Insulation classes are defined in DIN EN 60085. An insulation class defines insulation materials (such as enameled copper wire) in terms of their maximum operating temperature. The classes refer to both electrical insulation materials (EIM) and electrical insulation systems (EIS). In electrical engineering, electronic components can reach very high temperatures, which can impair or destroy insulation. The insulation classes are therefore intended to prevent thermal decomposition from destroying the insulating materials during use or rendering them non-functional. The insulation materials are divided into heat classes with different limit temperatures with regard to their heat resistance. These temperatures must not be exceeded permanently during operation in order to guarantee a longer service life.