Applies to the classification of degrees of protection provided by enclosures for electrical equipment with a rated voltage not exceeding 72,5 kV. Has the status of a basic safety publication in accordance with IEC Guide 104. The contents of the corrigenda of January 2003, of September 2007 and of October 2009 have been included in this copy. This consolidated version consists of the second edition (1989) and its amendment 1 (1999). Therefore, no need to order amendment in addition to this publication.