This part of International Standard IEC 60076 applies to three-phase and single-phase power transformers (including auto-transformers) with the exception of certain categories of small and special transformers such as:
single-phase transformers with rated power less than 1 kVA and three-phase transformers less than 5 kVA; transformers, which have no windings with rated voltage higher than 1 000 V; instrument transformers; traction transformers mounted on rolling stock; starting transformers; testing transformers; welding transformers, explosion-proof and mining transformers; transformers for deep water (submerged) applications.
When IEC standards do not exist for such categories of transformers, this part of IEC 60076 may still be applicable either as a whole or in part.