How to Wire a Shed for Electricity?

Backyard sheds in Ontario go from lawnmower storage to real workshops, art studios, gyms, and even short-term rental spaces. Adding electricity turns a shed from a seasonal item to a year-round space. The install is straightforward when planned right — a small subpanel, a buried feeder, and code-compliant fixtures inside. This guide walks GTA homeowners through how to wire a shed for electricity, what the Ontario Electrical Safety Code requires, and where the boundary sits between homeowner-permitted work and licensed-contractor territory.

Short answer: subpanel fed from the house via buried NMWU or conduit

Direct answer: install a small subpanel (30-60 A) in the shed, feed it from the house’s main panel via NMWU direct-buried cable or NMD-90 in buried PVC conduit, drive a ground rod at the shed for the local bond, and wire branch circuits inside the shed for lighting and receptacles. Load calc, ESA notification, and inspection.

Sizing the shed’s feeder

• 30 A subpanel: lighting + 2 receptacles + small workshop tools. 10/3 NMWU or 10 AWG in conduit.
• 60 A subpanel: lighting + multiple receptacles + tablesaw or welder + heater. 6/3 NMWU.
• 100 A subpanel: full workshop or rental unit. 3/3 NMWU.

For most residential sheds, 30 or 60 A is adequate. Only serious workshop use warrants 100 A. Our post on subpanels covers sizing decisions.

The install: step by step

1. Load calculation. Contractor verifies the main panel can support the new feeder.
2. ESA notification filed before any physical work.
3. Ontario One Call for utility locates. Free service, mandatory before digging.
4. Trench dug. 900 mm depth for direct-buried NMWU; 450 mm for PVC conduit.
5. Cable pulled from house to shed. Feeder cable secured every 1.4 m if exposed.
6. House-side termination. Feeder breaker installed in the main panel; feeder conductors landed on breaker and neutral/ground bars.
7. Shed subpanel mounted. Interior wall of shed, or exterior weatherproof enclosure.
8. Shed-side termination. Feeder conductors landed on subpanel’s main lugs or main breaker. Neutral and ground bars separated (not bonded).
9. Ground rod driven. 2.4 m (8 ft) rod at the shed, bonded to the subpanel ground bar with 6 AWG copper.
10. Branch circuits. Lighting on one circuit, receptacles on another. GFCI protection on all shed receptacles per OESC Section 26.
11. ESA inspection. Sign-off before energization.

Ground rod requirement

Direct answer: detached structures like sheds and garages require a local grounding electrode (ground rod). Section 10 of the Ontario Electrical Safety Code specifies the ground rod at the detached structure be bonded to the subpanel ground bar. This provides local fault current paths that do not rely solely on the feeder bond.

Missing the ground rod is one of the top writeups on shed and detached-structure inspections. Do not skip it.

Fixtures and receptacles inside the shed

• Lighting: LED shop lights (2-4 fixtures for a typical shed). Wall switch near the door.
• Receptacles: at least 2, positioned for workshop tools. All GFCI-protected under OESC Section 26.
• Outdoor receptacle: weatherproof-rated with in-use cover if on the shed exterior.
• Exhaust fan or heater: optional, sized to the subpanel’s remaining capacity.
• Smoke alarm if the shed is habitable: Ontario Building Code requires interconnected smoke alarms in dwelling units.

Cost expectations in the GTA

• Short-run 30 A shed install: $1,800-3,000.
• Longer 30 A run (over 20 m): $2,500-4,000.
• 60 A shed install: $3,000-5,000.
• 100 A workshop-quality install: $4,500-7,000.
• Add-on if main panel needs upgrading: +$3,800-5,500.

DIY portions homeowners can handle

• Digging the trench (before the contractor arrives).
• Building the shed itself if not already present.
• Painting or finishing the interior surfaces.
• Coordinating the ESA notification paperwork if under a Homeowner Wiring Notification.

Common mistakes on DIY shed wiring

• Extension cord from house to shed. Never a permanent solution. Fire risk, code violation.
• Bonded neutral at shed subpanel. Same violation as detached garages — shocks and inspection failure.
• Missing ground rod. Required for detached structures.
• Non-GFCI receptacles. All shed receptacles need GFCI.
• Undersized feeder. Cheap cable that limits future use.
• NMD-90 buried directly. Not permitted — use NMWU or conduit. Our post on burying indoor wire covers this.

Expert tip from our ESA-licensed electricians

In our experience wiring sheds across GTA back yards — particularly workshop and hobby-space sheds in Vaughan, Richmond Hill, and Etobicoke — the single detail that saves customers the most money and future callbacks is oversizing the feeder for future use. A 30 A subpanel today with 6/3 NMWU (60 A capacity) in the ground costs $200 more than the minimum 10/3 for 30 A. Three years later when the customer decides to add welding equipment or a heat pump, the feeder is already sized for it — the upgrade is just swapping the subpanel and breakers. Homeowners who install minimum-spec feeders re-trench the yard within 5 years. Our post on detached garage power covers the larger-scale version.

Related reading from ezsmart.ca

• Power to detached garage
• What is a subpanel?
• Bury indoor wire?
• Landscape lighting transformers
• Add a new circuit

Frequently Asked Questions

Do I need a permit to wire a shed?

Yes. Any new circuit to an outbuilding requires an ESA notification filed by a licensed contractor.

What cable is used for a buried shed run?

NMWU direct-burial cable or RW90 conductors in PVC conduit are the residential standards.

How deep does the trench need to be?

Typically 600 mm for direct burial or 450 mm with PVC conduit for a residential 120V run.

Is GFCI required at the shed?

Yes for outdoor and detached-structure receptacles under the current OESC.

Do I need a subpanel in the shed?

For more than a couple of circuits or heavier loads, yes. A licensed contractor sizes it correctly.

Contact us

Wiring a shed in the GTA and want an ESA-certified electrician to size and install the feeder? Call us at 416-838-9006 or visit our contact page — we will get back to you the same day.

Amir Azimipour

Electrician Since 2008 Journeyman Electrician Designated Master Electrician at EZSMART Corp