The development of underjacket moisture barrier cable as a counter measure against treeing

Materials have been developed to allow rapid commercialization of underjacket moisture barrier sheathed medium-voltage power cables. Plastic-coated aluminium and copper tapes meet the needs for a radial metallic moisture barrier. These tapes have outstanding initial adhesion to polyethylene, chlorinated polyethylene, or polyvinyl chloride jackets and excellent bond stability during thermal loading, temperature cycling, water aging, and exposure to elevated temperatures. Semiconductive water-swellable tapes have been developed which function as cushion (thermal expansion) layers and longitudinal water blocks. These tapes are commercially available from several sources. Commercially available hot melt adhesives are effective in sealing the overlap of the metallic moisture barrier and meet the criteria for adhesion and bond retention. These materials have been combined to produce a viable water impervious medium-voltage power cable. Underjacket moisture barrier cables have been commercially manufactured and have passed several key industry tests. The properties and installation characteristics of the cable are detailed