Thermal ratings of cable insulation and clarifying tests

The authors argue that it is important to emphasize that the entire power cable design must be tested when insulation thermal ratings are studied. Thermal expansion of the polymers (strand shield, insulation, insulation shield) must function unilaterally. All extruded layers must resist embrittlement and expansion concerns with effect on the metallic shield have to be taken into account. Some polymer systems will take a permanent set to irregular shapes around the shielding with resulting deleterious partial discharge and reduced breakdown voltages