The feeder conductor ampacity shall not be less than that of the service-entrance conductors where the feeder conductors carry the total load supplied by service-entrance conductors with an ampacity of ___ amps or less.

The feeder conductor ampacity shall not be less than that of the service-entrance conductors where the feeder conductors carry the total load supplied by service-entrance conductors with an ampacity of ___ amps or less.

• A. 50
• B. 125
• C. 55
• D. 100

Answer: (C)

When a feeder is expected to carry the total load that would be supplied by the service-entrance conductors, the feeder’s ampacity must be at least as large as the service-entrance ampacity. The code sets a cutoff value: if the service-entrance conductors have an ampacity of 55 amps or less, the feeder must have an ampacity not less than that same rating. This ensures the feeder can safely carry the full service load without overheating when the feeder ends up carrying all of the service’s load. Therefore, the threshold used here is 55 amps, making the feeder’s required ampacity at least 55 amps in that scenario. The other numbers don’t define that specific threshold.

When a feeder is expected to carry the total load that would be supplied by the service-entrance conductors, the feeder’s ampacity must be at least as large as the service-entrance ampacity. The code sets a cutoff value: if the service-entrance conductors have an ampacity of 55 amps or less, the feeder must have an ampacity not less than that same rating. This ensures the feeder can safely carry the full service load without overheating when the feeder ends up carrying all of the service’s load. Therefore, the threshold used here is 55 amps, making the feeder’s required ampacity at least 55 amps in that scenario. The other numbers don’t define that specific threshold.