The old cable can be pulled out of the conduit and the new pulled in without extensive and expensive digging. Placing cable into empty ducts in these banks allows changes and growth of the city s cable infrastructure without major traffic disruptions from cutting and trenching of the street. A large percent of underground fiber optic cable is installed in conduit. Because fiber optic cable is typically 10 - 20 mm in diameter, it has lower breaking strength and is more easily damaged than a 100 mm twisted pair copper cable. Conduit offers needed protection for this fiber optic cable.
Cable pulling is well known to cable installers throughout the world.
For more than 50 years, millions of kilometers of electrical and communications cable have been installed using this basic method. Proper answers to these questions mean better, more efficient cable installations, with less damaged cable and longer cable life. The maximum recommended tension varies with both the size and type of cable. Fiber optic and coaxial cables typically have tensile strengths of 200 to 2500 Newtons. Large copper cables may have tensile strengths as high as 15 kN. The cable's manufacturer can provide the maximum installation tension for any particular cable.