Understanding the mechanics of aerial cable installation is essential to the cable engineer for proper plant design and for maximum cable plant reliability and longevity. A key part of that understanding is the calculation of sags and tensions. Although basic sag and tension equations are available, little is available on calculating sag and tension with changing temperature and load.
This paper extends the basic sag and tension equations to address these effects, and gives the ability to solve integrally supported (Figure 8) cable, tightly lashed cable, and unequal elevation problems. The equations are applied to several basic tension and clearance problems and further, to analyze expansion loop life, tight lashing, cable buckling, and center conductor pullouts. Obscure cable failure modes caused by wind gusting, solar heating and radiative cooling are discussed.