Where to position AFDD's in HMO subs

[Jimbo6871]

I've always regarded that as meaning plastered into a wall rather than loose in a cavity. 'Buried' makes little sense otherwise.

Now that's a valid point!
I'd always taken it as a cable in a 100mm wall stud or solid would have to be less than 50mm from one side or other so would need an RCD. It's not something that comes up for me anyway as when I do subs I always use SWA and the RCD / RCBO's are in the sub CU's.