Only ever came across the stuff once on a EICR first test I did was IR all <1M. What dates were lead cables anyone? Never come across the stuff in service?
theres something in 621.3 GN3 archy...
oh would it now?
i think not....
see as it would have been as a result of your investigations that the insulation `fell apart`...then you would have a duty of care to make a repair....even if only temporary....
as you also have a duty of care to leave the occupants with adequate power for lighting and outlets....
I have seen the stuff fall apart in your hands.