This recommended practice provides calculation methods to conservatively evaluate the feasibility for an existing installed dry-type or liquid-filled transformer, to supply nonsinusoidal load currents as a portion of the total load. This recommended practice also provides necessary application information to assist in properly specifying a new transformer expected to carry a load, a portion of which is composed of nonsinusoidal load currents. A number of examples illustrating these methods and calculations are presented. Reference annexes provide a comparison of the document calculations to calculations found in other industry standards. Suggested temperature rise calculation methods are detailed for reference purposes.