Outbuilding consumer unit

This "thing" about T&E and sunlight is a red herring too, I have seen cables at least 50 years old in this position with only some minor surface roughness from UV damage. NOT a problem.

T&E can indeed be fine, but also it can degrade quite rapidly in sunlight. It all depends on the exact PVC formulation the manufacturer used at the time. In olden days (when I was young) there was indeed no problem and running T&E outdoors, clipped to walls and hung from catenary wires was perfectly normal - and indeed guidance said so. Then, if the story I've been told has any truth to it, someone noticed that some T&E was degrading quite badly and took it up with the cable manufacturers - who it seemed had changed the formulation - but they refuted the claim, pointing out (entirely accurately) that the BS for T&E cables had no requirement whatsoever for UV resistance. Realizing the implications of the problem IEE then does an about-turn and revises the guidance not to assume that T&E has the necessary UV resistance for use outdoors.


So for new installs we shouldn't use T&E in situations exposed to sunlight unless we can find some manufacturer's data stating it is suitable (which mostly isn't there).


For EICRs it's a case of it might be perfectly OK or it might be awful - with no way of telling other than examining the individual cable for deterioration (which in theory should be happening anyway of course).


   - Andy.

This "thing" about T&E and sunlight is a red herring too, I have seen cables at least 50 years old in this position with only some minor surface roughness from UV damage. NOT a problem.

T&E can indeed be fine, but also it can degrade quite rapidly in sunlight. It all depends on the exact PVC formulation the manufacturer used at the time. In olden days (when I was young) there was indeed no problem and running T&E outdoors, clipped to walls and hung from catenary wires was perfectly normal - and indeed guidance said so. Then, if the story I've been told has any truth to it, someone noticed that some T&E was degrading quite badly and took it up with the cable manufacturers - who it seemed had changed the formulation - but they refuted the claim, pointing out (entirely accurately) that the BS for T&E cables had no requirement whatsoever for UV resistance. Realizing the implications of the problem IEE then does an about-turn and revises the guidance not to assume that T&E has the necessary UV resistance for use outdoors.


So for new installs we shouldn't use T&E in situations exposed to sunlight unless we can find some manufacturer's data stating it is suitable (which mostly isn't there).


For EICRs it's a case of it might be perfectly OK or it might be awful - with no way of telling other than examining the individual cable for deterioration (which in theory should be happening anyway of course).


   - Andy.