IEC 61558-2-10:2014 deals with the safety of separating transformers with high insulation level and separating transformers with output voltages exceeding 1 000 V. Transformers incorporating electronic circuits are also covered by this standard. This first edition cancels and replaces Chapter ll Section Three of IEC 60989 published in 1991. It constitutes a technical revision. The main changes consist of a) updating this part in accordance with IEC 61558-1:2005, and b) adding power supply units to the scope. 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. The transitional period is not longer than 3 years after the publication of this standard.