IEC 61558-2-14:2012 deals with safety of variable transformers for general applications and power supply units incorporating variable transformers for general applications. Transformers incorporating electronic circuits are also covered by this standard. This first edition cancels and replaces the chapter IV of the IEC 60989 published in 1991. It is a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) update of the existing text; b) complete editorial review. This part has the status of a group safety publication in accordance with IEC Guide 104:2010. The preparation of safety publications and the use of basic safety publications and group safety publications. The attention of National Committees is drawn to the fact that equipment manufacturers and testing organizations may need a transitional period following publication of a new, amended or revised IEC publication in which to make products in accordance with the new requirements and to equip themselves for conducting new or revised tests. It is the recommendation of the committee that the content of this publication be adopted for implementation nationally not earlier than 12 months from the date of publication.