Same side of the coin Geoff,
Thre are situations where you cannot isolate the supply to a building, we have a place over the road here that has 145 elderly people in it.
Sure the Fire Station is close, but if a fire broke out in there, it would be a toss up as to who would be worst injured, the Fire Service or the Nurses helping those to get out.
I took the boys through there a year ago and showed them what was in there, on a familiarisation tour.
Myself and SO Cairns tripped the Fire alarm system.
I tripped the Main CB suppling the place.
They both failed, the fire pump never even started. [Linked Image]
Unreal!