A journeyperson is installing a new 200 A, 600 V service entrance conductor in a commercial building. The conductors are aluminum and will be run in rigid PVC conduit underground. According to the Canadian Electrical Code (CEC), what is the minimum acceptable diameter for this conduit, assuming a standard 3-conductor plus neutral configuration and considering voltage drop will be addressed by up-sizing conductors if necessary?

Question: A journeyperson is installing a new 200 A, 600 V service entrance conductor in a commercial building. The conductors are aluminum and will be run in rigid PVC conduit underground. According to the Canadian Electrical Code (CEC), what is the minimum acceptable diameter for this conduit, assuming a standard 3-conductor plus neutral configuration and considering voltage drop will be addressed by up-sizing conductors if necessary?

Answer options:

• 63 mm (2 ½ in.)
• 78 mm (3 in.) ✅ 103 mm (4 in.)
• 129 mm (5 in.)

Correct answer: 103 mm (4 in.)

Explanation: For 200 A aluminum conductors (typically 250 kcmil or 300 kcmil depending on insulation and conditions) and a 3-conductor plus neutral configuration, a 103 mm (4 in.) rigid PVC conduit is generally required to meet conductor fill requirements, as per CEC Table 6 and Appendix B. Smaller conduits would exceed the allowable fill percentage.