Provides guidance on the acceptable limits of voltage fluctuations at the point of common coupling caused by industrial equipment supplied from high or low voltage electricity supply systems. It applies to all electrical equipment other than that covered by Part 3 of this Standard and in particular it is intended to apply to equipment which is intended exclusively for industrial, professional or commercial purposes and with ratings greater than 3.6 kV.A and which produces changes in the range of one change per day to 1800 changes per minute.