Abstract: An elongate high voltage insulator is formed of a rod or tube of insulating material, with a pair of electrodes spaced apart longitudinally thereof. At least part, and preferably the whole of the outer surface of the insulating material is covered by a layer of material including a particulate filler of varistor powder in a matrix having a switching electrical stress-controlling characteristic that is in electrical contact with each of the electrodes. The insulator core may be made of porcelain, and the stress-controlling material may be zinc oxide.

Abstract: An elongate high voltage insulator (2) is formed of a rod or tube (4) of insulating material, with a pair of electrodes (6) spaced apart longitudinally thereof. At least part, and preferably the whole of the outer surface of the insulating material (4) is covered by a layer of material (8) comprising a particulate filler of varistor powder in a matrix having a switching electrical stress-controlling characteristic that is in electrical contact with each of the electrodes (6). The insulator core (4) may be made of porcelain, and the stress-controlling material (8) may comprise zinc oxide.

Abstract: Articles and methods are provided for enclosing an elongate substrate. A container is provided which is configured to receive the elongate substrate. A first polymeric sealing material having a first softening point and a first melt viscosity is positioned in the container. A second polymeric sealing material is positioned in the container between the first sealing material and an end of the container. The second sealing material has a second softening point lower than the first softening point and a second melt viscosity lower at a defined temperature than the fist melt viscosity.