Thermal aging of EPR cables

The results of thermal endurance tests performed on models of EPR (ethylene-propylene rubber) cables are presented. The problems of selecting the properties related to aging and their endpoints are discussed. A method for obtaining an objective failure criterion for different properties and a unique thermal endurance graph are described. The thermal life line thus obtained, pertinent to the electric strength, weight loss, tensile strength, and the thermal endurance indices, is reported. A life model is proposed, and its fit to the experimental results is shown. A life model that relates the slope of life lines to choice of endpoint is derived.<>