I think you'll have a hard time convincing anyone that's an improvement. People seem to love diversity and isolation in their circuits. How does the cost compare to individual breakers (if you have them) and how many breakers go on one RCD?
Here, Homeline breakers are about $5 each, 1-pole *FCI breakers are about $40 each and 2-pole *FCI are $85.
Is arc fault a thing over there, and does the RCD provide that?
The point I was trying to make is if you tie 5 circuits to one RCD, if it trips you know, you don't get the spoiled freezer problem because you didn't notice. You reset and if it goes again turn that bank of breakers off, reset again and individually turn on breakers until you find the faulty circuit.
You would get 5 or 6 breakers per RCD in an average consumer unit, you would only have 2 RCD's in there.
Decent makes, not the cheapest rubbish,
A breaker is about £4
An double pole RCD (to feed breakers) is about £40
An individual RCD breaker (RCBO) is about £40
An arc fault, RCD breaker (RCBO + AFDD) is about £200 you don't see them very often, they also take up 2 modules in the unit, a big unit here is 18 or 21 modules.
But it has to be said the way we actually do our wiring, we don't tend to have many arc issues, outlets, switches connections are screwed, no wire nuts, no routine pigtails in boxes, no aluminium wire was used consumer side of the meter.
Domestic electrical fires that aren't caused by appliances are quite rare.
Electricians also have to test the operation of the RCD's, and various other things with the very expensive test boxes they have to make sure everything is correctly wired and working properly. You are also not allowed to do electrical work as a homeowner beyond some very basic things anymore, so almost all work "should" be done (and then tested and certificated) by a qualified person.
!! So you could run maybe 50+' of unprotected (no fuse/breaker) 200A wire !! Imagine if a worker hit that with a back hoe. I would stay HOT until the wire melted !!
