Improved insulator configurations are provided for retarding corrosion of the central conductor pin of a coaxial cable connector. In a first embodiment of the invention, the distal end of the dielectric which surrounds the pin is provided with a domed protuberance which deflects liquid away from the pin. As a result, there is no surface tension to hold droplets of liquid at the distal end of the connector, and no chance of electrolytic bridging between the conductor pin and the outer body of the connector when the connector extends horizontally through the entry port of a electrical device. In a second embodiment, the dielectric is provided with a tubular extension portion which forms an insulator sheath around the central conductor pin, thus preventing bridging even when the connector is oriented vertically and the distal end of the outer body is submerged in liquid.