Which IEC or ASTM transformer oil standards are commonly applied?

Commonly applied standards include IEC 60296 for unused and reclaimed mineral insulating oils, IEC 60156 for dielectric breakdown voltage testing, IEC 60567 for DGA sampling and analysis, and IEC 60599 for DGA interpretation. On the ASTM side, ASTM D3487 defines mineral insulating oil specifications, ASTM D1816 and D877 address breakdown voltage testing, and ASTM D3612 covers dissolved gas analysis. Utilities select standards based on regional practice, asset class, and regulatory requirements, often combining IEC and ASTM references in specifications.