A high voltage generator (3) is coupled to an X ray tube (4) via a high voltage cable (2). The voltage is applied to the anode (4a), with the cathode (4b) earthed. The high voltage cable (2) has an inner conductor (7) surrounded by a first (8) and second (9) screening. The first screening is connected directly to earth on the X ray tube side and via an overload voltage protection device (5) on the generator side.
