If your Toronto home has a 100 amp electrical service, you may be wondering whether you can install a Level 2 EV charger without upgrading to 200 amps.
Yes, a 100 amp service can be enough for a home EV charger in some Toronto homes. Having a 100 amp service does not automatically mean an EV charger requires a service upgrade. What matters is the home’s existing electrical demand, the charging load being added, the charger’s configured output, and whether an approved Energy Management System can be used if capacity is limited. Ontario’s Electrical Safety Authority provides methods for determining whether an existing dwelling service needs to be upgraded when EV charging equipment is added. For information about assessing your home and planning an EV charger installation in Toronto, visit https://xboct.ca/ev-charger-installation/.
Toronto Hydro similarly advises homeowners that adding an EV charger might require an electrical service upgrade, but not always. It recommends having a Licensed Electrical Contractor assess the home’s existing capacity and charging options before deciding whether an upgrade is necessary.
So if someone tells you that every 100 amp Toronto home needs to become a 200 amp home before installing a Level 2 charger, that is too broad a rule.
The correct answer depends on the house.
Can You Install a Level 2 EV Charger on a 100 Amp Service?
Potentially, yes.
A 100 amp electrical service can support EV charging when the home’s existing electrical demand leaves sufficient capacity for the proposed charger or when an appropriate load-management solution is incorporated into the installation.
Level 2 charging operates at 240 volts and generally places a much larger load on a home’s electrical system than Level 1 charging. Toronto Hydro notes that Level 2 chargers may require electrical upgrades depending on the home’s existing capacity.
The key word is may.
Two Toronto houses can both have 100 amp services and receive completely different answers about EV charging.
For example, one house may use natural gas for:
- space heating;
- water heating;
- cooking; and
- other major household loads.
Another 100 amp home may have:
- electric heating;
- an electric range;
- an electric water heater;
- a clothes dryer;
- central air conditioning or a heat pump;
- a hot tub; and
- other significant electrical equipment.
The second property may have much less unused capacity available for an EV charger.
That is why the number printed on the main breaker is only the starting point.
Does a 100 Amp Panel Mean I Only Have 100 Amps Available for New Equipment?
No.
A 100 amp service means the electrical service has a 100 amp rating. It does not mean you have 100 amps sitting unused and available for a new EV charger.
Your home is already using part of that capacity.
Before an EV charger is added, the contractor needs to determine the demand created by the existing electrical loads and then evaluate the additional EV charging load.
Ontario’s EV charging bulletin specifically addresses how a new service rating can be calculated when EVSE is added to an existing dwelling and recognizes demonstrated historical load as one permitted method under the applicable Ontario Electrical Safety Code rules.
Toronto Hydro also offers a peak-demand tool in its customer portal specifically to help homeowners and Licensed Electrical Contractors determine whether an electrical upgrade may be necessary for new EV charging equipment.
How Do Electricians Determine Whether 100 Amps Is Enough?
The assessment is more involved than simply looking at the main breaker.
A Licensed Electrical Contractor may consider factors including:
Existing Electrical Loads
Major electrical appliances and equipment contribute to the home’s overall electrical demand.
The more significant electrical loads already connected to a 100 amp service, the less flexibility there may be for adding another large load.
Historical Electrical Demand
For an existing dwelling, demonstrated demand may be relevant when determining whether the existing electrical service can accommodate additional EV charging equipment under applicable Ontario rules. ESA’s current EV charging bulletin specifically refers to the demonstrated-load calculation method when determining whether a service upgrade is required.
Toronto Hydro’s peak-demand tool can also show the highest amount of electricity the home has used at one time and is intended to help homeowners and contractors evaluate whether an upgrade is necessary.
The EV Charger’s Maximum Current
Not every Level 2 EV charger draws the same amount of current.
The charging equipment selected—and the output at which it will be installed—can significantly affect whether the existing 100 amp service is practical.
ESA’s current Bulletin 86-1-7 permits certain fixed-in-place EV charging equipment to use approved adjustable amperage settings for maximum circuit-loading purposes when the manufacturer’s instructions and specified restrictions are followed.
Other Planned Electrical Upgrades
Your current situation is not the only consideration.
If you are also planning to electrify other systems in the near future, the long-term answer may be different.
Adding an EV charger today may be practical on 100 amps, but adding an electric heat pump, electric water heater, induction range, second EV charger and other substantial loads later could change the calculation.
How Much Power Does a Home EV Charger Need?
There is no single amperage requirement for every Level 2 home charger.
Level 2 equipment operates at 240 volts, but charging output can vary depending on the charger, vehicle and installation. ESA describes Level 2 charging as having electrical requirements comparable to a large household appliance and notes that these systems require greater voltage and amperage than Level 1 charging.
This distinction matters tremendously in a 100 amp home.
You may not need the highest possible charging rate simply because the charger supports it.
For many EV owners, the more useful question is:
How much charging do I actually need overnight?
If your vehicle remains parked for many hours each night and your typical daily driving is moderate, a lower Level 2 charging rate may still replenish your daily energy use comfortably.
Choosing charging output based on your real driving requirements can sometimes make an installation more practical than designing around the charger’s maximum possible output.
Can I Reduce the EV Charger’s Amperage to Stay on a 100 Amp Service?
With appropriate equipment and installation, this can sometimes be part of the solution.
Some fixed-in-place EV chargers allow the installer to commission the equipment at a lower maximum charging current.
Ontario ESA Bulletin 86-1-7 states that adjustable amperage settings can be used for fixed-in-place equipment for maximum circuit-loading purposes when the manufacturer’s instructions are followed and specific requirements are met, including restrictions on access to the adjustment and appropriate permanent marking when required.
This is important because a charger capable of a high maximum output does not necessarily have to be installed at that maximum output.
For example, if your driving needs can comfortably be met by a lower charging rate, configuring compatible equipment accordingly may reduce the additional demand placed on a 100 amp electrical service.
This decision should be made as part of the electrical design rather than by changing charger settings yourself after installation.
Would Load Management Let Me Keep My 100 Amp Service?
It may.
An Energy Management System, or EMS, can be particularly useful when a home’s existing electrical demand leaves insufficient capacity for an EV charger operating independently.
ESA’s current electrical guidance allows Energy Management Systems to monitor electrical loads and automatically control EV charging equipment. An EMS can connect, disconnect, increase or reduce power to controlled loads based on the system design.
In practical terms, imagine your home is using a large amount of electricity because several major appliances are operating simultaneously.
A properly designed EMS can control the EV charging load so the home does not simply add the charger’s full demand on top of everything else.
When household demand decreases, more capacity can become available for charging.
ESA’s rules also provide specific treatment of EVSE demand where an EMS monitors the consumer’s service and feeders and controls the charger.
For some 100 amp Toronto homes, this can make load management worth evaluating before automatically proceeding with a 200 amp service upgrade.
Is an EV Energy Management System the Same as a Smart Charger?
Not necessarily.
A charger having Wi-Fi, an app, scheduled charging or an adjustable charging setting does not automatically mean it qualifies as the Energy Management System required for electrical load management.
ESA specifically addresses this distinction in its EV charging bulletin. An EVSE cannot simply be treated as an EMS unless it has the features necessary to perform the required energy-management function.
That is an important consideration when purchasing charging equipment.
A consumer-facing feature described as “smart charging” is not necessarily the same thing as an electrical Energy Management System designed to control loads for service-capacity purposes.
When Is a 100 Amp Service More Likely to Be Enough?
Although every home requires its own assessment, retaining a 100 amp service may be more feasible when:
- the home’s existing electrical demand is relatively modest;
- major heating or cooking loads use natural gas rather than electricity;
- only one EV charger is being added;
- the required charging speed is moderate;
- compatible EVSE can be configured to an appropriate output;
- historical demand demonstrates sufficient available capacity; or
- an approved Energy Management System can appropriately control the charging load.
These factors do not guarantee that a particular 100 amp installation will qualify, but they illustrate why service size alone cannot determine the answer. ESA’s guidance requires the additional EVSE demand and applicable load-management arrangements to be considered when evaluating an existing service.
When Might 100 Amp Service Not Be Enough?
A service upgrade becomes more likely when the home already has substantial electrical demand and there is insufficient capacity to accommodate the proposed EV charging system.
Examples of significant electrical loads can include:
- electric resistance heating;
- heat pumps with substantial electrical requirements;
- electric water heating;
- electric ranges and ovens;
- clothes dryers;
- hot tubs;
- pools;
- workshop equipment;
- accessory dwelling units;
- multiple EV chargers; and
- other large electrical loads.
The proposed charging rate matters as well.
A homeowner seeking higher-output charging while operating multiple major electrical systems may encounter capacity limitations more readily than a homeowner whose house has relatively modest electrical demand.
Toronto Hydro advises that an electrical service upgrade may be required when new electrical equipment such as an EV charger increases the home’s electrical demand beyond what the existing service can accommodate.
What If I Plan to Own Two EVs?
Two EVs do not necessarily mean you must immediately upgrade to 200 amp service, but they introduce additional design considerations.
Depending on the charging equipment and installation, load sharing or energy management may allow available charging power to be distributed between multiple EVSE units.
ESA’s current EV charging bulletin addresses multiple EVSE installations with communication and load-management capabilities.
The best approach depends on:
- how many kilometres each vehicle travels;
- how long both vehicles are parked overnight;
- whether both need to charge simultaneously;
- the electrical capacity of the home; and
- what compatible charging and energy-management equipment is available.
Planning for a second EV before the first charger is installed can help avoid unnecessary electrical work later.
Should I Upgrade to 200 Amps Anyway for Future Electrification?
Sometimes that can make sense.
Even if your current EV charger could operate with the existing 100 amp service, a larger service may be worth considering when substantial future electrification is already planned.
For example, you may eventually want:
- two EV chargers;
- an electric heat pump;
- electric water heating;
- an induction range;
- electric auxiliary heating;
- a hot tub;
- a basement apartment; or
- other major electrical additions.
In that situation, the decision is no longer simply about whether one EV charger fits on the existing service.
You are planning the electrical infrastructure for the home’s future requirements.
If an increase in service size is necessary, Toronto Hydro has a defined service-upgrade process that includes project review, design and coordination with the customer and contractor.
A 200 amp service should therefore be considered because the home’s actual and planned electrical needs justify it—not because an EV charger automatically requires 200 amps.
Does Having Space for a New Breaker Mean My 100 Amp Panel Can Handle the Charger?
No.
Physical space in the breaker panel and electrical capacity are separate issues.
You might have an unused breaker position while the home’s service is already close to its allowable electrical demand.
Alternatively, you could have adequate service capacity but insufficient physical breaker space in the existing panel.
An EV charger assessment should therefore examine both:
1. Can the panel accommodate the required circuit?
and
2. Can the electrical service accommodate the additional demand?
ESA emphasizes that EVs can use significant power and recommends making sure the home’s electrical panel can handle the additional load.
Is a 100 Amp Panel the Same as a 100 Amp Service?
Not always in the way homeowners use the terms.
People often say “100 amp panel” when they mean the entire home has a 100 amp electrical service.
The electrical panel is the distribution equipment containing breakers or other circuit-protection equipment. The electrical service refers more broadly to the electrical supply serving the property.
This distinction becomes important when discussing upgrades.
Replacing an old panel does not automatically mean the home’s electrical service has been increased.
If greater electrical capacity is required, the project may involve a service upgrade and coordination with Toronto Hydro in addition to work on the panel itself. Toronto Hydro maintains a specific process for requests to increase an existing electrical service size.
Do I Need a Permit to Install an EV Charger on a 100 Amp Service?
Yes, the EV charger installation is subject to Ontario electrical permitting requirements regardless of whether the home’s service is 100 amps or 200 amps.
ESA states that EV charger installations require an electrical permit—also referred to as a Notification of Work—to be filed before installation begins. When a homeowner hires someone to perform electrical work, Ontario requires that work to be carried out by a Licensed Electrical Contractor.
ESA also advises homeowners to make sure EV charging equipment carries an approved Canadian certification mark or label from a recognized certification or evaluation agency.
The fact that no service upgrade is required does not eliminate these requirements.
Should I Buy the Charger Before Checking My 100 Amp Service?
It is usually better to have a good understanding of your electrical capacity and charging requirements before committing to a particular charger.
The charger model can affect:
- maximum charging current;
- circuit requirements;
- whether the unit can be properly configured at a lower output;
- hardwired versus receptacle-based installation;
- energy-management compatibility; and
- future load-sharing possibilities.
Toronto Hydro recommends working with a Licensed Electrical Contractor when planning home charging so the contractor can assess the existing electrical capacity, determine charging options and explain installation requirements.
That can prevent a situation where you purchase a high-output charger only to discover that a different configuration or product would have been better suited to your home.
How Can I Prepare for a 100 Amp EV Charger Assessment?
Before contacting an electrical contractor, gather some basic information about your home and vehicle.
Useful information includes:
- a photo of the electrical panel;
- a photo showing the main breaker rating;
- photos of the panel labels;
- the EV make and model;
- the charger make and model you are considering;
- where the vehicle will normally be parked;
- where you want the charger installed;
- the approximate distance from the panel to the charger;
- whether the garage is attached or detached;
- major electric appliances in the home; and
- any planned future electrification projects.
Toronto Hydro customers can also review the peak-demand information available through Toronto Hydro’s online tools, which is specifically intended to assist with evaluating capacity for equipment such as EV chargers.
Having this information ready can make it easier to determine whether the existing 100 amp service is practical, whether load management should be considered, or whether an upgrade is warranted.
100 Amp vs. 200 Amp Service for an EV Charger
For EV charging, neither service size should be viewed in isolation.
A 100 amp service may be enough when:
The home’s existing demand and proposed charging load can be accommodated, or an appropriate approved energy-management solution is incorporated.
A 200 amp service may be appropriate when:
The existing demand plus planned electrical loads justify additional capacity, or the electrical assessment determines that the desired charging installation cannot be adequately supported by the existing service.
The goal is not simply to have the biggest electrical service possible.
The goal is to have enough electrical capacity for the home and its planned loads while installing the EV charger in accordance with Ontario electrical requirements.
Frequently Asked Questions
Can a 100 amp service run a Level 2 EV charger?
Yes, it can in some homes. Whether it will work at your property depends on the home’s electrical demand, the charger’s configured output and the installation design. ESA provides specific methods for determining whether an existing dwelling service needs to be upgraded when EVSE is added.
Do I need 200 amp service to charge an EV at home in Toronto?
Not automatically. Toronto Hydro states that adding an EV charger might require an electrical service upgrade, but not always, and recommends having a Licensed Electrical Contractor evaluate the home’s existing capacity first.
Is 100 amps enough for a 40 amp EV charger?
It may be, but the charger amperage cannot be considered by itself. The home’s existing electrical demand must also be evaluated. If capacity is limited, an appropriately configured charging output or qualifying Energy Management System may be considered.
Can I install a 48 amp EV charger on a 100 amp service?
Potentially, but whether that specific charging load can be supported depends on the home’s electrical capacity and the complete installation design. ESA permits certain fixed-in-place adjustable EVSE to be commissioned below their nameplate maximum when specified conditions are satisfied, which can provide additional design options in some installations.
Can load management avoid upgrading from 100 amps to 200 amps?
In some installations, yes. ESA permits Energy Management Systems to monitor loads and automatically control EV charging equipment. Whether an EMS is suitable for a particular home must be determined as part of the electrical design.
Does an EV charger require its own circuit?
ESA Bulletin 86-1-7 states that EVSE is generally required to be supplied by a separate branch circuit under Rule 86-300(1). The bulletin also provides for an exception where an EMS is installed and applicable conditions are satisfied.
Do I need an ESA permit if I keep my existing 100 amp service?
Yes. ESA states that EV charger installations require an electrical permit or Notification of Work before installation starts.
How do I know for sure whether my 100 amp service is enough?
Have a Licensed Electrical Contractor assess the home’s electrical service, existing demand and proposed charging equipment. Toronto Hydro specifically recommends this approach and provides a peak-demand tool that can assist homeowners and contractors in determining whether an electrical upgrade is necessary.
Final Answer
A 100 amp electrical service can be enough for a home EV charger in Toronto, and upgrading to 200 amps is not automatically required.
The answer depends on how much electrical demand your home already has, how much additional power the proposed EV charger will require, the charging rate you actually need, and whether an approved Energy Management System or suitable charger configuration can address capacity limitations.
A relatively lightly loaded 100 amp home may be able to accommodate Level 2 charging with the existing service. A home containing several major electrical loads may have less capacity available and could require load management, a different charger configuration or an electrical service upgrade.
The best approach is therefore to assess the existing 100 amp service before assuming a 200 amp upgrade is necessary.
