Which two NEC sections cover overhead and underground service conductor sizing and ampacity?

Which two NEC sections cover overhead and underground service conductor sizing and ampacity?

• A. 230.23 and 230.31
• B. 310.12 and 220.82
• C. 220.52 and 430.248
• D. 230.31 and 220.54

Answer: (A)

Sizing and ampacity of service conductors are determined by the rules for services in the NEC. For overhead and underground service conductors, two sections specifically address how big the conductors must be and how much current they can carry. One section sets the minimum size of service-entrance conductors based on the service rating and the protection provided, with temperature corrections applied from the general ampacity tables. The other section provides the allowable ampacity for service conductors and guides how to apply these sizes to different installation methods (overhead versus underground) so the conductor, overcurrent protection, and service equipment are properly coordinated. Together, these sections give the direct guidance you need to select the correct conductor size and confirm the ampacity for a service. Other NEC sections cover related topics like ambient temperature adjustments for general conductors or calculations for branch circuits and loads, but they do not specifically govern service conductor sizing and ampacity in the way these two do.

Sizing and ampacity of service conductors are determined by the rules for services in the NEC. For overhead and underground service conductors, two sections specifically address how big the conductors must be and how much current they can carry. One section sets the minimum size of service-entrance conductors based on the service rating and the protection provided, with temperature corrections applied from the general ampacity tables. The other section provides the allowable ampacity for service conductors and guides how to apply these sizes to different installation methods (overhead versus underground) so the conductor, overcurrent protection, and service equipment are properly coordinated. Together, these sections give the direct guidance you need to select the correct conductor size and confirm the ampacity for a service. Other NEC sections cover related topics like ambient temperature adjustments for general conductors or calculations for branch circuits and loads, but they do not specifically govern service conductor sizing and ampacity in the way these two do.