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Canadian consumer service sizing — the calculation that determines the minimum service entrance ampacity for a building — is governed by CEC Rule 8-200 for single-family dwellings and Rule 8-210 for commercial and multi-unit applications. The term "consumer service" in the CEC is the equivalent of the NEC's "service entrance."
CEC Rule 8-200 establishes the demand calculation for single dwellings. The calculation applies a demand factor to the total connected load: 100% on the first 10,000 VA, then 25% on the remainder. This typically results in a lower calculated demand than the NEC optional method (which uses 40% on the remainder above 10,000 VA) and allows many Canadian homes to be served by a smaller service entrance.
The resulting calculated demand is divided by the service voltage (240V for single-phase, 208V or 240V for three-phase) to determine the service ampacity. The minimum service ampacity must be the next standard service size (60A, 100A, 125A, 150A, 200A, 320A, or 400A) at or above the calculated value. CEC 2021 and 2024 set 100A as the minimum service for any single-family dwelling regardless of calculated demand.
Utility requirements add another layer: Canadian utilities (BC Hydro, Hydro One in Ontario, ATCO in Alberta, etc.) set minimum service entrance requirements that may exceed the CEC minimums. For example, some utilities require a minimum 200A service for new residential construction regardless of the CEC calculation result.
This calculator performs the CEC Rule 8-200 demand calculation, shows the required minimum service size, and flags provincial utility minimum service requirements where known.
SparkShift pre-selects CEC mode. Results cite CEC rules (8-200) for permit documentation.
Open CEC dwelling load calculator →Each Canadian province and territory has adopted a version of the CEC. Verify the adopted edition and local amendments with your AHJ.
A 'consumer service' in the CEC is the electrical service entrance — the conductors and equipment from the utility connection point to the service disconnect and main panel. It is equivalent to the NEC's 'service entrance.'
CEC 2021 and 2024 require a minimum 100A service for single-family dwellings. The calculated demand under Rule 8-200 must not require a service smaller than 100A. Many utilities require 200A for new construction.
Apply the demand factors from Rule 8-200: 100% on the first 10,000 VA of connected load, 25% on the remainder. Add electric heat or air conditioning (the larger load) at 100%. Divide the total by the service voltage (usually 240V) to get minimum ampacity.
Yes. BC Hydro, Hydro One, ATCO, and other Canadian utilities often require a minimum 200A service for new residential construction regardless of the CEC Rule 8-200 calculated demand. Always confirm with the serving utility before finalizing the service design.
Disclaimer: SparkShift calculators are provided for informational purposes. Always verify calculations against the adopted CEC edition in your province and confirm requirements with your local authority having jurisdiction (AHJ) before commencing work. The CEC edition adopted may differ by province — Ontario uses the OESC, BC uses the BC Electrical Safety Regulation, and other provinces have their own adopted editions.