Wiring
Garage circuit and panel planning
Before a Level 2 charger goes on the wall, the circuit that feeds it has to be planned. A home EV charger is a continuous load that can draw current for hours, so it is wired on its own dedicated branch circuit rather than shared with garage outlets or lighting. The two questions that drive the plan are how much current the charger needs and how much capacity the home's electrical service can spare.
Why a dedicated circuit
A dedicated circuit serves one piece of equipment. For EV charging this matters because the load is sustained, and code rules in Canada treat continuous loads conservatively. Sharing the circuit with other devices would risk nuisance breaker trips and unsafe loading.
Matching breaker and conductor to the charger
Each charger is rated for a maximum current. The breaker and the conductors are then selected to suit that rating, with the continuous-load margin that the Canadian Electrical Code requires. As a rough illustration of how ratings step up together:
| Charger rated current | General circuit class |
|---|---|
| Lower amperage units | Smaller dedicated circuit |
| Mid amperage units | Mid-size dedicated circuit |
| Higher amperage units | Larger dedicated circuit, often hardwired |
Conductor and breaker sizing is set by code and by the specific equipment. The values for a given install should come from the product instructions and a licensed electrician, not from a generic chart.
Reading available panel capacity
An EV circuit is added to an existing service that already feeds heating, appliances, and lighting. Whether the panel can take another large circuit depends on the service size and the existing load. Older homes with smaller services sometimes cannot add a high-amperage charger without further work.
The load calculation
A load calculation estimates the home's demand and checks whether there is room for the new circuit. This is a standard part of planning a charger install and is the basis for deciding the amperage you can realistically support.
Options when capacity is tight
- Choosing a lower-amperage charger that fits within the available capacity.
- Using a charger with adjustable current settings to stay within limits.
- Considering load management equipment that shares capacity between large loads.
- In some cases, a service upgrade, which is a larger project.
Routing in the garage
Where the panel sits relative to the parking spot affects the conductor run and how it is protected. Runs through finished walls, along exposed surfaces, or outdoors each have their own methods and materials. Confirming the charge-port side of the vehicle early helps place the charger so the cable reaches without stretching.
Public sources
The Canadian Electrical Code is published by CSA Group; an overview is available at csagroup.org. General consumer information on home EV charging from Natural Resources Canada is at natural-resources.canada.ca.