This standard describes electrical and mechanical requirements of liquid-immersed distribution and power transformers, and auto-transformers 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 Revision Standard - Superseded.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 auto-transformers and regulating transformers; single-phase 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.