An earthing of an electronic circuit is disclosed in a device belonging to a low-voltage system with, for example, a maximum AC voltage of 1000 V or a maximum DC voltage of 1500 V in which the device is at the main voltage potential or is connected to the main voltage through a high-impedance coupling. An overvoltage protection of the interface between such an electronic circuit and a SELV (Safety Extra Low Voltage) circuit is also disclosed. The neutral point (COM) of the electronic device is coupled to protective earth (PE) through at least one breakdown-based overvoltage protector. The rated breakdown voltage of the overvoltage protector is higher than the voltage present across it in normal operating conditions but lower than the minimum dielectric strength of the component forming the interface between the electronic device and the SELV circuit.