Recent discussions have stimulated me to think about all-RCBO CUs - since we are probably heading for the day (albeit fairly distant) when they will become the norm.
Considering the pros and cons, the 'pros' are fairly clear. The main (fairly massive) 'con' at present is cost, but that may change. The only other one I can think of is the small adverse effect on fault-finding, so long as they don't give an indication of whether they have tripped because of overload or residual current (but even that is at least partially cancelled by making fault-finding easier in some respects).
There will be a few situations (e.g. if there are two or more final circuits with unavoidable appreciable earth leakage) in which all-RCBO is the obvious (maybe the only sensible) way to go. However, more generally ...
.... particularly while cost remains a major issue, I wonder if we are moving in this direction simply "because we can" - i.e. I wonder if (other in the specif situations mentioned above) there really are enough problems (presumably mainly those of 'convenience') associated with not having all-RCBO CUs to justify a widespread change to using them.
Speaking personally about my own electrical installations, I can't really think of any occasion in the last few decades (since I started having RCDs) when not having all-RCBO CUs presented any appreciable problem, or even significant inconvenience.
Kind Regards, John
Considering the pros and cons, the 'pros' are fairly clear. The main (fairly massive) 'con' at present is cost, but that may change. The only other one I can think of is the small adverse effect on fault-finding, so long as they don't give an indication of whether they have tripped because of overload or residual current (but even that is at least partially cancelled by making fault-finding easier in some respects).
There will be a few situations (e.g. if there are two or more final circuits with unavoidable appreciable earth leakage) in which all-RCBO is the obvious (maybe the only sensible) way to go. However, more generally ...
.... particularly while cost remains a major issue, I wonder if we are moving in this direction simply "because we can" - i.e. I wonder if (other in the specif situations mentioned above) there really are enough problems (presumably mainly those of 'convenience') associated with not having all-RCBO CUs to justify a widespread change to using them.
Speaking personally about my own electrical installations, I can't really think of any occasion in the last few decades (since I started having RCDs) when not having all-RCBO CUs presented any appreciable problem, or even significant inconvenience.
Kind Regards, John