For a new single-phase dwelling rated at 200 A with no adjustments, what is the minimum size copper service conductors?

For a new single-phase dwelling rated at 200 A with no adjustments, what is the minimum size copper service conductors?

• A. 1/0 AWG
• B. 3/0 AWG
• C. 2/0 AWG
• D. 4/0 AWG

Answer: (C)

Sizing service conductors is about picking a copper size whose ampacity meets or exceeds the service rating, with no adjustment factors applied. For a 200 A single-phase dwelling, you consult the NEC ampacity table for copper conductors and find the smallest size that can carry at least 200 A. The 1/0 AWG size does not provide enough ampacity in the common insulation ratings used for service entrances. The next size up, 2/0 AWG, has an ampacity at or above 200 A, making it the smallest copper conductor that meets the requirement. Larger sizes like 3/0 or 4/0 would also work but aren’t the minimum. Hence, the minimum copper service conductors for a 200 A service, with no adjustments, are 2/0 AWG.

Sizing service conductors is about picking a copper size whose ampacity meets or exceeds the service rating, with no adjustment factors applied. For a 200 A single-phase dwelling, you consult the NEC ampacity table for copper conductors and find the smallest size that can carry at least 200 A. The 1/0 AWG size does not provide enough ampacity in the common insulation ratings used for service entrances. The next size up, 2/0 AWG, has an ampacity at or above 200 A, making it the smallest copper conductor that meets the requirement. Larger sizes like 3/0 or 4/0 would also work but aren’t the minimum. Hence, the minimum copper service conductors for a 200 A service, with no adjustments, are 2/0 AWG.