Abstract: An electrical connecting device is provided. The device comprises a supporting channel having, on one of its lateral faces, a longitudinal slot. The slot permits slidable insertion of at least one electrical connecting component having a selector switch, an electrical receptacle for electrical connection and an adapter which can be inserted inside the supporting channel slot. The adapter is equipped with conductive terminals adapted to enter into contact with conductors located on one or both of the two inside lateral faces of the supporting channel, adjacent to the one which has the lengthwise slot. The adapter is located inside the connecting component in such a way as to be able to pivot on its longitudinal axis to the left or the right from its inserting position when the connecting component is introduced into the supporting channel.