What the amp rating means
Your electrical service is the connection between the utility and your home: the cable from the street or pole, the meter, and the main breaker in your panel. Its amp rating is the most current your home can draw at once. Most houses are supplied at 120/240 V single-phase, so a bigger number means more total power available.
You can usually find your service size on the main breaker handle at the top of your panel. If you are not sure how to spot it, start with how to read your electrical panel.
Two numbers matter: the rating of the main breaker and the rating of the service equipment and conductors. They normally match, but not always. Only a licensed electrician can confirm what your service can actually carry.
Why so many Edmonton homes are on 100 A
Homes built from the 1950s through the 1970s often started with 60 A services, many of which were later upgraded to 100 A. For a house with a gas furnace, gas water heater and a modest number of appliances, 100 A can still be perfectly adequate.
The Canadian Electrical Code sets a minimum service size for a single dwelling, which for most houses is 100 A. The real requirement for your home is set by a calculated load based on floor area and the specific appliances you have, not by the minimum.
The picture changes quickly when you add large electric loads. The big ones are electric vehicle chargers, heat pumps and air conditioners, hot tubs, electric ranges and dryers, electric water heaters and basement suites with their own kitchens.
Signs 100 A may not be enough
- You are planning an EV charger, heat pump, hot tub or legal secondary suite.
- Your panel has no spare spaces left, or is full of tandem breakers.
- Lights dim when the dryer, A/C or microwave starts.
- Your main breaker has tripped, which suggests the whole house is reaching its limit.
- Your insurer or a home inspector has flagged the service as undersized.
Each of these is a reason to look closer, not proof you need 200 A. Sometimes a load calculation shows there is room, or an EV energy management device lets you add a charger without upgrading. See EV load management.
If you expect an EV, heat pump or suite in the next few years, upgrade once to a size that covers all of it. Doing the service twice costs more than doing it right the first time.
100 A vs 200 A at a glance
| 100 A service | 200 A service | |
|---|---|---|
| Typical fit | Gas-heated home, modest appliances | Homes with EV, heat pump, A/C, hot tub or suite |
| Panel spaces | Often 20 to 32 spaces | Usually 30 to 42 or more spaces |
| Room for growth | Limited | Comfortable for most homes |
| Upgrade work | None if it meets your needs | New panel and usually new service cable and meter base |
| Utility involvement | None | Disconnect and reconnect by the utility |
Some homes land in between with a 125 A or 150 A service. A load calculation tells you which size makes sense; bigger is not automatically better if you will never use it.
Alternatives to a full upgrade
A 200 A upgrade is not the only answer. Depending on what you want to add, one of these may get you there for less disruption:
- Load management for an EV charger. A device monitors your home's total draw and throttles or pauses charging when other loads are high, so the service is never overloaded.
- Choosing efficient equipment. A cold-climate heat pump sized correctly, or a heat pump water heater, can draw far less than older electric equipment.
- Rearranging circuits. If the problem is a full panel rather than total load, a subpanel or a larger panel on the same service may be enough.
- Staging the work. Wire the new circuits now and upgrade the service later, once the plan is clear.
Each option needs a load calculation behind it. An electrician can tell you which ones are realistic for your house and which would only delay an upgrade you will need anyway.
What an upgrade involves
A service upgrade is a bigger job than swapping a panel. It usually includes a new meter base and service cable, a new main panel, updated grounding and bonding, and reconnecting every existing circuit. The power is off for part of the day while the utility disconnects and reconnects you.
In Edmonton, the electrical permit comes from the City of Edmonton; elsewhere in Alberta it comes from the municipality or the province under the Safety Codes Act. The utility, EPCOR in most of the city, schedules the disconnect and reconnect. Alberta Electrical handles the permit, the coordination and the inspection as part of a service upgrade.
What drives cost is mostly the distance from the meter to the panel, whether the meter needs to move, whether the overhead or underground supply needs changes, how many circuits need reconnecting and whether any old wiring must be corrected to pass inspection.
The service conductors ahead of your main breaker cannot be switched off from inside your house. Service work must be done by a licensed electrician with a permit.
Common questions
Is 100 A enough for an EV charger?
Sometimes. It depends on your other loads and the charger size. A load calculation, and possibly a load management device, can often make it work without a full upgrade.
Does a 200 A service raise my power bill?
No. You pay for the energy you use, not the size of the service. A bigger service only gives you more capacity.
How long is the power off during an upgrade?
Usually part of a day. The exact time depends on the job and the utility's schedule, which we confirm with you before work starts.
Do I need a permit?
Yes. Service upgrades need an electrical permit and inspection. In Edmonton the City issues the permit; your electrician arranges it.
Codes and permit rules change and every building is different. For work on your system, talk to a licensed electrician and your local permit authority.