The Use Of 1.0mm T + E In Domestic Lighting Circuits and 5 amp SO's

Discussion in 'Electricians' Talk' started by JP., Jan 24, 2018.

  1. Bazza-spark

    Bazza-spark Screwfix Select

    Hi Joe

    Because it is a factory it is high bay lighting in rows with quite long runs. The current requiremments and length of runs require 2.5mm to satisfy voltage drop etc.

    Kind regards
    Joe95 likes this.
  2. Bazza-spark

    Bazza-spark Screwfix Select

    Snap! lol
  3. Timthetap

    Timthetap New Member

    Can anyone help?
    I have 10 120w highbay lights to fit in a warehouse and I've Been given conflicting advice on what gauge cable to use.
    Do I use 1.5mm
    Or go the hog and use 2.5 to be sure?
    I'm not sure how to work out the correct gauge of wire I don't know the rule of thumb -- how do I calculate it
  4. stateit

    stateit Screwfix Select

    How have you got your job then? Have you bluffed your way in? This is basic stuff.
    Ask your supervisor if you are stumped.
    leesparkykent likes this.
  5. leesparkykent

    leesparkykent Well-Known Member

    mV/A/m, use Ze + tabulated (R1+R2) to calculate Zs.
  6. JP.

    JP. Screwfix Select

    Guys many thanks for all your inputs, for me they are gold dust. I now have full confidence in using 1.0mm and note RS's and Dobbs technique with respect to doubling over. Good stuff lads and thanks once again.
    Last edited: Jan 25, 2018
    WillyEckerslike and KIAB like this.
  7. Joe95

    Joe95 Screwfix Select

    Unphased and Bazza-spark, thanks for that. I hadn't considered the load side of things, I had only assumed it was down to voltage drop.
  8. Timthetap

    Timthetap New Member

    If you didn't get it by the name I'm a plumber, I was asked as to do this as a favour,bird was told it would be a few lights in a garage. But its not.
  9. Timthetap

    Timthetap New Member

    If you didn't get it by the name I'm a plumber, I was asked as to do this as a favour,bird was told it would be a few lights in a garage. But its not.
  10. WillyEckerslike

    WillyEckerslike Screwfix Select

    Hi Tim. I can see you're new here. You have metaphorically just put your head in the lion's mouth whilst a queue of sparkies line up to take it in turns to kick it in the ******. Brace yourself.....!
  11. retiredsparks

    retiredsparks Super Member

    Willy , would the alleged lion be more inclined to open his mouth (and eyes) if it suffered sudden blunt force trauma to the area of the reproductive organs ?
  12. sparky Si-Fi

    sparky Si-Fi Screwfix Select

    Domestic installs its 1mm all the way for me, ever tried wrestling 1.5mm in a pendant?

    As stated a few times, with LEDS conquering the world with its (ahem) high life expectancy and long life it's the only way forward and 1mm will sit there all day in a domestic install on a 6A RCBO with a Heathrow airport runway on every ceiling in the house

    1.5mm il leave that to Switched /non switched fused spur loads
  13. WillyEckerslike

    WillyEckerslike Screwfix Select

    I don't know. Let me know when you've found out....
  14. retiredsparks

    retiredsparks Super Member

  15. Never had to wrestle with 1.5 in a pendant,dress it properly and it is easy.
    1.0 mm t&e is just too flimsy to be faffing about with.
    KIAB, retiredsparks and Dr Bodgit like this.
  16. Pollowick

    Pollowick Screwfix Select

    When will lower trip MCBs become more widely available? Most places only stock down to 6A whereas 3A are manufactured but never available or are expensive.

    Looking at a couple of brands of LED fittings they have interlink connectors and cables so it is only necessary to wire to the first and then use pre-made links direct from fitting to fitting. However the link cables are possibly only 0.5mm and as the MCB should protect the wiring a 3A would be more appropriate.
  17. Coloumb

    Coloumb Screwfix Select

    .5mm is good for about 10 amps
  18. Pollowick

    Pollowick Screwfix Select

    Are you sure?

    Ordinary 1mm T&E in conduit/insulation is only rated for 11.5A

    Table 4F3A which is applicable for 2192Y spec flex is rated at 10A for 1mm, 6A for 0.75mm and 3A for 0.5mm
  19. Coloumb

    Coloumb Screwfix Select

    Yea but what method? For lights on .5mm the bigger problem is fault current vs overload anyway.
  20. Pollowick

    Pollowick Screwfix Select

    Does not specify a method on that table ...

    However, it is way lower than than 10A.

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