What is the code for transformer oil used in power transformers?

The code for transformer oil used in power transformers is typically defined by the ASTM D3487 standard, which specifies the requirements for mineral insulating oils. This standard ensures that the transformer oil meets necessary properties such as dielectric strength, viscosity, and chemical stability, which are crucial for the safe and efficient operation of power transformers. Compliance with this code is essential for maintaining transformer performance and longevity.