Placing Fiber Optic Cables in Multioccupied Ducts

Placing fiber optic cable (FOC) in duct containing copper cable can save millions of construction dollars. This paper describes techniques used successfully in rodding duct over copper cables in actual field installations-a necessary and most critical step preparatory to the actual placement of the FOC. In addition, a mathematical model useful in planning and predicting expected FOC pulling tensions for arbitrary duct routes containing copper cables is also presented. The analysis indicates that, in general, the expected FOC pulling tensions vary inversely with the diameters of the FOC and winch line. The results of a typical cable pulling tension calculation are also given.