Applies to screw-type and screwless-type clamping units of any material for connecting devices, either as separate entities or as integral parts of products, for the connection of unprepared electrical aluminium (bare or plated) and copper-clad aluminium conductors (complying with IEC 60228), rigid (solid and stranded), having a cross-sectional area of 2,5 square millimeters up to and including 50 square millimeters. Has the status of a group safety publication in accordance with IEC Guide 104.