Superseded by IEEE Std C57.12.20-2005.This standard covers certain electrical, dimensional, and mechanical characteristics and takes into consideration certain safety features of single- and three-phase, 60-Hz, mineral-oil-immersed, self-cooled, overhead-type distribution transformers 500 kVA and smaller, with high voltages 34500 volts and below and low voltages 7970/13800Y volts and below. Such transformers may include one or more of the following features: 1) High-voltage, overcurrent protection; 2) High-voltage, overvoltage protection. 3) Low-voltage, overcurrent protection; 4) Low-voltage, overvoltage protection