New single module AFDD RCBO

I would be interested in forum members views on whether AFDD protection is needed on 30mA RCD protected circuits where the CPC is in close contact with the insulation on the live conductors such as T &E and FP200 cables? Would not the 30mA RCD operate far in advance of an AFDD if there was thermal damage to the conductor insulation?

T&E and thermal damage, I'd agree that the chances are that the RCD would trip.


With mechanical damage though - e.g. screw or nail (esp if later partially removed) clipping the side of the cable and damaging one of the outer conductors alone - possibly less likely.


Likewise for (loose) connections made in insulating enclosures.


If would have thought that 'all round' earthing - e.g, BS 8436 cables and metal-clad accessories would have been a more reliable in that respect. Probably need all class I appliances then too though.


  - Andy.

I would be interested in forum members views on whether AFDD protection is needed on 30mA RCD protected circuits where the CPC is in close contact with the insulation on the live conductors such as T &E and FP200 cables? Would not the 30mA RCD operate far in advance of an AFDD if there was thermal damage to the conductor insulation?

T&E and thermal damage, I'd agree that the chances are that the RCD would trip.


With mechanical damage though - e.g. screw or nail (esp if later partially removed) clipping the side of the cable and damaging one of the outer conductors alone - possibly less likely.


Likewise for (loose) connections made in insulating enclosures.


If would have thought that 'all round' earthing - e.g, BS 8436 cables and metal-clad accessories would have been a more reliable in that respect. Probably need all class I appliances then too though.


  - Andy.