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Long shot - anyone have a copy of the WireRegs/Commentary-UpdateApr04.pdf

mapj1
Until a couple of years ago the IET published a 'commentry' that described some tests of cable ageing with over temperature and has formuae for estimated the life shortening effect of  overloading.

The URL used to be
https://www.theiet.org/Publish/WireRegs/Commentary-UpdateApr04.pdf


Sadly the webpage has moved as part of one of the tidy-ups, and for whatever reason the Wayback machine never archived it. Before I pester the webmasters on Monday if they have it on back-up tapes I'd like to ask on the off chance if anyone happens to have kept a copy they could upload ?
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    Whilst this might provide some insight, it cannot in any way be described as definitive. Plasticised PVC is not a single material with constant properties, every stage of its manufacture and processing will change the aging characteristics in unknown ways. It would appear that cracking is not the major failure mechanism, as it is for uPVC, and from samples of cable from the first day that PVC was used, it appears to have a virtually unlimited life as cable sheaths or primary insulation in most installations. UV does cause cable damage after a long period in PVC without suitable blocking pigment, but is usually powdering of the surface, caused by de-polymerisation and breaking of the polymer chains. It takes a very long time for the sheath to disappear and for the primary insulation to be attacked. The main effect of long term heat is probably slow loss of the plasticiser, which makes the cable more rigid, and possibly susceptible to mechanical movement and could cause cracking if the cable is flexed. However this would be unusual in the fixed wiring installation. The best way to check the cables is undoubtedly inspection and perhaps laboratory examination if the application is particularly critical.
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    Whilst this might provide some insight, it cannot in any way be described as definitive. Plasticised PVC is not a single material with constant properties, every stage of its manufacture and processing will change the aging characteristics in unknown ways. It would appear that cracking is not the major failure mechanism, as it is for uPVC, and from samples of cable from the first day that PVC was used, it appears to have a virtually unlimited life as cable sheaths or primary insulation in most installations. UV does cause cable damage after a long period in PVC without suitable blocking pigment, but is usually powdering of the surface, caused by de-polymerisation and breaking of the polymer chains. It takes a very long time for the sheath to disappear and for the primary insulation to be attacked. The main effect of long term heat is probably slow loss of the plasticiser, which makes the cable more rigid, and possibly susceptible to mechanical movement and could cause cracking if the cable is flexed. However this would be unusual in the fixed wiring installation. The best way to check the cables is undoubtedly inspection and perhaps laboratory examination if the application is particularly critical.
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