What is the maximum permitted length of the branch-circuit wiring for a 12 AWG conductor with a listed outlet branch-circuit type arc-fault circuit interrupter?

The maximum permitted length of branch-circuit wiring using a 12 AWG conductor with a listed outlet branch-circuit type arc-fault circuit interrupter is 70 feet. This limit is established based on the need to minimize voltage drop and ensure proper operation of the arc-fault circuit interrupter, which is crucial for safety in preventing electrical fires caused by arcing faults.

When circuits are designed, it's important to ensure that they operate effectively within their specified limits. Longer wiring lengths can lead to increased resistance and potentially insufficient voltage at the outlet, which could affect the arc-fault circuit interrupter's performance and reliability. Thus, the 70-foot maximum aligns with best practices and safety standards in electrical design, making it the correct option in this context.