IEC 60404-1-1:2004

Establishes a classification of surface insulations for electrical steel sheet, strip and laminations according to their general composition, relative insulating ability and function.
These surface insulations are either oxide layers or applied coatings.
The purpose of this classification is to create a nomenclature for the various types of surface insulations and to assist users of surface insulations by providing general information about the chemical nature and use of the surface insulations.
It is not the intent of this classification to specify insulation requirements in terms of specific values of surface insulation resistance. Such requirements are agreed between the purchaser and the steel producer, where applicable.
The classification is used in conjunction with the various specifications for cold rolled electrical steels (see the standards in the IEC 60404-8 series in Clause 2).