So the isolation is outside the room where the equipment is, would the worker be in control of this switch? hard when its not in the same room, if not is it lockable?
If you want less accessories you could always fit a fan that doesnt require 3A fuse and use the devices in the fuseboard for isolation, 7671 happy, manuf instructions complied with. there will be some that claim you need local isolation for non skilled workers to maintain fan, how many people actually maintain fans and does it say in the manuf instructions that only qualified personnel to work on fan? if you cant lock off and prove dead i dont think you should be working on it.
there is also the 'need light when working on fan' argument although i have no idea where it comes from and holds no water with me.
Are not all "isolation switches" situated outside typical sized bathrooms both in domestic and commercial situations?