How much does it cost to run power to a garage?

The cost depends first on whether the garage is attached or detached.

An attached garage is usually the lower-cost version because the wiring can often be run from the house panel through finished or unfinished interior space, while a detached garage adds exterior feeder work, trenching, burial-rated wiring or conduit, and weatherproof transitions.

For an attached garage, the price usually maps to the type of circuit being added:

Those are Canadian-dollar budgeting numbers, not a blind promise. The actual run power to garage cost changes quickly if the panel is full, the route crosses finished ceilings, the garage needs a subpanel, or the driveway and landscaping affect trenching.

A detached garage is different from running one cable across a basement ceiling. We need to look at the path from the house to the garage, where the feeder exits the building, whether the trench crosses asphalt, interlock, tree roots, gas lines, drainage, or a walkway, and how the cable will be protected where it comes above grade. That is why detached garage power is normally quoted in writing after a site visit rather than priced from a photo.

If you only need one new receptacle in an attached garage, read our guide to adding an outlet cost. If the job is a new circuit from the panel, the closest service match is dedicated circuit installation.

A garage feeder, subpanel, or new branch circuit needs an ESA notification where required.

In Ontario, new garage wiring is not just a handyman job; new feeders, subpanels, and branch circuits normally require an ESA notification and inspection when the work is electrical installation work under the Ontario Electrical Safety Code.

For a garage project, the ESA inspection is not cosmetic. The inspector is looking at whether the installation is safe and code-compliant, including items such as:

• Correct breaker size for the conductor used
• Proper cable or conduit type for the garage and any exterior or underground section
• Required GFCI protection for garage receptacles where applicable
• Weatherproof boxes, covers, connectors, and fittings in damp or exterior locations
• Correct neutral isolation and bonding in a subpanel
• Grounding and bonding requirements for a detached structure where applicable
• Burial depth, mechanical protection, and marking of underground wiring where applicable
• Clear panel labelling and safe working space at the panel or subpanel

Attached garages often need a circuit for receptacles, lighting, a garage door opener, a freezer, a workbench, or future equipment. Detached garages often need a feeder instead of just a branch circuit, especially if you want lights, receptacles, exterior lighting, a heater, or EV charging later.

The key difference is control and capacity. With a branch circuit, everything in the garage depends on that one breaker. With a subpanel, the garage can have separate breakers for lighting, receptacles, exterior outlets, and future equipment. That is cleaner, easier to troubleshoot, and better for future upgrades, but it must be sized and installed properly.

City Power Electrical Services is an ECRA/ESA licensed electrical contractor, ECRA/ESA #7015314, and we include required ESA steps in written garage power quotes rather than treating inspection as an afterthought.

Check the house panel and utility service before deciding the amperage.

You should not choose a garage circuit size until a licensed electrician checks the existing panel, service capacity, and likely future loads. A garage may look simple, but the load calculation can be the deciding factor.

Before we recommend a 20A circuit, 50A circuit, or subpanel, we look at:

• Whether the home has 100A, 200A, or another service size
• The number of open spaces in the panel and whether tandem breakers are allowed in that panel
• Existing large loads such as electric range, dryer, air conditioning, heat pump, hot tub, EV charger, or electric heat
• Whether the main breaker and service conductors can support the added load
• Whether the garage use is occasional, continuous, or likely to grow
• Whether the local utility equipment and meter base limit the service upgrade path

This matters most when the garage is being made EV-ready. A 20A receptacle circuit is a very different load from a 40A EV charger circuit. If the house is already tight on capacity, a load-management device or panel upgrade may be part of the discussion before anyone promises a large garage feeder.

For EV planning, compare the garage wiring scope with Tesla charger installation cost. A Level 2 charger often drives the circuit size, panel capacity review, and garage layout. If you are planning for a welder, compressor, kiln, or large heater, that should be disclosed at the estimate stage too. It is cheaper to size the feeder correctly once than to trench twice.

Utility involvement is usually not needed for a simple branch circuit. It may become relevant if the load calculation points to a service upgrade, meter base change, or a larger main service. In Toronto and the GTA, the utility could be Toronto Hydro, Alectra, Elexicon, Hydro One, Oshawa Power, Oakville Hydro, Burlington Hydro, or another local distributor depending on the address.

Detached garage trenching is the biggest unknown.

For a detached garage, the trench route is often what separates a small electrical project from a larger construction job. The electrical design may be straightforward, but the path between buildings can add labour, coordination, and restoration.

A site visit checks details that cannot be priced accurately from a phone call:

• Distance from the house panel to the garage
• Whether the feeder can leave near the panel or must cross finished rooms first
• Soil, rock, tree roots, retaining walls, concrete, asphalt, or interlock in the route
• Whether the trench crosses a driveway, walkway, garden, or shared property area
• Location of gas, water, drainage, irrigation, and communication lines
• Where the feeder can enter the garage without damage or exposed cable
• Whether a grounding electrode is required at the detached building
• Whether the garage needs interior lighting, exterior lighting, receptacles, or a subpanel

Underground electrical work also has sequencing. Before digging, buried services need to be located. The trench must suit the wiring method, the cable or conduit must be protected, and the installation may need to remain visible for inspection before backfilling. If the trench is backfilled too early or the wrong material is used, it can create an ESA defect and rework.

This is also where detached garage power differs from a small shed. A shed might only need a light and one receptacle. A garage often has door openers, vehicle charging, tools, exterior lighting, security cameras, freezers, and future workshop use. For comparison, see running power to a shed, but do not assume the same feeder size or trench details apply.

EV-ready planning is worth deciding before the trench is dug.

If you might charge an EV in the garage later, say so before the quote is built. EV-ready planning can affect the feeder size, subpanel size, conduit route, breaker space, and whether the garage should get a larger capacity path now.

The practical question is not “Can we get power to the garage?” The better question is “What do you want the garage to support five years from now?” A single 20A receptacle may be enough for lights and a door opener. It is not the same plan as a future Level 2 EV charger, heater, compressor, and exterior outlets.

Common garage planning choices include:

• Basic attached garage: one 20A circuit for receptacles and light-duty loads.
• Workshop garage: multiple receptacles, better lighting, and possibly a 30A–50A circuit for equipment.
• EV-ready garage: feeder or circuit planned around charger location, panel capacity, and vehicle parking position.
• Detached multi-use garage: subpanel, lighting circuit, receptacle circuits, exterior GFCI receptacles, and spare capacity where the load calculation allows.

If the garage will have a dryer-style outlet, welder outlet, or EV charger, do not choose the receptacle type first and the circuit second. The breaker, conductor, receptacle, equipment rating, and load calculation all have to match. For another example of a high-load garage-adjacent circuit, see our guide to hot tub circuit cost, where GFCI protection, disconnect placement, and outdoor wiring conditions also shape the job.

A good garage quote should list the amperage, wiring method, panel work, trenching assumptions, ESA notification, inspection plan, and cleanup. If any of those are missing, the number may not be comparing the full job.