<p>The global trend of rising electricity consumption underscores the importance of measuring large currents, and measurement results must be traceable to meet legal metrology requirements. This research aims to provide metrological traceability in the dissemination of the alternating current unit, considering the scale factor of instrument current transformers. The calibration and measurement capabilities declared in the KCDB of the International Bureau of Weights and Measures (BIPM) include characterization of ammeters, thermal current converters, and shunts in the current range up to 100 A, as well as current transformers from units of amperes to tens of kiloamperes. Today, measurement results obtained with current transformers are considered linked to those reproduced by national standards of alternating current scale factors, associated with the turns ratio of primary and secondary windings. One of the main metrological characteristics of current transformers is the ratio error, which is usually determined through calibration and, consequently, relates to the reference ratio error known with the lowest measurement uncertainty. Considering the ratio error as a non-SI quantity, the authors propose an alternative approach to the characterization of current transformers, clarifying the aspects of traceability establishment through the use of precision thermal converters and current shunts, and creating a clear link to SI units. The connection to electrical quantities such as DC voltage, DC resistance, capacitance, and inductance is analyzed and established through a current transformer calibration by a measurement setup with AC/DC transfer for a new purpose. Theoretical notes and analyses of relationships among the main elements of a measurement setup are also presented, along with a newly derived mathematical model and uncertainty budget. Overall, a traceability diagram for high alternating current measurements using a current transformer to SI units is provided based on the outlined approach.</p>