The following topics are dealt with: temperature classification; insulating materials; insulation systems; temperature measurement; and equipment rating.

These principles are intended to serve as a guide in the preparation of AIEE and other Standards which deal with the selection of temperature limits and the measurement of temperature for specific types of electric equipment. They include an outline of the fundamental considerations which determine the selection of temperature limits, appropriate methods of temperature measurement, and a discussion of the factors to be considered in applying the principles to specific cases. Guiding principles are also included for the development of Test Procedures for the thermal evaluation and classification of electrical insulating materials and of insulation systems for use in electric equipment. Insulating materials, as referred to herein, include processed compositions of raw materials and simple combinations thereof before they are fabricated into coils or other structures identified with specific parts of electric equipment. Insulation systems, as referred to herein, include fabricated and processed combinations of insulating materials with the associated parts of electric equipment. Such equipment may contain more than one insulation system.