GB/T 11021-2014 Specifies the heat resistance and representation method of electrical insulation. It defines the terms related to electrical insulation heat resistance, introduces the principles and methods of heat resistance evaluation, and covers the consideration of the performance of different insulating materials in various temperature environments. At the same time, it clarifies the expression of the insulation heat resistance grade, and corresponds the heat resistance to the specific grade label. The standard provides a key basis for the design of the insulation system of electrical equipment, the selection of materials and the control of the mass of products, which helps to ensure the safe and reliable operation of electrical equipment under different temperature conditions, and promotes the development of standardization in the electrical industry.