Fiber optic cables are ordered in specific lengths as calculated by an OSP (Outside Plant) Engineer. Their lengths are determined by measuring the distance between splice manholes plus the excess cable length required for racking the cable at all manhole locations and slack storage. Fiber optic cable is sensitive to excessive pulling, bending, and crush forces. To ensure all specifications are met, consult the specific cable specification sheet for the cable you. Using Conduits to Protect Underground Fiber Cables In areas exposed to moisture, mechanical stress, or future excavation, installing fiber optic cable within an underground conduit provides an additional layer of protection. On long runs, use proper lubricants and make sure they are compatible with the cable jacket. On really. The Fiber Optic Association, Inc. 2 meters (3-4 feet) deep to reduce the likelihood of accidentally being dug up. In extreme cold climates, cables may need to be buried at greater depths where there temperatures are colder and frost penetrates to. Recommendations for Fiber Optic Cable Installation Where reels are supplied with protective material fitted over the cable, the protection should remain in place until the cable will be installed. During installation, all curvatures should be smooth.