ANSI-C57.12.20 Complete Document History
Transformers - Standard for Overhead Type Distribution Transformers, 500 Kva and Smaller

Complete Current Edition:
   2023 EDITION - Overhead-Type Distribution Transformers 500 kVA and Smaller; High Voltage, 34 500 V and Below; Low Voltage, 7970/13 800Y V and Below - Sept. 21, 2023

Obsolete Revision Information:
   2005 EDITION - HIGH VOLTAGE, 34500 VOLTS & BEYOND - Jan. 1, 2005
   1997 EDITION - HIGH VOLTAGE, 34500 VOLTS & BE - Jan. 1, 1997
   1994 EDITION - TRANSFORMERS - OVERHEAD - TYPE - Jan. 1, 1994
   1988 EDITION - TRANSFORMERS - OVERHEAD - TYPE - Jan. 1, 1988