Is recycled transformer oil safe for reuse in power transformers?

Recycled transformer oil can be safe if properly processed to restore dielectric strength, remove moisture, acids, sludge, and contaminants, and verified through full laboratory testing. Re refined oil must meet the same standards as new oil. PCB contaminated oil is not reusable. Utilities may use reclaimed oil for topping up or less critical units, but many prefer new oil for high voltage assets due to reliability and warranty considerations.