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Thermal imaging of cables

Hi all,

So it's a little sunny out, and I have a phone-mounted IR camera, so I thought I'd leave some offcuts of larger cable out to cook in the garden and sense-check my derating assumptions for cables in direct sunlight.


However, I've only really used the IR camera for differential inspections (i.e. that phase is running hotter than the other two) and not worried terribly much about the absolute values, which do change significantly depending on the material emissivity setting.


Can anyone recommend a source for aluminium and copper conductors and black PVC and MDPE / HDPE sheaths after exposure to normal installation treatment? (I.e. sheath roughened a little from pulling in, metal dulled from oxidiation, but neither burnt nor mirror-polished)


The difference between the sunny and shaded side of a 45mm OD single core is quite telling; might try a bundle in trefoil tomorrow!


Jam
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  • Former Community Member
    0 Former Community Member
    PVC would be about 0.85 to 0.95


    MDPE wouldn't be be too dissimilar


    Metals are much more problematic depending on surface finishes - there could easily be two orders of magnitude or more between polished and anodized aluminium - oxidized aluminium is around 0.2 to 0.3


    Similar numbers for copper but if it's had heating, could easily be double or more.


    As you've found out, absolute values are a nightmare - normally if you are looking at say a DB, then anything hotter than say 60C is a trigger value for investigation


    Regards


    OMS


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  • Former Community Member
    0 Former Community Member
    PVC would be about 0.85 to 0.95


    MDPE wouldn't be be too dissimilar


    Metals are much more problematic depending on surface finishes - there could easily be two orders of magnitude or more between polished and anodized aluminium - oxidized aluminium is around 0.2 to 0.3


    Similar numbers for copper but if it's had heating, could easily be double or more.


    As you've found out, absolute values are a nightmare - normally if you are looking at say a DB, then anything hotter than say 60C is a trigger value for investigation


    Regards


    OMS


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