Contains the definitions related to, and the general requirements to be fulfilled by, industrial rigid laminated sheets for electrical purposes, made with any of the following resins as the binder: epoxy (epoxide), melamine, phenolic, polyimide, silicone and unsaturated polyester. The following reinforcements may be used either singly or in combination; cellulosic paper, cotton cloth, glass cloth, glass roving, glass mat, polyester cloth and wood veneers. Materials which conform to this specification meet established levels of performance. However, the selection of a material by a user for a specific application should be based on the actual requirements necessary for adequate performance in that application and not based on this specification alone. The major changes from the previous edition of IEC 60893-1 are the following: a) new material types have been included; b) changes have been made to the property requirements of some existing types; c) a new method for testing permittivity and dissipation factor has been added; d) all non-specification data for each type has been moved to a new Part 4 of IEC 60893.