Aland - without looking at the Merlin or []D cats, I can't see a suitably rated contactor fitting in there; they are rated at 80 -100A in line with the disconnect...

Paul, many commercial outfits, and such as churches/halls use non-essential shunts as added protection. You're guaranteed that everything is turned off, and that if someone enters/breaks into the building nothing will be switched/left on. It's generally buildings that are empty at night, or for longer periods. Some hotels/etc. also use them to be sure everything is turned off ( eg in the kitchen ) without having to go round and visual the whole place.

I guess a paranoid houseowner ( whos house maybe burned down previously through electrical fault ) might want to go that route... [Linked Image]

If hindsight were foresight, we'd all be millionaires!