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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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    This sort of consideration Mike?


    "Has some tables that suggest that at full all day loading, to a 70 degree core temp, one might expect a 23 year life before the plastic cracks and loses its integrity.

    I suspect that much more realistic is full load for 8 hours a day (69 hour life) or even operation at at less than 70 degree core temp (most domestic lighting circuits for example a very under-run) and then one has a doubling in life time for every 6 or 7 degrees, mind you for PVC it is all based on extrapolation from a test 5000 hour life at 101 degrees, and 20000 hour life at 89 degrees. I suspect that local instalation details (like 'exposed to sunshine', or as norman has pointed out, 'touching heating pipes' will be dominant in many parts of a real installation.)

    I expect many well done installtions to outlast the building on that basis.. (average building life in the UK is a few hundred years at present, but that number is not real, and is is only becasuse we are currently building faster than we are demolishing..)"


    regards Mike


    One cable maker's view...

    https://www.whyprysmian.co.uk/cable-design.html


    Z.
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  • 0
    This sort of consideration Mike?


    "Has some tables that suggest that at full all day loading, to a 70 degree core temp, one might expect a 23 year life before the plastic cracks and loses its integrity.

    I suspect that much more realistic is full load for 8 hours a day (69 hour life) or even operation at at less than 70 degree core temp (most domestic lighting circuits for example a very under-run) and then one has a doubling in life time for every 6 or 7 degrees, mind you for PVC it is all based on extrapolation from a test 5000 hour life at 101 degrees, and 20000 hour life at 89 degrees. I suspect that local instalation details (like 'exposed to sunshine', or as norman has pointed out, 'touching heating pipes' will be dominant in many parts of a real installation.)

    I expect many well done installtions to outlast the building on that basis.. (average building life in the UK is a few hundred years at present, but that number is not real, and is is only becasuse we are currently building faster than we are demolishing..)"


    regards Mike


    One cable maker's view...

    https://www.whyprysmian.co.uk/cable-design.html


    Z.
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