Service Upgrade?
A common question: Do I need to upgrade my electrical service/panel to install a Level 2 EVSE (EV "charger")?
Not necessarily. Many people are able to install EVSEs on 100 amp services, for example. There are two areas to address:
1. Panel space
Your panel needs to have physical space for installing a double-pole breaker (240V). This varies by panel model, but generally requires two ‘spaces’.
But even if your panel is currently physically full, there may be options to make space. This could include combining existing circuits onto tandem breakers (for example, two 15A circuits in a single space). Or installing a sub panel.
2. Service capacity
This relates to the current (amp) rating of the wires, panel, and breaker coming into your home.
a) The first thing to try is determining the calculated load for your service, according to Section 8 of the Canadian Electrical Code – particularly Rule 8-200 for single dwellings (do not use US based calculators since they are different). This involves a basic load according to the area of your home and adding your significant loads based on demand factors in the Code. In general, loads 1500W or less don’t count, as they are covered under the basic load. Loads like electric range, electric heat, electric water heater, hot tub, EV charging, etc. are typical loads considered, but not necessarily taken at 100%.
Once you know your existing calculated load, the difference between that and your service capacity is what is available for adding an EVSE.
b) If the calculated load doesn’t leave enough capacity, there is the alternative of using your historical demand (demonstrated load). This may differ by province, but generally provinces like Ontario and BC allow you to get the historical hourly usage for the past 12 months from the utility, and use that along with the instructions to determine the available capacity for additional loads like an EVSE.
c) If that still doesn’t allow enough available capacity for your proposed EVSE, maybe you could use an EVSE set to a lower current (amp) rating. Many people don’t actually need to charge at 40A or 48A, but would do fine with 16A, 24A, or 32A, for example. Some EVSEs that come with higher ratings can be adjusted (derated) to a lower maximum current in ways that meet approval for inspections.
d) EVEMS (Electric Vehicle Energy Management System), also referred to as load management. I recommend avoiding EVEMS if possible due to added complication (expense, and added failure points - higher risk of EV not getting charged when you need it, although that risk is minimal), and limiting to EVSE choices (many reward programs don't have EVEMS options). But this is an option where the EVEMS system monitors your electrical service, and will slow down or turn off your EV charging if the current at the service is getting too high.
Additional Information/References
For Ontario (ESA bulletins)
https://esasafe.com/assets/files/esasafe/pdf/Electrical_Safety_Products/Bulletins/08-03-16.pdf
- Section 1)a) for example calculated load
- Section 4) for using demonstrated load
https://esasafe.com/assets/files/esasafe/pdf/Electrical_Safety_Products/Bulletins/86-01-7.pdf
- Section 4) for adjustable EVSE (derating)
- Section 1) for EVEMS
For British Columbia (TSBC)
- Using historical demand
- Derating EVSE to lower current
- EVEMS