BS EN 62770:2014

INTRODUCTION
1 Scope
2 Normative references
3 Terms and definitions
4 Properties, their significance
  and test methods
5 Classification, identification, general
  delivery requirements
  and sampling
Annex A (normative) - Summary of the test
        method for evaluating oxidation
        stability of unused natural esters
Annex B (informative) - Specifications of
        low-viscosity insulating fluids
        derived from natural esters
Bibliography
Annex ZA (normative) - Normative
        references to international
        publications with their
        corresponding European
        publications

Explains specifications and test methods for unused natural esters in transformers and similar oil-impregnated electrical equipment in which a liquid is required as an insulating and heat transfer medium.

IEC 62770:2013 describes specifications and test methods for unused natural esters in transformers and similar oil-impregnated electrical equipment in which a liquid is required as an insulating and heat transfer medium. Natural esters with additives are within the scope of this standard. Because of their different chemical composition, natural esters differ from insulating mineral oils and other insulating fluids that have high fire points, such as synthetic esters or silicone fluids. Natural, ester-derived insulating fluids with low viscosity have been introduced but are not covered by this standard. Pertinent properties of such fluids are given in Annex B. This standard is applicable only to unused natural esters. Reclaimed natural esters and natural esters blended with non-natural esters fluids are beyond the scope of this standard.