101 describes characteristics, construction and test methods of optical fibre cables for buried application. Note that Recommendation ITU-T L. The following formulas may be used to determine general guidelines for installing Corning Optical Communications fiber optic cable; however, refer to the cable specifi simply double the minimum working bend radius. Split cable guides and split 40-in. 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. Match trench method with the correct underground fiber structure (GYTS, GYTA53, GYTY53, micro-duct).