Expert Knowledge & Advice
Commonly Asked Questions
Can You Install an EV Charger on a 100-Amp Electrical Service?
One of the most common questions we receive from electric-vehicle owners is:
“Can I install a Level 2 EV charger if my house only has a 100-amp electrical service?”
In many cases, the answer is yes.
Having a 100-amp service does not automatically mean that your home needs to be upgraded to 200 amps before an EV charger can be installed. The right solution depends on your home’s existing electrical load, the charging speed you need and how the charger will be controlled.
The First Step Is an Electrical Load Assessment
Before recommending a charger, we look at the electrical equipment already supplied by the home, including:
- Electric heating
- Air conditioning
- Electric water heating
- Stoves and dryers
- Hot tubs, pools or other large loads
- The size and condition of the electrical panel
- The output required from the EV charger
Ontario’s Electrical Safety Authority allows service capacity to be evaluated using prescribed load calculations and, under appropriate circumstances, demonstrated historical demand. This helps determine whether the existing service can safely accommodate EV charging or whether another solution is required.
Option 1: Install the Charger at a Lower Amperage
Not every driver needs the maximum output available from their charger.
A properly configured charger operating at 24 or 32 amps may still provide more than enough overnight charging for someone’s normal daily driving. The charger, breaker and wiring must all be selected and configured as one complete system.
Certain fixed-in-place EV chargers can be commissioned below their maximum rating. Under current Ontario requirements, the setting must be properly restricted and labelled—it is not simply a matter of the homeowner changing the amperage whenever they choose.
Option 2: Use an Energy Management System
An energy management system monitors the amount of electricity being used by the home and controls the EV charger accordingly.
When electrical demand is low, the vehicle can charge normally. When larger household loads are operating, the system can temporarily reduce or pause charging to prevent the home from exceeding its available capacity.
Where an approved energy management system monitors the consumer service and controls the EV charger, the EV charging load may not need to be included in the calculated service load in the usual manner. This can make it possible to install an EV charger without immediately upgrading a 100-amp service.
Option 3: Upgrade the Service to 200 Amps
Sometimes a service upgrade is still the most practical long-term solution.
A 200-amp service may be recommended when the home already has several large electrical loads or when the homeowner is planning future additions such as:
- A second electric vehicle
- Electric heating or a heat pump
- A hot tub or pool
- An induction range
- A finished basement or home addition
- Battery storage or other electrification projects
The goal should not be to sell every homeowner a service upgrade. It should be to assess the home properly and recommend the solution that makes sense for its current and future electrical needs.
Plug-In Charger or Hardwired Charger?
Level 2 chargers can be either hardwired directly into the electrical system or connected through a receptacle such as a NEMA 14-50.
For cord-connected EV chargers, the ESA requires the receptacle to be protected by a 50-amp overcurrent device.
When installing a plug-in charger, we recommend using a heavy-duty receptacle specifically designed for EV charging. EV charging places a substantial load on the receptacle for several hours at a time. Manufacturers of EV-grade receptacles design them for this purpose, while ordinary 50-amp receptacles are specifically identified as unsuitable for EV charging.
In the installation featured in our video, we also used #6 copper armoured cable, commonly referred to as BX. The metal armour provides a durable wiring method for the exposed garage installation. Conductor size and wiring method are not identical for every charger; they must be selected based on the charger output, circuit rating, installation conditions, distance and manufacturer’s instructions.
Permits and Licensed Installation
EV chargers are large, continuous electrical loads. They should not be treated like ordinary household appliances.
In Ontario, EV-charger installations require an electrical notification or permit, and electrical work performed for hire must be completed by a Licensed Electrical Contractor. The charger must also carry an approved Canadian certification mark.
Do You Need to Upgrade Your 100-Amp Service?
Possibly—but not necessarily.
GO Electrical can assess your existing service, review the available charging options and explain whether your home is best suited for:
- A standard Level 2 installation
- A reduced-amperage charger
- An energy management system
- A 100-to-200-amp service upgrade
We provide EV-charger installations throughout York and Durham Region. Send us a picture of your electrical panel and a brief description of where you park, and we can help you determine the most practical next step.
