Manhole 4 : A subsurface enclosure which personnel may enter and which is used for the purpose of installing, operating, and maintaining submersible equipment or cable
Department of Energy AREA SAFT, DOE Handbook, Electrical Safety (Appendix B), Acronyms and Definitions, DOE-HDBK-1092-98, D.C. 20585, USA 1998. http://energy.gov/sites/prod/files/2013/07/f2/hdbk 1092.pdf, (Electr Sfty - Amer) {43}