Applies to screw-type and screwless-type clamping units for connecting devices, either as separate entities or as integral parts of equipment, for the connection of electrical copper conductors (complying with IEC 60228), rigid stranded and/or flexible, having a cross-section above 35 mm[2] and up to and including 300 mm[2] and equivalent AWG/kcmil sizes with a rated voltage not exceeding 1000 V a.c. and a frequency up to and including 1000 Hz and 1500 V d.c. It also applies to clamping units primarily suitable for connecting unprepared conductors.