What does it cost to run underground power from my house to a detached garage in Ottawa?

Running underground power from your house to a detached garage in Ottawa costs between $2,000 and $6,000 depending on the distance, the amperage you need, soil conditions, and what is between your house and garage that the trench needs to navigate around.

For a straightforward run of 15 to 20 metres with 60-amp service, most Ottawa electricians quote $2,000 to $3,500 all in. A 100-amp service over the same distance runs $3,000 to $4,500 because the heavier gauge copper wire is significantly more expensive per metre. Once you get beyond 25 metres, costs climb quickly due to both wire costs and the additional trenching labour, and runs over 30 metres typically land in the $4,000 to $6,000 range.

The Ontario Electrical Safety Code requires underground electrical conduit to be buried at a minimum depth of 600 millimetres below finished grade. Your electrician will use approved PVC electrical conduit, typically schedule 40 or schedule 80, with the wire pulled through after the conduit is laid and backfilled. At each end, the conduit rises out of the ground and connects to a weatherproof junction point or directly into the panel.

Trenching is a major cost factor and depends heavily on your Ottawa property. A clear, straight run across a lawn is the easiest scenario and can often be done with a walk-behind trencher in a few hours. Complications that increase cost include crossing a paved driveway, which requires saw-cutting and patching at $500 to $1,500 extra. Landscaping restoration for gardens, retaining walls, or established plantings that need to be carefully worked around adds cost. Hitting the Canadian Shield rock that sits close to the surface in parts of Ottawa west end, Kanata, and Stittsville can require a rock saw or hammer drill and adds $500 to $2,000. You also need to call Ontario One Call before any digging to have underground utilities marked at no charge, and your electrician should arrange this as part of the project.

The wire itself is the other big cost driver. For a 60-amp underground run, you need 6 AWG copper conductors, and for 100 amps you need 3 AWG or larger depending on the distance. Copper prices fluctuate, but as of early 2026 a 100-amp rated underground cable costs roughly $8 to $15 per metre. On a 25-metre run, the wire alone can be $400 to $750.

Permit and Inspection Requirements

This work requires an ESA permit because you are extending your home's electrical system to another structure. The ESA inspector will check the trench depth before backfill, the conduit connections at both ends, the wire sizing for the distance and load, and the sub-panel installation in the garage. Your electrician coordinates the inspection timing, and you should budget two to three weeks for the full process from permit to final sign-off.

One alternative some homeowners ask about is running an overhead service wire from the house to the garage on a mast. While this is technically possible and cheaper at $1,200 to $2,500, most Ottawa homeowners prefer underground because it looks cleaner, avoids clearance requirements over driveways, and is not vulnerable to ice storm damage, which Ottawa knows all too well.

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Looking for experienced contractors? The Ottawa Construction Network connects Ottawa homeowners with qualified professionals:

• Justyn Rook Contracting
• RenoMotion Inc.
• Dreamwood Construction & Renovations
• Ottawa Garage Doors & Openers
• ARTEXPRO Tile & Finishes