What common names are used for transformer oil?

Common names include mineral insulating oil, transformer insulating oil, dielectric oil, and transformer mineral oil. In utility and industrial catalogs you will also see terms like naphthenic transformer oil (a common mineral-oil base stock type) and inhibited transformer oil (mineral oil with oxidation inhibitor). For higher fire safety or environmental needs, suppliers market natural ester fluid (for example FR3 type fluids) and synthetic ester or silicone insulating liquid. IEC 60296 is often referenced for mineral oils in transformers.