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Motor circuit sizing in Canada follows CEC Section 28 rather than the NEC's Article 430. While both codes use the concept of a motor full-load current (FLC) table as the basis for conductor and overcurrent protection sizing, the CEC organizes these requirements differently.
CEC Rule 28-106 specifies that motor branch circuit conductors must be rated at not less than 125% of the motor's full-load current as listed in CEC Tables 44 (single-phase motors) and 45 (three-phase motors). These tables list full-load current values by horsepower and voltage rating for standard AC induction motors. The values are similar to NEC Tables 430.248 and 430.250 but are drawn from CSA standards and may differ slightly for some motor ratings.
Overcurrent protection for motor branch circuits is addressed in CEC Rule 28-200. The maximum time-delay fuse or inverse-time circuit breaker size is 250% of the motor full-load current from Tables 44/45 for most applications — identical to the NEC maximum. Instantaneous trip breakers (motor circuit protectors) can be set up to 1300% of FLC in the CEC, compared to 1700% in the NEC for certain motor types.
Motor overload protection under CEC Rule 28-300 is set at 115% of the nameplate current for motors with a service factor of 1.15 or higher, and 125% for motors with unknown service factor — the same as NEC 430.52. This makes the overload sizing procedure essentially identical between codes.
One important CEC-specific requirement: Section 28 of the CEC has specific provisions for variable frequency drive (VFD) installations that extend beyond the basic NEC Article 430.120 guidance, including requirements for harmonic filtering and input/output protection that are more prescriptive in the CEC.
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Open CEC motor flc calculator →Each Canadian province and territory has adopted a version of the CEC. Verify the adopted edition and local amendments with your AHJ.
CEC Table 44 lists full-load currents for single-phase AC motors, and CEC Table 45 lists full-load currents for three-phase AC motors. These are the Canadian equivalents of NEC Tables 430.248 and 430.250.
CEC Rule 28-106 requires motor branch circuit conductors to be sized at not less than 125% of the motor full-load current from Tables 44 or 45. This is identical to the NEC 430.22 requirement.
CEC Rule 28-200 allows a maximum time-delay fuse or inverse-time breaker of 250% of motor FLC, the same as NEC 430.52. Instantaneous trip breakers are limited to 1300% of FLC in the CEC (vs. up to 1700% for some motors under the NEC).
Yes. CEC Section 28 includes specific requirements for VFD installations, including conductor sizing for the drive output, harmonic considerations, and protection requirements. These provisions are more prescriptive than the basic NEC Article 430.120 guidance.
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.