Which value represents a maximum length for installed flexible metal conduit?

• A. 30 feet
• B. 40 feet
• C. 20 feet
• D. 10 feet

Answer: (C)

FMC is intended for short, flexible connections rather than long runs. Because it can be more easily damaged and its bending and termination requirements become harder to maintain over long distances, the code restricts how long a single continuous FMC run can be between terminations.

The longest allowable single run in typical practice is 20 feet. If you need to cover a longer distance, you should use a different raceway (like rigid metal conduit or EMT) or introduce pull points so that each FMC segment remains within its limit. The other lengths shown exceed the maximum, or are simply shorter runs that don’t reflect the allowed maximum length.