We are usually referred to as the fire resistant cables tape is divided into epoxy insulation board 3240 insulation board FR-4 insulation board each product of different models of their different grades, we said the insulation board is divided into several grades refers to Insulation board insulation temperature, insulating material insulation and temperature are closely related. The higher the temperature, the worse the insulating properties of the insulating material. To ensure the bakelite electrical insulation board strength, each insulation material has a suitable maximum allowable operating temperature, below this temperature, can be used for long-term safety, more than this temperature will quickly aging. According to the degree of heat, the insulation material is divided into Y, A, E, B, F, H, C and other levels. For example, the maximum allowable operating temperature of Class A insulation is 105 ℃. Generally, the distribution transformer and the insulating material in the motor are mostly A grade, such as epoxy resin insulation board and so on.