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Powerlines and pools: Location is key

By Patrick Falzon

The object does not have to make physical contact with an overhead powerline to cause serious injury or death as electricity can jump (arc) to an object one is holding.
The object does not have to make physical contact with an overhead powerline to cause serious injury or death as electricity can jump (arc) to an object one is holding.

Before deciding on a location to install a pool, installers and homeowners should be aware of the location of overhead and underground powerlines on the property. These powerlines can be owned either by the local distribution company (LDC) to supply power to a home and neighbours or by the customer to supply power to a shed, for example.

The Ontario Electrical Safety Code (OESC) sets the minimum safety requirements for the installation of pools and hot tubs in correlation to overhead and underground wiring, respectively.

Understanding the hazards

Powerlines are categorized into two distribution levels, primary distribution (above 750 V) and secondary distribution (below 750 V). They can be installed either overhead or underground.

Overhead powerlines

Overheard primary distribution powerlines are typically bare conductors whereas secondary distribution powerlines may be insulated. However, the insulation of these conductors may fray or crack over time due to harsh environmental conditions, such as snow, ice, and scorching heat. Also, some secondary lines contain only weather covering, which has no insulating value. Therefore, it is always the safest assumption to consider all powerlines as non-insulated.

Any conductive object (i.e. pool skimmer or ladder) that makes contact with these lines may become energized and can seriously injure or kill people around it. In addition, it is important to understand the object does not have to make physical contact with an overhead powerline to cause serious injury or death as electricity can jump (arc) to an object one is holding.

Meeting the requirements of the OESC for overhead powerlines

Rule 68-054 (1) of the OESC does not permit a pool to be placed under or near overhead powerlines or permit overhead powerlines to be placed over or near a pool. Rule 68-054 (2) goes further to include elevated surfaces associated with the pool such as diving structure, slide, swing, observation stand, tower, or platform extending 5 m (16.5 ft) horizontally from the pool edge.

However, sometimes this is unavoidable due to limited space on the property. Consequently, under certain conditions, some exemptions in the rule will permit a pool to be placed under or near overhead powerlines.

Rule 68-054 (3) permits insulated communication conductors, and powerlines not exceeding 750 V above the pool and elevated surfaces associated with the pool, or above the adjacent area extending horizontally from the pool edge. This is provided to allow a clearance of at least 5 m measured from the outer edge of the pool or from other elevated surfaces associated with the pool.

Rule 68-054 (4) permits other conductors and powerlines operating at not more than 50,000 V above the pool and elevated surfaces associated with the pool, or above the adjacent area extending horizontally from the pool edge. This is provided to allow a clearance of at least 7.5 m (24.7 ft) measured from the outer edge of the pool or from other elevated surfaces associated with the pool.

Diagram 1: Clearance for overhead lines on over and around pools. *Note: Some LDC’s do not permit a pool to be placed under their overhead wires regardless of whether the pool meets Diagram 1.
Diagram 1: Clearance for overhead lines on over and around pools. Note: Some LDC’s do not permit a pool to be placed under their overhead wires regardless of whether the pool meets Diagram 1.

Diagram 1 (above) clearly illustrates the above requirements. 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 50,000 V are permitted above the area outlined by ‘Line 2.’

Picture 1: Installation which did not meet the clearance requirements of the code.
Picture 1: Installation which did not meet the clearance requirements of the code.

The photo labelled ‘Picture 1’  (at right) shows an installation which did not meet the requirements of the OESC. The overhead powerlines had to be relocated for the pool installation to meet the clearance requirements of the OESC.

Underground powerlines

Installation of underground cables can be direct buried or in a conduit.

Meeting the requirements of the code for underground powerlines

Rule 68-056 of the OESC requires horizontal separation between the inside walls of the pool and underground powerlines. The horizontal separation shall not be less than that shown in Table 61 (below) of the OESC. This does not apply to the underground bonding conductors or wiring associated with the pool that is protected by a Class A ground fault circuit interrupter (GFCI).

Table 61 of the Ontario Electrical Safety Code (OESC): Minimum buried cable horizontal separations from pools.
Table 61 of the Ontario Electrical Safety Code (OESC): Minimum buried cable horizontal separations from pools. Notes: 1. Voltages are phase-to-phase. 2. This Table is derived from CEA 266 D 991. 3. The separation from non-conducting ducts is measured from the nearest edge of the duct to the inside wall of the pool.

Proactive approach

The following steps can help builders, or a client be safe from electrical hazards and avoid costly and timely relocation of the overhead or underground powerlines.

Perform a visual

Determine if there are existing overhead wires located in the vicinity of the proposed pool location. Determining if underground powerlines are present can be difficult. Look for signs such as a meter base located at the rear of the house or power supplied to an existing shed on the property, for example.

Contact the LDC well in advance

Contact the LDC to determine if they own any underground powerlines on or around the property. If overhead powerlines are present, they will confirm ownership of the powerlines. If they do own the powerlines, they will need to verify if the location of the proposed pool will meet overhead clearance requirements of their code.

Call before you dig

Contact Ontario One Call (www.on1call.com) to locate all utility owned underground infrastructure. Note: Customer-owned underground infrastructure is not located through Ontario One Call. Private locates will be required to locate customer-owned underground infrastructure.

Patrick Falzon is a powerline safety specialist with the Electrical Safety Authority (ESA). The ESA’s role is to enhance public electrical safety in Ontario. As an administrative authority acting on behalf of the Government of Ontario, ESA is responsible for administering specific regulations related to the Ontario Electrical Safety Code (OESC), the licensing of electrical contractors and master electricians, electricity distribution system safety, and electrical product safety. ESA works extensively with stakeholders throughout the province on education, training, and promotion to foster electrical safety. For more information, visit www.esasafe.com.

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