This test procedure for the thermal evaluation of insulation systems of dry-type power and distibution transformers is to be used for determining the temperature classification and modification of the insulation systems. This standard shall apply to all dry-type transformers with a voltage of 601 V or higher in the highest voltage winding except as follows:
a) Instrument transformers
b) Step- and induction-voltage regulators
c) Arc-furnace transformers
d) Rectifer transformers
e) Specialty and general-purpose transformers
f) Mine transformers
g) Testing transformers
h) Welding transformers
