This part 2-15 of IEC 61558 applies to stationary, single-phase or polyphase, air-cooled (natural or forced) isolating transformers for the supply of group II medical locations, designed to be permanently connected to the fixed wiring of IT supply system. This standard also applies to transformers incorporating electronic circuits. This standard does not apply to external circuits and their components intended to be connected to the input and output terminals or socket-outlets of the transformer. It has the status of a group safety publication in accordance with IEC Guide 104. This part 2 is intended to be used in conjunction with IEC 61558-1.