Laboratory and Service Aging Tests of Paper - Insulated, Three-Conductor Cables for 12-kV Service

Forty 3-conductor cables for 12-kV service were subjected to stability studies in laboratory aging tests and/or in experimental service operation. The main purpose for this was the determination of 1) difference between the stability of shielded and of belted cables, 2) minimum safe insulation thickness for shielded cables, and 3) maximum permissible temperatures for normal and emergency operation. The results showed superiority of shielded cables and marked effects of insulation thickness and temperatures upon stability.