Clearance requirements for pool installations near overhead and underground wiring

by Sally Bouorm | April 1, 2014 3:11 pm

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By Tatjana Dinic

Electrical safety around swimming pools is critical. Overhead power lines as well as underground wiring represent a shock hazard when in close proximity to swimming pools.

The Canadian Electrical Code (CEC)[2] has specific requirements in Section 68, Pools, tubs, and spas, intended to provide enhanced electric-shock protection in these aquatic environments by means of bonding and ground fault circuit interrupter (GFCI) protection.

In the December 2013 issue of Pool & Spa Marketing, pool bonding and GFCI protection were discussed as a means of providing protection to people. This article will focus on clearance requirements between pools and overhead power lines and underground wiring as another means of achieving a safe swimming pool installation environment.

Keep in mind the rules in Section 68 of the CEC regarding clearance requirements between swimming pools and overhead power lines or underground wiring are applicable to wires owned by consumers or local distribution companies (LDCs).

Before reviewing clearance requirements, however, it is important to note Rule 68-002 of the CEC defines a pool as permanently installed and storable swimming pools; hydromassage bathtubs; spas and hot tubs; wading pools; baptismal pools; decorative pools; and splash pads. Therefore, all clearance requirements for overhead or underground wiring are also applicable to hot tubs and splash pads.

Overhead wiring

Clearance requirements between pools and overhead power lines are required to minimize the possibility that a person in or near the swimming pool might come into contact with overhead conductors.

Overhead power lines may not have an insulated covering; this means any conductive object (i.e., pool skimmer or ladder) which makes contact with these lines will become energized and can cause lethal electrical shocks to the person coming in contact with them. For instance, skimmers are often used for pool maintenance and are typically mounted on a long, aluminum handle and can be easily lifted into the air. If the clearance between the pool and any overhead power lines is insufficient, contact between the skimmer’s handle and power lines could be deadly to the user (e.g. a 3-m handle plus the height of the person using the equipment).

Primary distribution and transmission power lines (above 750 V) are typically non-insulated, bare conductors and carry high-voltage power. Secondary distribution power lines (below 750 V) may be insulated and carry low-voltage power. However, the insulation of these conductors may deteriorate over time due to harsh environmental conditions, such as snow, ice, and scorching heat. As a result, the conductors may become frayed or have cracked insulation. Further, some secondary distribution power lines only contain a weather covering, which does not have any insulating value; therefore, it is always the safest assumption to consider all power lines as non-insulated.

Best case scenario

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Ideally, there should be no wiring above a pool or the surrounding deck. In fact, CEC Rule 68-054 prevents pools from being located under overhead wiring. However, locating a pool below overhead conductors is sometimes unavoidable. For example, on a building lot with limited area or a lot where the overhead lines are already in place.

In these circumstances, Rule 68-054 provides some specific exemptions to the type of wiring that are permitted to be located over a pool provided that certain clearances have been met and are maintained. This rule requires the following:

• Communication antenna distribution conductors and power lines (neutral supported cable type) 750 V and below are permitted above the pool and elevated surfaces associated with the pool, or above the adjacent area, provided there is a clearance of at least 5 m (16.4 ft) measured from the outer edge of the pool or from other elevated surfaces associated with the pool.
• All other power lines, operating at not more than 50 kV, are permitted above the pool and elevated surfaces associated with the pool, or above the adjacent area, provided there is a clearance of at least 7.5 m (24.6 ft) measured from the outer edge of the pool or from other elevated surfaces associated with the pool.

The specified clearance requirements stated above are applicable to the pool and other associated elevated surfaces, such as a diving structure, slide, swings, observation stand, tower, or platform, or above the adjacent area extending 5 m (16.4 ft) horizontally from the pool edge.

Figure 1 (above), located in the Appendix B note of Rule 68-054, illustrates the minimum clearances for conductors over swimming pools. No conductors would be permitted under any circumstances in the area under Line 1. In the area above Line 1, insulated communication conductors and neutral supported cables operating at 750 V or less are permitted. Any other conductors operating at not more than 50 kV are permitted above the area outlined by Line 2. Clearances shown beyond 5 m (16.4 ft) from the pool edge are found in Rule 12-304 and Table 34.

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When considering code requirements, it is important to factor in clearance not only for the pool, but also for any adjacent area or structure, e.g. sheds, decks or fences extending 5 m (16.4 ft) horizontally from the pool edge. In the picture here, the clearance requirements specified by Rule 68-054 are not satisfied. The conductors are within 5 m (16.4 ft) from the pool and the clearance from the wires to the edge of the pool is less than 5 m (16.4 ft).

It is important to understand the clearance requirements specified in Rule 68-054 are harmonized with Canadian Standards Association (CSA) standard C22.3 No. 1, Overhead systems. Many LDCs reference this standard as part of their electrical safety distribution regulation.

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.

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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. [8]

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[9].

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