Direct-burial fiber cable eliminates the need for continuous conduit runs and can be faster and more cost-effective on long, open runs. This guide explains the common. 1. 01 This procedure provides general information for the installation of Prysmian fiber optic cables in direct buried applications. The methods described are intended for guideline use only, as it is impossible to cover all the various conditions that may arise during an installation. Individual. ble may extend of the reel and beco ssible safety hazard and/or damaging the cable. It forms a critical backbone for modern communication networks across both urban and rural environments. In extreme cold climates, cables may need to be buried at greater depths where there temperatures are colder and frost penetrates to. When planning a fiber optic network installation, one of the most common questions is: How deep are fiber optic cables buried? Proper burial depth is critical for the safety, durability, and performance of your communication infrastructure.