My builder and I are trying to figure out if an outdoor recessed mains light fitting needs to have an IP rating. The thing is the standard says recessed fittings with all wiring inside the ceiling is excluded, but if installed less than 3m above zone 1 or zone 2 (e.g. the zones next to and near a bath, shower, spa, pool, water feature, etc.) then it needs to be IPx4. So what if the recessed fitting is installed in the soffit? It is inside the ceiling space, but it is outside and it is also essentially a wet area. We cannot find the answer in AS/NZS 3000:2000 A3 (2003), and the electrician seems to not be bothered to find out or look in the latest standard until I can point hit to a clause. Google only comes up with results for insulation.
The "enhanced Protection" against electric shock as laid out in Section 6 of AS/NZS 3000:2007 covers the specific damp areas mentioned in that section (Such as Bathrooms, Pools etc)
However refer to this clause: 6.1.2 (b) "...Provide adequate protection against damage that might reasonably be expected from the presence of water or high humidity"
In this case we have a "fit-for-purpose" clause rather than a safety one (unusual in AS/NZS 3000)
Now the important part here is humidity. One could easily expect an outside area to be 'humid' especially in winter. Therefore an IP rated fitting is appropriate for this area to ensure protection against damage.
Whilst this isn't necessarily a safety consideration, it is included in AS/NZS 3000 and as such could be enforced were it to be interpreted this way.
This is my best take on things, as the specific issue isn't addressed per se, however the fit for use clause seems designed to cover these gray areas.