Cathode block with a groove of varying depth and a fixing device

A cathode block for aluminum electrolysis cell based on carbon and / or graphite has at least one extending in the longitudinal direction of the cathode block groove for receiving at least one bus bar, wherein at least one, seen at least one groove has a over the length of the cathode block, varying has depth, in which the at least one groove with a varying depth limiting wall of the cathode block is provided at least one recess, which extends horizontally in the longitudinal direction of the cathode block. According to another embodiment, a cathode block for an aluminum electrolytic cell based on carbon and / or graphite, at least extending in the longitudinal direction of the cathode block groove for receiving at least a bus bar, wherein at least one of the at least one groove is a the length of the cathode block seen having varying depth, said groove is bounded by a wall, wherein the wall is at least one into the groove extending projection provided.