CEC Rule 8 Residential Load Calculation Guide
Rule 8 of the Canadian Electrical Code governs circuit loading and demand factors. For houses and dwelling units, Rule 8-200 is the rule every residential load calculator Canada must implement correctly. This guide explains the calculation path and links to our free live calculator.
Rule 8-200(1)(a) — Itemized method
Work through each load category: basic load from area, space heat and AC, range, water heating, EVSE, and additional loads. Each subsection has specific demand treatment. See Rule 8-200 explained for a concise rule reference.
Rule 8-200(1)(b) — Minimum load
Do not skip the minimum check. Even a large home with modest calculated loads may still require at least 100 A service when floor area triggers the 24,000 W floor.
From watts to service amps
Total calculated watts ÷ 240 V = amps (single-phase). Round up to standard service: 100, 125, 200, or 400 A. Read the residential service sizing guide for when each rating applies in practice.
EV and heat pump loads
Electrification retrofits often drive panel upgrades. See EV charger requirements and heat pump requirements.
Size the service conductors
After load calculation, size conductors with the conductor sizing calculator.