Section 8052 Of Article 3. Underground Transmission From California Public Utilities Code >> Division 4. >> Chapter 5. >> Article 3.

. No person shall build or rebuild in any subway, manhole, chamber, or underground room used or to be used to contain, encase, cover, or conduct any wire, cable, or appliance to conduct or handle electricity, any opening to outer air which is less than 26 inches if circular in shape, or less than 24 inches by 26 inches clear measurement if rectangular in shape.