This specification covers electrically insulating, unbleached sulfate paper and paperboard used as layer insulation in coils, transformers, and other similar apparatus. The materials may also be used as turn insulation, slot liners, wedges, phase insulation, and separator papers in stranded wire/cable constructions. This specification does not include tissue for manufacture of capacitors. Other commonly used terms for the materials include soft coil wrap, dense coil wrap, kraft coil insulation, dry-finished kraft, and water-finished kraft. The materials covered in this specification are classified into four types according to density range and nominal thickness and should conform to the required values of ash content, alcohol-soluble material content, aqueous extract conductivity, water-soluble chloride content, fiber composition, moisture content, hydrogen ion concentration, pH, tensile strength, dielectric breakdown voltage, and conducting paths.

1.1 This specification covers electrical grade unsized, unbleached sulfate paper and paperboard for use as layer insulation in coils, transformers, and similar apparatus. Other applications may include, but are not limited to, turn insulation, slot liners, wedges, phase insulation, and separator papers in stranded wire/cable constructions. Tissue for the manufacture of capacitors is not included in this specification. Other commonly used designations include:

1.1.1 Soft Coil Wrap,

1.1.2 Dense Coil Wrap,

1.1.3 Kraft Coil Insulation,

1.1.4 Dry-Finished Kraft, and

1.1.5 Water-Finished Kraft.

1.2 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard.