Licensed electrical contractors safely install underground wiring


Ontario Electrical Safety Code (NOEC) allows the underground electrical wiring of a building or property to be directly buried or installed in a cable tray. Photos courtesy of the Electric Safety Authority (ESA)

By Patrick Falzon, C. Tech.
Redoing part of a project because it doesn’t follow the correct code can be frustrating due to cost overruns and project delays. In Ontario, many people outside of the electrical industry are unaware that a Licensed Electrical Contractor (LEC) – a company licensed by the Electrical Safety Authority (ESA) to perform electrical work for hire. – is responsible for the safe installation of conduits / conduits for the purpose of housing the electrical wiring.

From the excavation of the trench to the final electrical inspection by the ESA, an LEC must adhere to the Ontario Electrical Safety Code (NOEC) and the Electricity Licensing Regulations. Most importantly, compliance with these regulations ensures a safe and compliant installation. Requirements may differ by province, so each Provincial Authority Having Jurisdiction (AHJ) should be referenced.

Electrical equipment
NOEC allows underground electrical wiring, such as polyvinyl chloride (PVC) conduit, leading to a building or property to be directly buried or installed in a cable tray. The code defines a conduit as an electrical tube into which conductors are intended to be pulled; it defines a cable tray as any channel designed to contain wires or cables.

Conduit approved for underground installations can be buried directly or encapsulated with poured concrete to provide mechanical protection. NOEC contains detailed installation layout drawings for the conduit / conduit, which includes the associated spacing and depth requirements.

The current carrying capacity of the electrical conductors of the cables (that is to say permissible current) is determined by selecting the configuration diagram, as well as the corresponding permissible current tables prescribed in NOEC. Any change in configuration, including depth, spacing, and number of cable trays / conduits, affects the current rating of the cables. If the installation does not conform to the installation configuration, a detailed technical intensity report will be submitted to determine the allowable amperage of the installed cable, which can become costly and delay the energization of the site.

Conduit approved for underground installations can be buried directly or encapsulated with poured concrete to provide mechanical protection.
Conduit approved for underground installations can be buried directly or encapsulated with poured concrete to provide mechanical protection.

Responsibility for installation
The LEC — meeting the requirements of the Licensing Regulation O. Reg 570/05—The person responsible for the installation must ensure that it complies with all NOEC requirements and all other applicable laws. This means that the LEC in office is required to submit an inspection request (that is to say permit) with the ESA for electrical work, including the installation of conduit (s) or cable tray and associated wiring being installed beyond the property demarcation point. This is defined as the connection point at which the responsibility of the electricity utility ends.

When a trench is created for the purpose of installing conduit to house electrical wiring, it is considered electrical work. However, there have been instances where a LEC has been called in a project after the excavation of the trench and / or the installation of the underground conduit. In fact, before digging the trench, the LEC is required to submit an inspection request to the ESA. Excavation with the appropriate permits in place against the possibility of having to re-dig a facility that does not adhere to NOEC and / or Licensing Regulations.1

An ESA inspector has the authority to inspect all features of this electrical work, including making sure the trench is of an appropriate depth. The LEC applying for the permit may be asked to demonstrate the appropriate trench depth in accordance with NOEC. (It is also important to ask for locations before any excavation by contacting One call from Ontario or a local electric utility.)

By following the Ontario Electrical Safety Code, electricity licenses, and the Ontario One Call regulations described in this article, project teams can ensure underground wiring is installed in a timely, compliant, and safe manner. Architects and building designers should always refer to the NOEC and One Call for specific regulations that apply to a project.

Patrick Falzon, C.Tech., Is a codes specialist for the Codes and Standards department of the Electrical Safety Authority (ESA). He can be reached at [email protected]

Remarks
1 For special regulations, Section 2-004 Inspection, of the Electricity Act must be referenced.

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Patricia D. Rutt