This standard describes electrical and mechanical requirements of liquid-immersed distribution and power transformers, and autotransformers and regulating transformers, single-phase and polyphase, with voltages of 601 V or higher in the highest voltage winding. This standard applies to all liquid-immersed distribution, power, and regulating transformers that do not belong to the following types of apparatus: a) Instrument transformers b) Step voltage and induction voltage regulators c) Arc furnace transformers d) Rectifier transformers e) Specialty transformers f) Grounding transformers g) Mobile transformers h) Mine transformers This standard is a basis for the establishment of performance, and limited electrical and mechanical interchangeability requirements of the equipment are described. It is also a basis for assistance in the proper selection of such equipment. Revision Standard - Superseded. Electrical and mechanical requirements for liquid-immersed distribution and power transformers, and autotransformers and regulating transformers; single- and polyphase, with voltages of 601 V or higher in the highest voltage winding, are set forth. This standard is a basis for the establishment of performance, and limited electrical and mechanical interchangeability requirements of equipment are described; it is also a basis for assistance in the proper selection of such equipment. The requirements in this standard apply to all liquid-immersed distribution, power, and regulating transformers except the following: instrument transformers, step voltage and induction voltage regulators, arc furnace transformers, rectifier transformers, specialty transformers, grounding transformers, mobile transformers, and mine transformers.