Outdoor epoxy shell bushing for electrical installations

Claim 1

A high voltage electrical bushing for forming a high voltage connection to electrical apparatus emplaced within a housing; said bushing comprising: an elongated shell formed of a dielectric material consisting of a molded thermosetting resin; said shell having an axially extending passage of a first diameter; an electrical terminal positioned at each end of said passage; an electrical conductor disposed along the axis of said passage between said electrical terminals; said conductor having an outer diameter substantially less than said first diameter to define an annular insulating volume between an exterior surface of said conductor and an interior surface of said shell; a cylindrical, electrically conductive, non-magnetic shield coaxially embedded in said shell and disposed about an intermediate portion of said conductor between said electrical terminals; said shield having a diameter substan-tially greater than said first diameter and comprising a cylinder of a conductive mesh having opposed first and second ends, each of said ends being formed with a rounded rim portion to reduce the electric field gradient thereat; said insulating volume being filled solely with a gaseous insulating material having a dielectric constant less than the dielectric constant of said shell material and being free of any conductive material therein and said interior surface of said axially extending passage presenting an electrically insulative surface to said gaseous insulative material, thereby to reduce the curvature of equipotential lines adjacent to each end of said shield to reduce corona discharge thereat; said shell including an integral radially outwardly extending flange adjacent to said intermediate portion; said flange having a first surface adapted to bear upon an exterior surface of said apparatus housing; and mounting means for mounting said electrical bushing comprising a plurality of conductive fastening members accessible through said first flange surface, and electrically conductive means electrically connecting each of said fastening members to said shield.