RCBO WITH FUNCTIONAL EARTH LEAD CAUSING SMALL EARTH LEAKAGE

I suspect that if the device is 'passive', and in a PME (Protective Multiple Earth) style arrangement (incoming side), then it is not the RCBO that creates the leakage, rather it is the natural leakage of all those RFI filters on all the electronic equipment connected to the down stream load.


The RFI devices have the Y capacitor connected such that there are two equal capacitances between Live and Neutral (hence half live volts at the split point, with a Thevenin equivalent capacitance of 2.C [or is that half C]) and, that half live volts, fed through the equivalent capacitance connected to the Earth, creates the leakage (<1.6mA if I remember correctly), and all the 50Hz contributions (all those RFIs) are in phase at the RCBO.


Any filtered harmonics at 3/6/9 (150Hz etc), when spread across 3 phases will then be additive in the neutral, making for a large neutral current (hence all the regulations about level of harmonics in modern electronics..)


If the RCBO itself has active circuitry (rather than just a sensitive relay), then it is also likely to have it's own RFI (depending on how it's powered) to filter the internal power supply. But it's likely to be negligible relative to the external load RFI filters.

I suspect that if the device is 'passive', and in a PME (Protective Multiple Earth) style arrangement (incoming side), then it is not the RCBO that creates the leakage, rather it is the natural leakage of all those RFI filters on all the electronic equipment connected to the down stream load.


The RFI devices have the Y capacitor connected such that there are two equal capacitances between Live and Neutral (hence half live volts at the split point, with a Thevenin equivalent capacitance of 2.C [or is that half C]) and, that half live volts, fed through the equivalent capacitance connected to the Earth, creates the leakage (<1.6mA if I remember correctly), and all the 50Hz contributions (all those RFIs) are in phase at the RCBO.


Any filtered harmonics at 3/6/9 (150Hz etc), when spread across 3 phases will then be additive in the neutral, making for a large neutral current (hence all the regulations about level of harmonics in modern electronics..)


If the RCBO itself has active circuitry (rather than just a sensitive relay), then it is also likely to have it's own RFI (depending on how it's powered) to filter the internal power supply. But it's likely to be negligible relative to the external load RFI filters.