Deals with clamping units of any material for connecting devices, either as separate entities or as integral parts of products, for the connection of aluminium (bare or plated) and copper-clad aluminium conductors (complying with IEC 228), rigid (solid and stranded), having a cross-sectional area of 2,5 mm2 up to and including 50 mm2, with a rated voltage not exceeding 1 000 V a.c. up to and including 1 000 Hz, and 1 500 V d.c. Deals also with aluminium bodied clamping units for the connection of rigid (solid and stranded) and flexible copper conductors (complying with IEC 228), 0,5 mm2 up to and including 35 mm2. Applies not for clamping units for connection by crimping, brazing, soldering or welding.