Cyclic movement of cable — Its causes and effects on cable-sheath life

Results of a field survey and laboratory tests are presented in this paper showing the relationships between loading, conductor-temperature changes, movement in manholes and ducts, and sheath life for paper and lead cable. The record on underground 15-kv cable is included to emphasize the noninherent failures attributable to physical proportions of underground structures. Improvements in modern cable have permitted operation at increasing temperatures with few inherent failures.