scope:

This Guideline applies to three-phase dry-type transformers subjected to harmonics current up to the 49th harmonic. 

This Guideline covers transformers, self-contained units or components of larger assemblies, 60 Hz, ANN, rated 15 to 500 kVA three-phase, two winding low voltage distribution transformers with maximum winding voltage of 1.2 kV. 

The principles covered in this Guideline may be applied to other transformers, not covered in this Guideline, with due consideration of any special situation or application. 

This Guideline contains no requirements. In this Guideline, "should" is used to express a recommendation or that which is advised and "may" is used to express an option or that which is permissible within the limits of the Guideline.