What does BS 148 specify for transformer oil standards?

BS 148 is a British Standard that specifies requirements for recycled mineral insulating oils used in transformers and electrical equipment. It defines quality parameters, test methods, and acceptance criteria for reclaimed oil, ensuring it is fit for reuse. The standard addresses dielectric strength, moisture, acidity, contaminants, and general condition. BS 148 is typically applied when recycled oil is supplied instead of unused oil and is referenced in procurement, acceptance testing, and quality control procedures.