Abstract: The suspension insulator comprises an insulating skirt of quenched glass or of porcelain having an underside in which a pin is fixed by a cement-based binder, a sacrificial ring made of zinc in contact with the binder and surrounding the pin, and an annular plug of electrically conductive material disposed between the insulating skirt and the sacrificial ring in such a manner as to provide sealing that prevents leakage currents from passing through the binder. The plug serves to avoid corrosion phenomena of the pin and the risk of the insulator exploding.

Abstract: An electrical insulator (1) of the type comprising at least one dielectric (2) and an iron or steel cap (3) fixed axially on the dielectric has a device for protecting the cap against corrosion as well as electric arcs. In one embodiment (FIGS. 1-3), the protection device comprises a zinc or aluminum part (10) shaped as a dish with a center hole (11) and outlet holes (12) for the egress of rainwater. The outside wall (13) of the part (10) curves upwardly toward the cap (3) and a portion of the part (10) is disposed between the base (6) of the cap (3) and the outer surface (7) of the dielectric (2). In another embodiment (FIG. 4), the protection device comprises a solid body of revolution (30) of semi-toroidal shape which is formed of zinc or aluminum and is cast directly around the base (6) of the cap (3) and has a thin flange extending between the base (6 )of the cap (3) and the outer surface (7) of the dielectric (2).