falling foul of 'maintenance free' derating

Just musing...


I'm probably (as usual) playing catch up, but today I learned that these Wago and other types (with Hager/Ashley MF boxes aside it seems as they do the job whatever I'm told) have a 'maintenance free' installation clause in that, they can be used to the  'full rating' if accessible, but if installed 'maintenance free' and to comply with BS5733,  the current carrying capacity must be derated; quite significantly it seemed to me re:Ideal In-sure offerings. I hadn't realised this.


I found it difficult looking at the 'instructions' to interpret whether it is possible to use one for example, to join some t&e 2.5 ring final conductors protected by a 32A device and it would seem not...but then again, with all the 'aggregate current' splurb, I started to shutdown :-)


Seems daft to me.  If the box is accessible then no fuss, but make it inaccessible and it cant be done !  Bizarre from an electrical point of view to me that is.


I am awaiting some confirmation from Ideal (as their derating figures seem worse than others) on this subject to get a better understanding why and just in case I've misunderstood (likely! )