Protection class I and protection class II
All electrically conductive casing parts must be connected to the protective conductor system for protection class I, which is located on the earth potential. Devices designed for independent operation must feature a mechanical cable grip for the power supply cable.
Devices in protection class II feature double or reinforced insulation between the mains power circuit and the output side or the metal casing. If a cable with a protective earth conductor is used, this must not be connected to the casing.
