CEC Rule 8-200
Dwelling Unit Service and Feeder Load Calculation
In the Canadian Electrical Code, Rule 8-200 is where you go to figure out how big your service needs to be for a house. The approach is a bit different from the NEC. You start with a base load of 5,000 watts that covers the first 90 square metres of living area. For each additional 90 square metres (or fraction thereof), you add 1,000 watts. On top of that, you add the loads for a single electric range (starting at 6,000 watts, with 40 percent of anything over 12 kW), electric heating, air conditioning, water heater, and other major equipment. There is also an alternative method that lets you use a flat 24,000-watt base for homes 80 square metres or larger, or 14,400 watts for smaller homes. Living area is calculated from inside dimensions (not outside like the NEC), and basements that exceed 1.8 metres in height contribute 75 percent of their area to the total. The CEC uses metric units and watts rather than the NEC's imperial units and volt-amperes, which is one of the biggest practical differences for electricians crossing the border.
When You Need This
- Sizing the main electrical service for a new single-family home in Canada
- Upgrading a residential service and need to prove the new panel size is adequate
- Working on a cross-border project and need to understand how Canadian dwelling load calculations differ from NEC methods
- Preparing for the Red Seal exam or a provincial electrical licensing exam in Canada
Key Points
Common Mistakes
Using NEC exterior dimensions instead of CEC interior dimensions for the floor area measurement
Confusing the CEC basic load (5,000 W) with the NEC approach (3 VA per square foot) — they are fundamentally different methods
Forgetting the 75-percent rule for below-grade living areas — basements count, but at a reduced percentage
Using the 24,000 W alternative base without confirming the floor area exceeds 80 square metres
Mixing up watts and volt-amperes — the CEC works in watts, while the NEC works in VA, and the two are not always interchangeable
Exam Tip
For the Red Seal exam, know both the standard and alternative basic load methods. The alternative (24,000 W flat base) is often faster. Remember: basements at 75 percent, interior dimensions, and the range calculation starts at 6,000 W with 40 percent on the excess above 12 kW.
Frequently Asked Questions
The CEC uses a base load in watts plus incremental additions based on floor area measured from inside dimensions. The NEC uses VA per square foot from outside dimensions plus separate demand factors for each load category. The CEC approach tends to be simpler with fewer separate demand factor tables to consult.
Rule 8-200(2) covers the calculation for service or feeder conductors supplying two or more dwelling units of row housing, including single dwellings with secondary suites. The base calculation is similar but is applied per unit.
No. The 24,000-watt alternative is only available for dwellings with a floor area of 80 square metres or more. For smaller homes, the alternative basic load is 14,400 watts.
Inline Tools
Dwelling Load Calculator
Calculate residential service load per NEC 220
Related Code Sections
This is an educational summary, not the official code text. The NEC® is a registered trademark and copyright © National Fire Protection Association (NFPA). The CEC is copyright © CSA Group. For official code text, visit nfpa.org or csagroup.org. SparkShift is not affiliated with NFPA or CSA Group.