NEMA C57.12.23
NEMA C571223 1992-JAN-01 Transformers - Underground-Type Self-Cooled Sngle-Phase Dstrbuton Transformers wth Separable nsulated Hgh-Voltage Connectors Hgh Voltage 24 940 Grd Y14 400 V and Below and Low Voltage 240120 V 167 kVA and Smaller-Now Copyrght by EEE