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What is "cable derating"?

Discussion in 'Electrics UK' started by wonderwire, 28 Dec 2016.

  1. ColJack

    ColJack

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    Irrelavent as to what "the norm" is in your opinion.. the OP asked about de-rating, not "rule of thumb" circuit design.
    If you need to use 1.5mm because the calculations say so then you use it..
    I was pulling a rough example out of the air.
    As I'm a commercial / industrial sparky then it's not uncommon to have to use 50m+ for some lighting runs bunched in conduit/trunking etc..
     
  2. JohnW2

    JohnW2

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    Agreed. However, particularly given that this is a DIY forum, I presume winston was trying to say that it would be extremely uncommon for the calculations to indicate the need for 1.5mm² cable in anything approaching a standard domestic installation (in relation to either CCC or VD).
    Fair enough - but, as above, that is a world apart from nearly all DIY.

    Kind Regards, John
     
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  4. EFLImpudence

    EFLImpudence

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    Plus - there are/have been a lot of posters who, for some strange reason, come here and say they will of course use 1.5mm² for the lights as if it has been instilled in them.
     
  5. JohnW2

    JohnW2

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    Indeed. Mind you, as far as I can make out, an appreciable proportion of electricians also do that, so it has presumably been 'instilled' in them as well.

    Kind Regards, John
     
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  7. ban-all-sheds

    ban-all-sheds

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    As I wondered, maybe they just CBA to carry 1mm on the van for the sake of a trivial cost saving.
     
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