Applicable to cable reels for a.c. only, supplied with a non-detachable flexible cable having a rated voltage over 50 V, not in excess of 250 V for single-phase cable reels and over 50 V and not in excess of 440 V for all other cable reels, and a rated current not in excess of 16 A, for use in household, commercial and light industrial and similar situations, in- or out-of-doors, referring especially to safety in normal use.