Overview
IEC 61628-1:1997, titled Corrugated pressboard and presspaper for electrical purposes – Part 1: Definitions, designations and general requirements, is an international standard developed by the International Electrotechnical Commission (IEC). This standard provides a comprehensive framework for the definitions, identification codes, and general requirements for corrugated pressboard and presspaper used primarily in electrical insulation applications. The guidelines ensure consistent performance and quality of these materials for manufacturers, engineers, and users in the electrical industry.
Key Topics
- Definitions and Terminology:
- Establishes key terms such as “corrugation” (regular repeated deviation from flatness over the entire sheet), and categorizes types of corrugation by shape and symmetry.
- Corrugation Types:
- Sine (sinusoidal) and angular patterns
- Symmetrical and non-symmetrical forms
- Four possible combinations for precise specification
- Designation System:
- Unique code indicating base material (as specified in IEC 60641-1), thickness, and corrugation type; e.g., B3.1/1/SS (where SS stands for symmetrical sine).
- Material Composition:
- Requires materials to be manufactured from specified pressboard or presspaper without additives, shaped by mechanical pressure, heat, or moisture.
- General Supply Conditions:
- Stipulates adequate packaging for protection throughout handling and transit.
- Marking and Identification:
- Requires legible, standardized identification codes on delivery
- Mandates use of marking materials that are electrically neutral, oil resistant, and non-polluting
Applications
Corrugated pressboard and presspaper specified by IEC 61628-1 are predominantly used as electrical insulation in high-voltage equipment such as transformers, reactors, and related apparatus. Their structured corrugation provides mechanical flexibility, space for oil circulation or ventilation, and enhanced dielectric properties. While insulation is the main application, the material’s unique properties may also be suitable for other uses where mechanical robustness and chemical stability are required.
Typical application areas include:
- Power and distribution transformers
- Electrical reactors
- High-voltage switchgear
- Custom electrical insulation solutions
- Potential use in environments requiring strong, oil-resistant, and stable insulating materials
Related Standards
IEC 61628-1 references and complements several other IEC standards, ensuring a harmonized approach within electrical insulation materials:
- IEC 60641 Series:
- IEC 60641-1: Definitions and general requirements for pressboard and presspaper for electrical purposes
- IEC 60641-2: Methods of test for these materials
- IEC 60641-3-1 and 60641-3-2: Specifications for individual material types (both pressboard and presspaper)
- Additional references:
These standards ensure consistency and interoperability in the electrical industry globally, aiding specification, procurement, and quality assurance processes for insulating materials.
Practical Value
Adhering to IEC 61628-1 ensures that corrugated pressboard and presspaper materials are defined, marked, and supplied according to internationally recognized criteria. This reduces ambiguity in procurement, supports regulatory compliance, and enhances reliability in critical electrical infrastructure projects. Manufacturers benefit from clear production and marking requirements, while users and engineers gain increased confidence in material suitability and performance for demanding electrical insulation applications.