Which statement about conductor sizing is accurate?

• A. The minimum for power circuits is #18 AWG
• B. The minimum for control circuits is #14 AWG
• C. The minimum for power circuits is #12 AWG
• D. The minimum for power circuits is #14 AWG

Answer: (D)

Conductor sizing is all about matching the conductor’s ampacity to the overcurrent protection and the circuit’s load. For power circuits, the smallest copper size you’d typically see is 14 AWG, which is rated for about 15 A in common insulation. That makes 14 AWG the standard minimum for general power circuits like lighting and receptacle circuits protected by 15 A breakers. If a circuit requires more current (such as a 20 A circuit), the conductor must be at least 12 AWG. Smaller conductors, such as 18 AWG, aren’t suitable for power circuits because they can overheat under normal loads. So stating that the minimum size for power circuits is 14 AWG aligns with how typical residential power circuits are wired.