Effects of Short-Time, High-Current Faults on Aged, Insulated Wire

Several previous studies of short-time, highcurrent faults on electrical distribution conductors have been made by the author. These studies are meant to simulate conditions where wire, properly protected by circuit breakers or fuses, suffers bolted short circuits. As usual in performance tests, unaged wire was used. The present study was initiated to determine how the damage done to wire insulation varies with age of the wire. The results how that the ability to resist damage by bolted short circuit is enhanced by the aging of the wire. This improvement continues until cracks form which partially penetrate the insulation.