However, there are exceptions to these specifications which, for example, relate to damp rooms and comprise half of the specified values.
A distinction is therefore made between safety extra-low voltages, protective extra-low voltages and functional extra-low voltages. As for the safety extra-low voltages, Protective Extra Low Voltage (PELV), this is also called extra- low voltage with safe disconnection and provides protection against electric shock just like the functional extra-low voltage. In this protection class, grounded and ungrounded circuits are permitted. Enclosures can be grounded or connected to a protective earth conductor.