What is the minimum conductor gauge for a bus conductor in this practice?

• A. #1 AWG or larger
• B. #2 AWG or larger
• C. #4 AWG or larger
• D. #6 AWG or larger

Answer: (B)

Sizing the bus conductor comes down to ampacity—the wire must be large enough to carry the expected current without overheating and while keeping voltage drop within acceptable limits. In this practice, #2 AWG is the smallest conductor that meets the required current-carrying capability for a bus conductor, with room for normal operating conditions and fault scenarios. Using a smaller gauge (like #6 or #4) would not provide adequate ampacity, risking overheating and reliability issues. Using a larger conductor (such as #1 AWG or bigger) would still be acceptable from a safety standpoint, but it isn’t the minimum size required.