Impregnation of Cables

In the mass impregnation process, paper insulated cables are wound on a drum or in a circular tray that is placed in a heated tank to dry the insulation at low pressure. Hot impregnating compound is then admitted and the vessel maintained at about 1,200°C (1,920°F) under positive pressure. The total drying and impregnating time is of the order of 20 to 70 hours depending on cable type and voltage.