the contact section 40 b in the shape of a segment of a circle where the radius of curvature of the contact section 40 b essentially corresponds to the length r the sliding contact 72 of the annular setting element 73 engages at a contact position 80 on the contact section 40 b in the shape of a segment of a circle in the case of one rotation of the annular setting element 73 the sliding contact 72 moves along the contact section 40 b in the shape of a segment of a circle which results in the possibility of continuously changing the contact position 80 and thus the length of the short circuit device 40 the short circuit connection extends from the conductor 20 via the contact sections 40 a and 40 b the contact position 80 the sliding contact 72 and the setting element 73 to the electrically conductive housing 30 the second short circuit device 50 represented in fig2 has a structure similar to the short circuit device 40 a wire like contact section 50 a is electrically connected to the electrical conductor 20 at a location so that both short circuit devices 40 and 50 lie in the same plane the wire like contact section 50 a again extends perpendicularly away from the electrical conductor 20 a contact section 50 b in the shape of a segment of a circle is.