and 18 at the hood 12 is effected by means of conventional crimping connectors 21 cable feeds which are not in use but which are available as desired remain closed by means of a break out section or film 25 formed during the production of the hood 12 which section 25 can be broken out when needed the cables provide the connections to sensors to other devices which for example already supply condensed data to apparatus which is to be controlled or regulated to manual entry devices to displays or printing units to portable storages and the like in addition the hood 12 is constructed in such a way that it is held at the wall 11 of the frame 4 by means of a locking connection preferably comprising an arm as shown requiring an inserting and displacing movement a projecting hook 26 which is formed at the hood 12 and comprises a cut out portion 27 serves to secure the locking connection and fastening of the hood 12 at the wall 11 of the housing 1 in the aligned state of the hood 12 the cut out portion 27 is located in the insertion path of and is engaged by the screw 8 the hood 12 is provided with a circumferentially extending seal 28 and is secured simultaneously with the setting and sealing of the screw 8 as can be seen in addition from fig2 a circumferentially extending strip 29 which can also.