Line breaking failure

Overhead power lines occasionally fail structurally (break) and fall to the ground where they can be a significant danger. The causes for line failure are many and represent the safety concern recognized by the National Electrical Safety Code (NESC) and electrical utilities. A rare occurrence of an overhead line breaking failure is used to illustrate the forensic engineering procedure. The theory and experimental evidence serve to prove that when an overhead energized multiconductor line, whether loaded or not, fails due to excessive tensional force, it can produce arcing between the conductors during and after the breaking of the line. The cause of an overhead line breakage cannot be determined solely from arcing evidence found on the conductors in the area of the break.