Advice Please - 3 Core and earth exterior PIR light

Discussion in 'Electricians' Talk' started by Mattprior, Jan 22, 2021.

  1. Mattprior

    Mattprior New Member

    Hi,

    Wondering whether I could get some advice please.

    I have been having some work done to my porch, my electrician removed the old PIR light and made some changes in order to fit my new PIR light. The old PIR light could also be controlled via a switch indoors.

    Unfortunately he has fallen ill and will not be working for quite a while and cannot ask for guidance. I am rather reluctant to get another sparky around to just fit the light seeing as the bulk of the work is done.

    Using the added picture would someone mind helping guide my on how to wire to the new light. Was unsure as I was expecting a twin and earth.

    I can see a sheethed black cable, brown, grey and earth.

    thanks in advance!
     

    Attached Files:

  2. terrymac

    terrymac Screwfix Select

    You need to test the conductors to establish which of the 3 are
    the neutral ,permanent live ,and switched live.
     
  3. Bazza

    Bazza Screwfix Select

    If the sleeve on the black wire is brown, then probably it is

    brown - permanent live
    Grey - neutral
    Black with brown sleeve - switched live

    what connections do you have on the PIR light?
     
    Philip Hyde likes this.
  4. Mattprior

    Mattprior New Member

    Thanks guys, the new PIR light has twin and earth connections. I have added a photo.

    thanks again
     

    Attached Files:

  5. Bazza

    Bazza Screwfix Select

    Yes, as I thought, you won’t be able to control the light quite like the old one as there is no switched live output from the new PIR/light. So you won’t be able to set it as always on unless it has a pulse over-ride feature.

    To wire the new light up
    Black with brown sleeve to the L terminal
    Grey to N terminal
    Earth to earth

    you’ll need to terminate the brown wire in a separate bit of insulated terminal block.
     
  6. Mattprior

    Mattprior New Member

    Thanks Bazza!
     
  7. Philip Hyde

    Philip Hyde Screwfix Select

    If it has a pulse output (Switch off and on in 2 seconds for permanently on) Use the Black with brown sleeve.
    If not Use the Brown (Permanent live) otherwise if someone turns the switch off by mistake the light wont work.
     
  8. Smokey

    Smokey Active Member

    and you'll need to cover the bare copper strand with some suitable earth sleeving incidentally:rolleyes:
     

    Attached Files:

  9. Alan sherriff

    Alan sherriff Active Member

    First of all the grey cable may well be the overide switch wire, but 99% of Pir,s are pre wired so if you had a separate overide switch it can not be used for that use , if you have purchased a new Pir with a 3 core flex on then my advise would be to firstly get an electrician in , or if strapped for cash obtain a plastic adaptable box and feed your cables in either from the rear or side or bottom to avoid water ingress and then feed yor pir wires in for connecting up , is you have a box with grommets just small hole a push cables through if not cable glands and silicon any suspect water ingress. Then as not test kit bare earth sleeve and the looks like blue and brown conect to your brown and blue and earth green and yellow to bare earth covered at least green yellow tape the grey will be live from overide switch inside so park up in a connector or isolate at the indoor switch, your choice you will have isolated firstly at the consumer unit but do not take for granted it is dead with no idea of what Pir you have and no test kit , this is I the best I can help you with
     
  10. Philip Hyde

    Philip Hyde Screwfix Select

    Can I ask why you think the Grey might be override when there is a Brown and a Black with Brown Sleeve??
    I would imagine a waterproof box is a bit over the top for a light in a porch unless the roof leaks!!!
     
    Bazza likes this.
  11. Alan sherriff

    Alan sherriff Active Member

    I mused to fit seperate overrides untill the pits became 99%% pre wired and used the grey in the 3 core for the switched live if in this case as there is a 3 core cable and the switch inside to avoid switch off switch on to activate for the time set , I assumed the fitting was outside so if internal a j/b or similar would suffice need to know entry in to light either way he will struggle trying to get in to so if not pre wired , just a flex to a connection box would look neat
     
  12. Philip Hyde

    Philip Hyde Screwfix Select

    So It's recommend to use Black as Switch Live not Grey. Op mentioned it's in a Porch So won't need any Jb as cable comes out of roof.
     
  13. Bazza

    Bazza Screwfix Select

    The guidance is not to use black as neutral. IET suggested this many years ago when the so-called harmonised colours were introduced.

    If you ever work on 3 phase you’ll know the old sequence was Red Yellow Blue in that order. The new colour sequence is brown black grey in that order. So blue = grey = neutral is logical.

    Given the brown marker is on the black it’s a reasonable assumption that the electrician as actually paid attention to the old/new colours guidance and followed it.

    OP really should confirm this is how his wiring has been done. A photo of the wiring at the switch will confirm.
     
    Philip Hyde likes this.
  14. spinlondon

    spinlondon Screwfix Select

    It was the NICEIC, not so much a suggestion.
    They want to de-neutralise the black.
     
    Philip Hyde likes this.
  15. Bazza

    Bazza Screwfix Select

    Yes NICEIC suggestion but adopted by IET as the colour equivalent diagrams were included in the OSG for several years after.

    I still remember how the aide memoir for the new colours
    Cow
    Cat
    Ash

    don’t remember much else though!
     

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