Original 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)