The invention relates to the earthing of an electronic circuit in a device belonging to a low-voltage system with 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, as well as to the overvoltage protection of the interface between such an electronic circuit and a SELV (Safety Extra Low Voltage) circuit. 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 (Ub) of the overvoltage protector is higher than the voltage present across it in normal operating conditions but lower than the minimum dielectric strength (Uc) of the component forming the interface between the electronic device and the SELV circuit.