a. Alternative measurements of 1.0 mm (0.04 in) and 2.0 mm (0.08 in), respectively, for gaps.
b. The ppm moisture values shown are based on consensus, which are also given in IEEE Std 637. These values should not be used to infer solid insulation dryness or dielectric integrity. The moisture in oil at a given time cannot be related to insulation moisture caused by nonequilibrium conditions. From a dielectric strength point of view, the moisture in oil limits given could be excessive at low temperatures because of high moisture in oil percent saturation levels. However, in operating units, the same moisture in oil levels might represent low moisture in oil percent saturation levels caused by increased oil temperatures.
c. Any significant changes from previous test data should be investigated.