What ampacity is required for motor feeder tap conductors?

The correct answer regarding the ampacity required for motor feeder tap conductors is that they must be at least one-third that of the feeder conductors. This requirement is outlined in the National Electrical Code (NEC), which states that when tapping conductors to supply motors, the tap conductors need to be sized in accordance with the load they are expected to carry, ensuring they can handle the appropriate current without overheating or risking fire hazards.

This one-third ratio provides a margin for safety and equipment protection, as motor starting loads can often exceed normal running currents significantly. By allowing for a minimum of one-third of the feeder conductors’ ampacity, the design takes into account transient load conditions while still allowing for efficient operation.

Higher ampacity ratios, such as one-half or equal to the feeder conductors, are not required in this context and would not reflect an understanding of the NEC's tap conductor guidelines, which balance safety, efficiency, and practical considerations in electrical installations.