Standardization in the field of power transformers, tap-changers and reactors for use in power generation, transmission and distribution. Generally these transformers have power ratings above 1 kVA single phase and 5 kVA polyphase with a higher voltage winding of 1000 V or more, however the scope includes lower voltage transformers and regulators used in power delivery applications.

Excluded:

- Instrument transformers

- Testing transformers

- Traction transformers mounted on rolling stock

- Welding transformers

- Transformers for applications covered by TC 96.