This document describes how the concentrations of dissolved gases or free gases can be interpreted to diagnose the condition of oil-filled electrical equipment in service and suggest future action.

This document is applicable to electrical equipment filled with mineral insulating oil and insulated with cellulosic paper or pressboard-based solid insulation. Information about specific types of equipment such as transformers (power, instrument, industrial, railways, distribution), reactors, bushings, switchgear and oil-filled cables is given only as an indication in the application notes.

This document can be applied, but only with caution, to other liquid-solid insulating systems.

In any case, the indications obtained are given only as guidance with resulting action undertaken only with proper engineering judgment.

A Commented Version (CMV) of this standard is available here. Please note, the CMV of the standard is not adopted, and therefore doesn’t contain an additional national foreword, or national annex that might be contained in the BS adoption of the standard. However the IEC text that forms the content of the standard is identical to the BS adoption of the standard.

Commented Versions (CMVs) are specialized publications featuring detailed commentary from technical experts on the major changes between the new edition of a standard and the previous one. Comments may include an explanation for the changes as well as information on the impact of these changes on the application and usability of the standard.