Such manhole shall be pre cast RCC Cylindrical pipe (spun concrete) with minimum wall thickness of 80mm and shall include 08mrn or more steel reinforcement. The Fiber Optic Association, Inc. (FOA) was founded in 1995 to help develop the workforce to build the fiber optic networks to support a rapid expansion in communications and the Internet. FO-VC2 JOINT USE - VERICAL MIDSPAN CLEARANCES 48. FO-RI JOINT USE RISER. Recommendations for Fiber Optic Cable Storage Where reels are supplied with protective material fitted over the cable, the protection should remain in place until the cable has been installed. If the protection is removed prior to installation (for inspection purposes for example) then it must be. Underground cables are pulled in conduit that is buried underground, usually 1-1. 2 meters (3-4 feet) deep to reduce the likelihood of accidentally being dug up. You should pull on the fiber cable strength members only! Never exceed the maximum pulling load rating. On long runs, use proper lubricants and make sure they are compatible with the cable jacket.