New IEEE Standard - Superseded. Superseded. 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, 185°C, and 220°C maximum hottest-spot operating temperatures, respectively. Transformers through 10 000 kVA are included. Recommendations for ventilated, nonventilated, and sealed dry-type transformers having impregnated insulation systems are provided.