Abstract: A connector which is intended for the connection of a line without prior removal of its insulating case includes a base in which a contact pressure member carrying a contact element is disposed. The connector also includes a counterpressure member such that between the contact pressure member and the counterpressure member, a conductor which is to be connected, can be held. The force for transferring the contact pressure and counterpressure members into a clamping position is transmitted by a adjustment spring which has its travel determined by a stop and this stop therefore regulates the subsequent transfer of force. A centering and constricting device includes side pieces formed partly by the counterpressure member which when the connector is moved into its clamping position, center the conductor on the contact element and press together as a result of forces which are directed at least approximately towards the longitudinal axis of the conductor.