With regard to this and similar posts by John in the past:
Perhaps I and we should have noticed before but, looking at the thread on insulation tape has led me to 'discover' that there is indeed a definition of 'reinforced insulation' in Part 2 - BUT don't expect too much.
The relevant standard presumably is not available without a charge.
As I said, a high proportion of DI-marked (i.e. 'Class II') items appear to have only one layer of insulation, at least in relation to some live parts, so I can but assume that it has somehow been decided/determined that the material of the single layer qualifies as "reinforced" - but, as I also said, I've yet to see a definition!
Perhaps I and we should have noticed before but, looking at the thread on insulation tape has led me to 'discover' that there is indeed a definition of 'reinforced insulation' in Part 2 - BUT don't expect too much.
The relevant standard presumably is not available without a charge.