Clearance requirements for pool installations near overhead and underground wiring

Underground wiring

A person in a swimming pool can receive an electric shock and be rendered immobile by a voltage gradient in the water. The level of electrical current necessary to cause immobilization may not cause death from electrical shock, but it could lead to accidental drowning. The reason for the voltage gradient in the water may be underground wiring that is too close to the pool. This may include conductors supplying power to a residence (including telephone or cable TV), supplying power to a garage, outdoor equipment, a panel installed in the backyard shed or power to the neighbourhood.

There may be a leakage current flowing between or from underground conductors to surroundings. These leakage currents values are not normally high enough to trip an over-current device protecting those conductors. They may find a path through the pool or its equipment and cause a shock or a ‘tingling’ sensation to bathers. In this case, Rule 68-056 (see Figure 2: Table 61) provides the following clearance requirements:

• The horizontal separation between the inside walls of a pool and underground conductors for wiring not associated with a pool should not be less than that shown in Table 61;
• GFCI protection is required on any underground circuit located closer than the minimum separation distances specified in Table 61; and
• The spacing requirements in Table 61 are not applicable to bonding conductors. 

It is important to understand the clearance requirements specified in Rule 68-056 are harmonized with CSA standard C22.3 No. 7, Underground systems. Many LDCs reference this standard as part of their electrical safety distribution regulation.

A popular question

The following question is often asked about clearance requirements between pools and underground installations as well as applicable wiring methods for underground electrical systems:

With an above-ground pool, what is the minimum distance between underground, non-metal conduits such as poly(vinyl chloride) (PVC) conduit or cable, and the pool?

Answer

Rule 68-056 applies to above-ground, inground and all other types of swimming pools listed in Rule 68-000(2). If the PVC raceway/cable is supplying equipment directly related to the pool (e.g. pump, lighting, etc.) and the circuit is GFCI protected, there is no minimum separation required.

However, if a PVC raceway/cable is supplying non-pool related equipment, it must be kept separated from the inside walls of the pool by the distances specified in Table 61.

Tatjana Dinic, P.Eng., is a code engineer with the Electrical Safety Authority (ESA) in Ontario, which establishes safety standards for the installation of electrical equipment in the province and is in charge of enforcing the Ontario Electrical Safety Code (OESC). She can be reached via e-mail at tatjana.dinic@electricalsafety.on.ca.