scope:

This guide covers general recommendations for the loading of dry-type distribution and power transformers that have 80 °C, 115 °C, and 150 °C average winding rises and insulation systems limited to 150 °C, 180 °C, and 220 °C maximum hottest-spot operating temperatures, respectively. The guide includes recommendations for ventilated, nonventilated, and sealed dry-type transformers having impregnated insulation systems. For more specific recommendations for a particular transformer, the manufacturer of that transformer should be consulted.