MT 36 - TC 10/MT 36

IEC 61203:2025 This document provides procedures and supervision for the use and maintenance of synthetic esters in transformers and other electrical equipment. This document includes recommendations on tests and evaluation procedures and outlines methods for reconditioning and reclaiming the liquid, when necessary

IEC 61039:2025 establishes the detailed classification of the N family (insulating liquids) that belongs to class L (lubricants, industrial oils and related products) in accordance with ISO 8681 and ISO 6743-99, affecting product categories that include products derived from petroleum processing, synthetic chemical products and synthetic and natural esters.

IEC 62770:2024 describes specifications and test methods for unused natural esters in transformers and similar liquid-immersed electrical equipment in which a liquid is required as an insulating and heat transfer medium. The exposure of natural ester to air leads to deterioration of the insulating liquid. Use of natural esters is therefore restricted to sealed units, or with the conservator tank protected from the contact with atmosphere by a membrane or other suitable system.