DIN EN IEC 60422:2025-12

This document provides monitoring guidance and procedures that are required for the use and maintenance of mineral insulating oils and other hydrocarbon-based liquids in transformers and other electrical equipment, including strategic spares and tanks for holding spare parts and components. This document is also intended to assist the power equipment operator to evaluate the condition of the oil and maintain it in a serviceable condition. It also provides a common basis for the preparation of more specific and complete local codes of practice. The document includes recommendations on tests and evaluation procedures, and outlines methods for reconditioning and reclaiming oil, and the decontamination of oil contaminated with PCBs. This document is applicable to mineral insulating oils, originally supplied conforming to IEC 60296, in transformers, switchgear and other electrical apparatus where oil sampling is reasonably practicable, and where the normal operating conditions specified in the equipment specifications apply. This document contains no specific restrictions. The standard differs from DIN EN 60422 (VDE 0370-2):2013-11 as follows: a) as a major revision of the fourth edition this new edition of the document has been updated to reflect the latest developments in monitoring the oil condition. New interpretation tables have been prepared and include limit values for specific oil parameters according to system type, along with recommended corrective measures in the tables and the new test methods; b) the limits of measures for all oil tests have been revised, and changes have been made where necessary in order to make it possible for users to utilize current technology and meet requirements and regulations with regard to safety and aspects involving environmental protection; c) category O has been removed and is now included in category A; d) online moisture evaluation has now been included; e) additional guidance on oil treatment (including criteria for regeneration) is now available; f) the guidance on corrosive sulfur has been updated; g) in addition, this document incorporates changes introduced in related standards since publication of the fourth edition.