The largest 3-pole circuit breaker that can be used to protect a 12 AWG copper Type SO flexible cord is ___ A.

The largest 3-pole circuit breaker that can be used to protect a 12 AWG copper Type SO flexible cord is ___ A.

• A. 30
• B. 25
• C. 15
• D. 20

Answer: (D)

When protecting a flexible cord, the overcurrent device must not exceed the ampacity of the conductors inside the cord. For a 12 AWG copper conductor in a Type SO flexible cord, the ampacity is 20 A. That means any protective device, including a 3-pole breaker, cannot be rated higher than 20 A. Using a larger breaker could allow excessive current that overheats the cord insulation, posing a fire risk. Therefore, the largest 3-pole breaker you can use is 20 A.

When protecting a flexible cord, the overcurrent device must not exceed the ampacity of the conductors inside the cord. For a 12 AWG copper conductor in a Type SO flexible cord, the ampacity is 20 A. That means any protective device, including a 3-pole breaker, cannot be rated higher than 20 A. Using a larger breaker could allow excessive current that overheats the cord insulation, posing a fire risk. Therefore, the largest 3-pole breaker you can use is 20 A.