pools and spas

This information bulletin alerts swimming pool and spa installers and electrical contractors to the requirements of Australian Standards concerning the installation of electrical equipment bonding earths on pool equipment and in pool zones as per AS/NZS 3000:2018 Wiring Rules.

AS/NZS 3000:2018 Wiring Rules

Clauses 5.6.2.6 Swimming and spa pools and 6.3.3 Protection against electric shock

The following information refers to Clauses 5.6.2.6 Swimming and spa pools and 6.3.3 Protection against electric shock.

Where electrical equipment is in contact with pool water, failure of electrical insulation may result in a hazardous voltage appearing across or through the pool water. A very low voltage is sufficient to present a serious hazard to persons immersed in the water.

Protective measures may include:

• location of the electrical equipment at a distance from the pool with all plumbing connections being made of non-conductive materials, or
• metal grids or barriers inserted in any plumbing connections between the electrical equipment and pool and connected to the equipotential bonding system, or
• use of an RCD (Safety Switch) rated at 30 mA to protect circuits supplying Class I equipment. (Equipment with earthed conductive parts, e.g. metallic pool pump motors.

Items that must be equipotential bonded to earth

Regardless of the measures taken above the following items must be equipotential bonded to earth:

• The exposed conductive part of any electrical equipment in the classified pool zones. (Refer to AS/NZS 3000 for the defined zones).
• Any exposed conductive parts of electrical equipment that are not separated from live parts by double insulation and that are in contact with the pool water, including water in the circulation or filtering system (e.g. metallic pool pump motors).

Bonding shall be extended to further items

Where either of the items described above exist, the bonding shall be extended to the following additional items:

• Any fixed external conductive parts of the pool structure, including the reinforcing metal of the pool shell and deck
• Any conductive fittings within or attached to the pool structure, such as pool ladders and diving boards
• Any fixed conductive material within arm’s reach of the pool edge, such as conductive fences, lamp posts and pipe work.

The bonding conductor shall be terminated or connected by any of the means permitted in AS/NZS 3000. In addition, where the connection may be subjected to the deteriorating effect of the pool water, it shall be covered with, or encapsulated in, a suitable compound.

An equipotential bonding conductor shall be connected between the bonded parts and the earthing conductor associated with each circuit supplying the pool or spa, or the earthing bar at the switchboard at which the circuit originates.

Conductive tie-wires used during construction of reinforced concrete pools are considered to be an adequate electrical bond between the conductive reinforcing components. Provided that the reinforcement is satisfactorily electrically connected together, one point of connection of the bonding conductor to the reinforcement is satisfactory where bonding is required.