From time to time there is mention in uk.d-i-y on routinely replacing
PVC T&E wiring on the basis of its age, and I need to decide whether
to replace mine. In attempting to make this judgement on an informed
basis, I have isolated, meggered and accurately measured the
continuity of my individual ring final circuits (both statically and
as a source impedance measurement), and all is satisfactory. I have
also removed a 3 metre section , sliced it open and given it a close
visual inspection. It looks virtually brand new, apart from surface
dirt on the outer sheathing. Specifically, there is no visual sign of
any degradation in the PVC insulation.
I have owned the house since it was built, in 1965, and I know that
the wiring has never been subject to overloads ( and in any case the
correct fuse wire has always been used). The wiring has remained
virtually undisturbed so I also know that the cable has not been
subject to any undue mechanical stress.
So although the cable is 40 years old, my conclusion is that it would
be a waste of time replacing it, even though the cost of doing so
would be irrelevant.
Can anyone come up with a technical justification for replacing such
cable purely on the basis that it is time-expired?

CRB