General Order 128
Section IV
Requirements for Communication Systems
42.7 Covers
Manholes and handholes, while not being worked in shall be securely
closed by covers of sufficient strength to sustain such loads as may reasonably
be imposed upon them, and arrangement shall be such that a tool or appliance
shall be required for their opening and cover removal (Also See Rule 17.8
and Appendix B, Fig. 9
).