- IEC 60296:2012, Fluids for electrotechnical applications – Mineral insulating oils for electrical equipment
- IEC 60422:2024, Mineral insulating oils in electrical equipment – Supervision and maintenance guidance
- IEC 60944:1988, Guide for the maintenance of silicone transformer liquids
- IEC 60666:2010, Detection and determination of specified additives in mineral insulating oils
- IEC 61203:2025, Synthetic organic esters for electrical purposes – Guide for maintenance of transformer esters in equipment
- CIGRE Brochure 413:2010, Insulating Oil Regeneration and Dehalogenation
Given the predominant spread on the market of mineral insulating oils, the reference standards are IEC 60296 and IEC 60422; the former for new mineral insulating oils, the latter for mineral insulating oils in operation.An oil is considered new (unused) as long as it is outside the transformer (or other electrical equipment), i.e. in drums or tanks; in this case, IEC 60296 applies.When the oil is inside the transformer, the liquid is defined as used, in operation, and IEC 60422 applies.
