This current International Standard now differentiates between thermal classes for both electrical insulation systems and electrical insulating materials. It sets forth the criteria for assessing the thermal durability of either electrical insulating materials (EIM) or electrical insulation systems (EIS). Additionally, it outlines the process for designating thermal classes.
The standard is to be applied when the thermal factor is the primary cause of aging.
Note: A thermal class is not designated for an EIM in relation to its application within an EIS.
