Which conductor size is typical for a 20 A circuit in residential wiring?

Which conductor size is typical for a 20 A circuit in residential wiring?

• A. 12 AWG conductor for 20 A
• B. 8 AWG conductor for 20 A
• C. 14 AWG conductor for 20 A
• D. 16 AWG conductor for 20 A

Answer: (A)

The key idea is ampacity—the maximum current a conductor can safely carry—and matching it to the overcurrent protection (the breaker). For a 20 A circuit, the wire must be rated for at least 20 A. In typical residential wiring, the conductor that has that 20 A rating is the mid-size option commonly used for general outlets and lighting; it’s sized to safely carry 20 A and is standard for these circuits. Smaller conductors, like those used for 15 A circuits, aren’t allowed on a 20 A circuit because they aren’t rated to handle that much current. Larger gauges exist too, but they’re overkill for a standard 20 A branch circuit. So the typical choice is the wire that is rated for 20 A.

The key idea is ampacity—the maximum current a conductor can safely carry—and matching it to the overcurrent protection (the breaker). For a 20 A circuit, the wire must be rated for at least 20 A. In typical residential wiring, the conductor that has that 20 A rating is the mid-size option commonly used for general outlets and lighting; it’s sized to safely carry 20 A and is standard for these circuits. Smaller conductors, like those used for 15 A circuits, aren’t allowed on a 20 A circuit because they aren’t rated to handle that much current. Larger gauges exist too, but they’re overkill for a standard 20 A branch circuit. So the typical choice is the wire that is rated for 20 A.