Armored fiber optic cables designed for direct burial cost $6-14 per linear foot. Conduit systems add $2-4 per foot but allow future cable additions. Handholes and. Total Project Costs: For commercial installations, expect costs ranging from $5,000 to $20,000 per mile for underground projects and from $40,000 to $60,000 per mile for aerial installations. In this guide, you'll get data‐driven ranges you can reference in bids, an illustrative cost breakdown, and. Prices typically range from about $0. Cost factors include material.