Consists of a rotatable upper part with an integrated inner sleeve, a grippy cylindrical outer surface, and a metric connection thread with a hexagonal collar. The protective tube screwed into the upper part is securely held in place against vibration and tension in the connection and meets the requirements of VDE 0100 and 0113. The smooth inner surfaces ensure damage-free cable installation. In practice, the independent rotation capability of the upper part is necessary when the connection is to be pre-assembled without a tube.