Calculator · Drawing E-501
Home electrical load calculator
Estimate a single dwelling’s calculated load by the Canadian Electrical Code method the City of Calgary uses on its load-calculation sheet, and see whether 60 A, 100 A or 200 A is enough.
CCT 01How it works
The Canadian Electrical Code sets the minimum capacity of a single dwelling’s service in Rule 8-200. The City of Calgary’s load-calculation sheet lays the method out line by line1, and this calculator follows it:
- A basic load of 5,000 W for the first 90 m² of living area, plus 1,000 W for each additional 90 m² or part of 90 m².
- Electric space heating (Section 62) and air conditioning, subject to Rule 8-106(4): when the two cannot run at the same time, only the larger counts.
- An electric range at 6,000 W, plus 40% of any rating above 12 kW.
- Tankless water heaters and heaters for pools, hot tubs and spas at 100%.
- Electric vehicle charging equipment at 100%.
- Every other load over 1,500 W at 25% of its nameplate if an electric range is included. With no electric range, those loads count at 100% up to 6,000 W and 25% above that. Nameplate ratings are used for each load above 1,500 W2.
The service must be at least the greater of that total or a floor minimum: 100 A when the floor area excluding the basement is 80 m² or more, and 60 A below that1. Amps are the total watts divided by 240 V.
CCT 02Assumptions and limits
- Electric heat is counted at 100%. Section 62 allows demand factors on larger heating loads, so a result with electric heat is on the conservative side.
- An EV charger whose current setting a user can change without an electrician is counted at its maximum3. With an energy management system (EVEMS), the calculation changes: see EV charging at home.
- This is a single-dwelling estimate. A house with a secondary suite or a backyard suite uses Rule 8-202 demand factors across the units, and the City asks for the full sheet with the permit4.
- Only an electrician’s calculation, submitted with the permit, decides the service size. Whether ENMAX can supply a larger service at your address is a separate question: see ENMAX service connections.
Questions people ask
Is a 100 amp service enough for a house in Calgary?
Often, for a gas-heated house of moderate size with no EV charger. The method above usually lands well under 100 A for that house. Adding a Level 2 charger at 100%, a hot tub heater at 100% or electric heat is what pushes the total past it. Run your own numbers above, then read 100 A vs 200 A service.
Can I add an EV charger to a 100 amp panel?
Sometimes. If the calculated load plus the charger stays within the service, yes. If not, an EV energy management system can share capacity with other loads instead of upgrading. Either way, EV-charger wiring in Calgary needs a contractor permit, not a homeowner permit. See EV charger installation.
What is living area for a load calculation?
Rule 8-110 defines it. It is not simply the listing square footage, because basement space is treated differently from floors above grade. Use your best estimate here, and your electrician will calculate it exactly for the permit.
Does the calculator replace an electrician’s load calculation?
No. It shows the method and gives you a planning number before you ask for quotes. The permit needs a calculation by the electrical contractor, who checks every nameplate.
Sources
- Electrical load calculation template for secondary and backyard suites (CEC Rule 8-200)The City of Calgary · retrieved 2026-09-25
- STANDATA bulletin 24-ECB-008 Circuit loading and demand factorsAlberta Municipal Affairs · April 2025
- STANDATA interpretation 24-ECI-086 Electric vehicle charging systemsAlberta Municipal Affairs · April 2025
- Homeowner electrical and plumbing permitsCity of Calgary · retrieved 2026-09-25