Importance of Fretting in Vibration Failures of Stranded Conductors

Surface fretting between conductor strands and support hardware plays an important part in the occurrence of conductor fatigue failures resulting from aeloian vibration. Examination of conductor strand failures from lines in service and from laboratory spans showed that fatigue cracks originated at fret marks in all cases. Laboratory fatigue tests indicate that fretting causes a reduction in the fatigue strength of conductor strands, below that of unfretted wires, by a factor of about 1.6.