Gives the requirements for the compatibility levels for industrial and non-public networks. These levels are relevant to disturbances that may occur in the electrical power supply in normal operating conditions. This standard applies to low voltage and medium voltage a.c. power supply at 50 Hz/60 Hz. Networks for ships, aircraft, off-shore platforms and railways are out of its scope. The contents of the corrigendum of August 1994 have been included in this copy.