This International Standard deals with safety aspects of power transformers, power supplies, reactors and similar products such as electrical, thermal and mechanical safety. This standard covers the following types of dry-type transformers, power supplies, including switch mode power supplies, and reactors, the windings of which may be encapsulated or non-encapsulated It has the status of a group safety publication in accordance with IEC Guide 104. The contents of the corrigenda of March 2008, March 2010 and April 2011 have been included in this copy.