AS 2768-1985

1 - AS 2768-1985 ELECTRICAL INSULATING MATERIALS-EVALUATION AND CLASSIFICATION BASED ON THERMAL ENDURANCE
4 - PREFACE
5 - CONTENTS
6 - 1 SCOPE.
6 - 2 REFERENCED DOCUMENTS.
6 - 3 DEFINITION.
6 - 4 GENERAL.
6 - 4.1 Ageing factors.
6 - 4.2 Classification
6 - 4.2.1 General
6 - 4.2.2 Operating conditions.
7 - 4.2.3 Insulating materials in insulation systems.
7 - 4.2.4 Temperature and temperature rise.
7 - 4.2.5 Other factors of influence.
7 - 4.2.6 Performance of insulating materials.
7 - 4.3 Responsibility for selection and assignment.
7 - 5 THERMAL EVALUATION OF INSULATING MATERIALS.
8 - 6 THERMAL EVALUATION OF INSULATION SYSTEMS
8 - 7 CLASSIFICATION.

Specifies a numerical system of classifying materials and systems based on their thermal endurance, ranging from Class 90 to Class 250 (in nine steps) thereafter in steps of 25, the figure indicating the assigned Celsius temperature. Retains the AS C320 alphabetical classifications Y, A, E, B, F and H (but not C) as an alternative for the time being. Describes the evaluation of long-term thermal properties of materials and of more complex insulation systems, and the influence of service conditions. Also defines the responsibility for assigning thermal identification and classification. Is based on, but differs from IEC 85 (1984) which specifies a part-alphabetical part-numerical system of classification and which permits alternative systems of identification of materials used in certain products.

This standard describes a well-recognized system for the classification of materials for the electrical insulation of electrotechnical products based on their thermal endurance. It considers the thermal evaluation of insulatingmaterials, of insulation systems, their inter-relationship, and the influence of service conditions, and defines the responsibility for assigning a thermal classification to a particular insulating material.