Particle trapping sheath coupling for enclosed electric bus apparatus

In high voltage electric bus apparatus adapted for disposition with its longitudinal axis substantially horizontal, a tubular metallic sheath having an axially corrugated portion including at one end a terminal convolution forming an internal annular recess in said sheath and an adjacent portion axially flared toward said annular recess, said flared adjacent portion having its maximum vertical cross sectional axis proximate said recess and its minimum vertical cross sectional axis remote, and a tapered tubular sleeve of electrically conductive material fixedly mounted within said sheath adjacent the other end of said corrugated portion and extending through said corrugated portion in coaxial radially spaced relation, at least a portion of said sleeve axially flared toward a free end positioned in radially spaced relation, within said adjacent sheath portion, whereby said sleeve electrostatically shields said corrugated portion and said annular recess forms an electrostatic trap for free conductive particles within said sheath, said oppositely flared sleeve and adjacent sheath portion providing stepped and oppositely inclined bottom surfaces adapted to direct electrically levitated particles into said trap.