Which section contains the sizing of single-phase dwelling services and feeders?

Which section contains the sizing of single-phase dwelling services and feeders?

• A. NEC Section 310.12
• B. NEC Table 430.248
• C. NEC Section 220.82(C)
• D. NEC Section 230.23

Answer: (A)

Sizing the conductors for dwelling services and their feeders is handled by a section that provides the ampacity values to use for dwelling units. This section gives the direct method to determine how large the service and feeder conductors must be, by tying the calculated load (from the dwelling calculation rules) to the appropriate conductor ampacity in the general ampacity tables, while accounting for the insulation temperature rating. In practice, you first determine the dwelling’s load, then select a conductor size whose ampacity meets or exceeds that load using the provisions in this section. That makes it the go-to rule for sizing single‑phase dwelling services and feeders. The other references relate to different aspects: one covers motor circuits and protections, another outlines dwelling-load calculations, and another general service conductor guidance that isn’t the specific dwelling-service sizing rule.

Sizing the conductors for dwelling services and their feeders is handled by a section that provides the ampacity values to use for dwelling units. This section gives the direct method to determine how large the service and feeder conductors must be, by tying the calculated load (from the dwelling calculation rules) to the appropriate conductor ampacity in the general ampacity tables, while accounting for the insulation temperature rating. In practice, you first determine the dwelling’s load, then select a conductor size whose ampacity meets or exceeds that load using the provisions in this section. That makes it the go-to rule for sizing single‑phase dwelling services and feeders.

The other references relate to different aspects: one covers motor circuits and protections, another outlines dwelling-load calculations, and another general service conductor guidance that isn’t the specific dwelling-service sizing rule.