This part of IEC 60044 applies to newly manufactured combined transformers for use with electrical measuring instruments and electrical protective devices at frequencies from 15 Hz to 100 Hz. The requirements and tests of this standard, in addition to the requirements and tests of IEC 60044-1, IEC 60044-2 and IEC/PAS 60044-5 cover current, voltage and capacitor voltage transformers, that are necessary for combined instrument transformers.