Manholes: What Does The '99 NEC Have To Say? | ECM
WEBMay 1, 1999 · Round access openings in a manhole shall not be less than 26 in. (659 mm) in diameter. Exception: A manhole that has a fixed ladder that does not obstruct the opening, or that contains only one or more of the following shall be permitted to reduce the minimum cover diameter to 2 ft (608 mm): a. Optical fiber cables as covered in Article .