Unless Hagar are saving money by stocking one spec of tri-rated, and using sleeving as appropriate.
Judging by the length of the functional earths on my RCBOs, and the fact they are using up old black cable in their manufacturer, I'd say you could well be correct that Hager are penny pinching
. This stuff is definately flex-like in its multi-strandedness, and someone above suggested it was tri-rated. Personally I dunno. I'd thought that if it is tri-rated, perhaps that's why it gets away with seeming to be smaller than 25mm, which I was expecting to see given the 100A rating of the CU. Ah well.
Liam
If the neutral wiring is what I have come across, the wire is a bare soft mutlistranded flexible wire, the ends of which are formed and (I think) copper plated to make it a hard piece for termination. The whole thing is put in cloth based & soft plastic covered (could be silicon or latex ish) sleeving rather like the old sistoflex that I have not seen for years.
The live looks like it could be tri-rated and 10mm is commonly supplied by manufacturer for this situation. the ratings are:-
10mm single conductor in free space @ 45' = 75A, 1 sec = 1036A, 5 sec = 483A, bunch of 12 or more = 42A, diameter = 6.4mm
16mm single conductor in free space @ 45' = 100A, 1 sec = 1458A, 5 sec = 741A, bunch of 12 or more = 56A, diameter = 8.2mm
25mm single conductor in free space @ 45' = 136A, 1 sec = 2590A, 5 sec = 1158A, bunch of 12 or more = 77A, diameter = 9.4mm
These figures do vary between cable manufacturers particularly the overall diameter and its not unusual to find a 10mm thats bigger than a 16mm, but these seem typical.
Its not unusual to find tri-rated cables running at currents far higher than those shown without displaying undue stress, where equipment has been uprated but the panel wiring has not.