ABSTRACT
Electrical insulation materials are utilized to provide electrical isolation over the metallic conductors of underground cables. The insulating materials physically protect the conductor and provide a margin of safety. These materials are comprised of either synthetic or natural polymers. The polymeric insulation material selected for use may vary with the voltage class of the cable. Compatible polymeric shields are employed between the insulation and the conductor, and over the insulation to grade the voltage stress; these are comprised of flexible polymers blended with conducting carbon black that imparts the semiconducting characteristics.
