Engineering Technical Bulletin

Underground Electrical Infrastructure Clearances

Clearances around underground electrical infrastructure as per Burlington Hydro's specifications and standards must be met by planners, architects, developers / contractors, municipalities, and property owners and managers. Electrical workers must be able to safely access equipment to operate, maintain or replace it, see Figure 1. The property owner will be responsible for any costs related to removing an obstruction, or if power restoration is delayed due to the obstruction.

Figure 1: Clearances to Pad Mounted Equipment

Clearances around pad mounted electrical equipment mitigate risks associated with working space and hazards related to the ground grid. 3 meters (10 feet) on all sides of pad mounted equipment must be free of any structures, obstructions, or plantings.

Excavating & Digging

Extreme caution should be used when digging near marked underground infrastructure or electrical poles (including guy wires and the ground grid). Contact with a sharp shovel or excavation equipment could easily damage electrical infrastructure and could result in injuries or fatalities due to contact with electrical current.

See the Electrical Safety Authority’s Guideline for Excavating in the Proximity of Underground Distribution Lines and contact Burlington Hydro for guidance before excavation in the proximity of electrical infrastructure.

Figure 2: Collaspible Zones

add alt — Collapsible Zones demonstrate the potential for cave ins, infrastructure damage and fatalities due to excavation that breach allowable clearances. The ground around hydro poles with and without guy wires can have unique vulnerabilities. Always respect the No Dig Zone.

Other Underground Utilities

Burlington Hydro and all other underground infrastructure stakeholders including telecommunications, water, wastewater, and gas facilities must meet the clearances for underground electrical infrastructure as per CSA C22.3 No.7 Underground Systems.

In order to meet these requirements, coordination of all facilities within the proximity of other underground equipment is essential.

Municipalities & Property Owners

Above ground obstructions or hiding the electrical equipment is not permitted. Municipalities and property owners must be aware of the clearances for the safety of its assets in proximity to underground electrical infrastructure, including but not limited to:

Municipalities: bus shelters, traffic signs
Property Owners: decks or patio blocks, retaining walls, pool equipment, hot tubs, storage sheds, metallic objects like mail-boxes, flag posts, outdoor patio seating (temporary and permanent)

Locates

If you are planning on digging, drilling, blasting, augering, or driving stakes or fence posts into the ground, Ontario law requires that you call or click Ontario One Call before you dig to arrange a FREE underground locate.

Call Ontario One Call, 24-hours-a-day, 7-days-a-week at 1-800-400-2255
Or submit an online request on the Ontario One Call website

Call or submit your request at least five working days prior to digging to schedule this service. Additional notice may be required during the busy spring season.

The various utilities will mark the location of buried underground infrastructure so the dig can be done safely.

Contractors: As a contractor doing digging, you are responsible for obtaining a locate from Ontario One Call for your jobs such as excavating for an addition, new building, sidewalks, or driveways, or repairing buried infrastructure.

Property Owners: Any time you dig on or near your property to plant a tree, landscape, install a fence, deck, or driveway, or repair buried infrastructure (pools, heated driveways, irrigation and sprinkler systems), etc., you must request a locate from Ontario One Call.