Overview
IEC 60371-3-2:2005 specifies requirements for mica paper used as electrical insulating materials and intended for processing into built-up mica products (rigid flat mica, flexible mica, curable flexible mica and shaped pieces). This second edition (2005) replaces the 1991 edition and aligns the mica paper specification with updates in IEC 60371-2 (methods of test). The standard sets classification, delivery, marking and test requirements to ensure reproducible performance of mica-based electrical insulating materials.
Key topics and requirements
- Scope and purpose: Requirements for mica paper used in built-up insulating materials for electrical equipment; users must verify material suitability for their specific application.
- Classification & designation: Mica papers are designated MPM (muscovite) or MPP (phlogopite) and grouped into four classes (e.g., MPM class 1–3, MPP class 4). Example designation: MPM-1050 (class 1, 50 g/m²).
- Forms of delivery & marking: Supplied in rolls or sheets; rolls must be wound to avoid telescoping. Marking must include manufacturer, batch/roll number, designation and net mass.
- Quality & handling: Sheets/rolls must be flat, smooth and free from defects, contamination and splices. Packaging to protect during transport and storage is required.
- Test methods & properties (referenced standards used):
- Sampling & specimen preparation: Specific sample sizes and preparation rules (remove outer layers from rolls; cut to represent full width; die cutting preferred).
Applications and who uses it
- Practical applications: Specification is used for mica paper that becomes built-up mica insulation in electrical equipment such as rotating machines, transformers, high-voltage assemblies and other components requiring high-temperature and dielectric stability.
- Primary users: mica paper manufacturers, material suppliers, OEMs (electrical equipment designers), procurement/specification engineers, test laboratories and certification bodies.
- Value: Helps ensure consistent electrical insulating materials, supports material selection, procurement contracts and compliance with agreed performance criteria.
Related standards
Keywords: electrical insulating materials, mica paper, IEC 60371-3-2, mica insulation, mica paper specification.