Effect of elevated temperature operation on the tensile strength of overhead conductors

The loss of tensile strength of wires and stranded conductors operating at elevated temperatures depends on the cold work experienced in their manufacture, and the temperature and the time duration at that temperature. It is shown that existing equations for calculating the loss of strength for aluminum, 6201 aluminum-alloy and copper conductors are unsatisfactory, and a new equation is proposed. Published experimental data are examined, and possible relationships between the rate of loss of strength and the various stages of recovery and recrystallization are identified.