Bury cables from 12-36 inches (or 30-90 cm) deep. Where plant life, sidewalks, and other utilities already disrupt earth, it's safer to bury at as little as 24 inches or 60 cm, using protective conduits to limit the likelihood of damaged cables by inexperienced maintenance or. Bury cables from 12-36 inches (or 30-90 cm) deep. 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. Conventional trenching is suitable for open areas, while narrow trenching or horizontal directional drilling (HDD) is often preferred in urban or high-traffic environments to minimize disruption during underground fiber optic cable installation. Using Conduits to Protect Underground Fiber Cables In. trenches deeper than one meter shall be dug as necessary and DWC pipes shall be placed to protect the optical fiber cables. However, simply hitting this depth isn't enough to guarantee your network survives. Factors like the. Depths are established based on principles of protecting cables from physical impact and dispersing adverse weather effects should they encounter water, frozen temps, etc. Shallower depths are permissible when individual lengths are placed within conduits.