How to Bury Electrical Wire Safely in the Yard

Running power to a garden shed, hot tub, garage, EV charging station, or landscape lighting fixture usually means burying cable across a portion of your Toronto or GTA yard. Do it right and it lasts for decades. Do it wrong and you get corroded cable, dead circuits, and — in the worst case — a live conductor a few inches under grass where a homeowner is going to hit it with a shovel one spring. This guide covers what the Ontario code and utility rules actually require for buried electrical wire, cable and conduit choices, and when to call a licensed contractor.

How to bury electrical wire safely in the yard

To bury electrical wire safely in Ontario, use a cable or conduit rated for direct burial (or install a burial-rated conductor inside PVC conduit), trench to the depth the Ontario Electrical Safety Code specifies for the voltage and cable type you are using, add warning tape or physical protection where required, and file an ESA notification with an ECRA/ESA-licensed contractor for any circuit above simple homeowner exemption scope. Indoor cable (NMD90 / Romex) is not allowed underground — use the right cable for the job. See can you bury indoor electrical wire underground for the specifics.

Locate before you dig

Before any trenching in Ontario, call Ontario One Call (dial 1-800-400-2255 or the shortcode where available) to have public utilities marked. Free service, required by law, and it stops you from cutting your neighbour’s gas line while installing your shed circuit. Private locates (for buried irrigation, invisible fence, private hydro to a coach house, or septic) may also be needed and are usually separate.

Cable choice: what to use, what to avoid

• NMWU (Non-Metallic Wet Underground) or UF (Underground Feeder in NEC contexts): approved for direct burial without conduit. Common for residential runs to sheds, landscape lighting, and outdoor receptacles. Full breakdown at Romex, THHN, and UF wire.
• RW90 XLPE conductors in PVC conduit: the standard for larger residential and commercial feeders (subpanel to shed, service to detached garage).
• Rigid metal conduit (RMC) with THWN conductors: heavier duty, higher mechanical protection.

Not allowed underground:

• NMD90 (indoor Romex) unprotected in soil.
• Standard household extension cords.
• Landscape-lighting low-voltage cable used for line voltage.
• Any cable without the burial rating printed on the sheath.

Trench depth requirements

Minimum burial depth in Ontario depends on the cable type, voltage, and whether it is protected by conduit. General guidance for typical residential 120/240V circuits:

• Direct-burial cable (NMWU or equivalent), no conduit: generally 600 mm (about 24 inches) minimum cover.
• Cable in PVC conduit: generally 450 mm (about 18 inches) minimum cover.
• Cable in rigid metal conduit: shallower minimum in some cases, per the OESC.
• Under a driveway or roadway: deeper cover typically required.
• GFCI-protected 120V circuits at 20 amps or less: some reduced-cover exceptions apply.

Always confirm the specific depth for your project with an ESA-licensed contractor — the code has multiple tables and the wrong cover depth will fail inspection. Full breakdown coming in our companion post on trench depth.

Trenching, warning tape, and protection

1. Mark the trench route with paint or chalk.
2. Have Ontario One Call locates completed and marked in the ground.
3. Trench to the specified depth. Machine trenching for long runs; hand-dig near utilities.
4. Lay a bed of clean sand or fine soil in the trench base to protect cable or conduit.
5. Install cable or conduit in the trench, keeping bends within listed radius.
6. Cover with 150 mm of fine soil, then install code-required warning tape above the cable if applicable.
7. Backfill the remainder in lifts, compacting as you go.
8. Restore surface (sod, gravel, concrete).

Warning tape (typically bright yellow or red plastic labelled “Caution Buried Electric Line”) is required by the OESC in specific configurations and is a good idea in all of them. It gives future diggers 6–12 inches of warning before they hit the cable itself.

GFCI protection is often required

Any circuit terminating at an outdoor receptacle, hot tub, pool, or landscape lighting fixture typically requires GFCI protection under the current OESC. See are outdoor outlets required to be GFCI protected. GFCI can be installed at the panel with a GFCI breaker or at the first receptacle in the run.

Permits, notifications, and DIY limits

Ontario’s homeowner exemption lets a homeowner do their own electrical work on their own single-family primary residence, including outdoor circuits, but every new outdoor circuit typically requires an ESA notification. Anything supplying a shed, detached garage, hot tub, or pool is definitely notification territory. If you are not eligible for the homeowner exemption (rental, condo, second property), the work must be done by an ECRA/ESA-licensed contractor.

Consequences of skipping the permit at what happens if I do electrical work without a permit.

Common Ontario projects that need buried wire

• Detached garage subpanel. Usually a 60-amp or 100-amp feeder from the house to the garage. See how to run power to a detached garage.
• Garden shed with lights and a 15-amp outlet. See how to wire a shed for electricity.
• Hot tub 40- or 50-amp GFCI circuit. See how to wire a hot tub yourself safely.
• Landscape lighting. Line-voltage runs to transformers or fixtures.
• Backyard EV charger for a detached garage. High-amperage feeder plus subpanel.

Expert tip from our ESA-licensed electricians

In our GTA field data, the single most common buried-cable failure is not depth or cable choice — it is the transition point where the buried run meets the above-ground service head or the exterior wall of the building. Water and freeze-thaw cycles concentrate exactly at that transition, and if the fitting is not weatherproof (proper LB or condulet, gasketed cover, drip loop), water tracks down the conduit and shows up inside the panel two years later. When you plan a buried run, spend the extra ten minutes on the two ends. Cheap on install day, expensive on the day the panel starts rusting.

Related reading from ezsmart.ca

• Can You Bury Indoor Electrical Wire Underground?
• How to Run Power to a Detached Garage
• How to Wire a Shed for Electricity
• What Is the Difference Between Romex, THHN, and UF Wire?
• Are Outdoor Outlets Required to Be GFCI Protected?

Contact us

Planning a buried electrical run in a Toronto or GTA yard? Call ezsmart at 416-838-9006 or use our contact page. An ESA-licensed electrician will size the cable, trench safely, and file the notification.