An electrical connector device comprises a disc-like connector element having a hole therethrough. From a face thereof substantially hard contact means projects outwardly, in the form of an annular ridge which tapers outwardly to a sharp or rounded edge and which is concentric to the hole and radially spaced therefrom. An elastically deformable sealing element overlies said face of the connector element and, in the unused device, embeds the contact means. Tightening of a screw through the hole, to secure the device to an object member, forces the contact means through the sealing element and partway into the object member. The annular electrical connection thus formed is durably sealed by the compressed sealing member.