garage lights confusing me !??

Discussion in 'Electricians' Talk' started by Mlr68, Nov 2, 2021.

  1. Mlr68

    Mlr68 Member

    hi all.

    had 2 fluorescent lights in my garage ..with 2 switches either end ...which i stopped using and put a new light in using the old wiring for one of the lights...the other light i left connected..just removed the tube

    anyway today i had the bright idea of removing the last light just leaving my my new light to use..but i made the school boy error of not noting how that tube was wired up and just stripped it out .

    now i'm left with 3 cables to connect and ive got myself well confused about how to do it..

    have done a (very!) basic sketch ...all cable is 2 core and earth ...not the usual 3 core and earth you find with 2 way lighting...basically a power cable from the mcb ....a single switch cable...and the cable that goes to the new light

    it was how it was originally wired ..so i was going to connect the cables into a terminal block inside a junction box...i'm assuming the power cable must connect to the switch 1 cable ...and maybe one of the neutrals used as a live ...same as normal 2 way switching..?

    Garage Lights.jpg

    anyway confused how it should be wired using 2 core and earth ...or if i should strip it out and start again?

    any help would be most appreciated

    cheers
     
  2. Bazza

    Bazza Screwfix Select

    Photos please. Drawings are often what someone thinks is there, not necessarily what is there.

    mans, please clarify, is this going to be one light snd one switch, or do you still want two switches?
     
  3. terrymac

    terrymac Screwfix Select

    Do you have any testing equipment to measure voltages ,and more importantly do you have the knowledge to safely use it ?
     
  4. Mlr68

    Mlr68 Member

    Got a basic power or no power tester ..
    Would like to keep the 2 switches operating the one light

    I have done my part one many years ago

    I could take some pics tomorrow in daylight...but don't of that's going to show much other above what I've already outlined..

    ....power comes from the house in to the garage MCB board..one for lights..one for a double socket ...lighting breaker is wired correctly..that 2 core and earth comes out of the MCB box to what was the fluorescent tube ...would have thought it would have gone into SW 1 first ?
    ....SW 1 and 2 are linked together with another 2 core and earth ...so how it was wired for the tube orginally was the switch 1 and the MCB power cable went into the tubes connections ...I do remember that 2 reds were linked with a terminal block ..

    Could just strip it all out ..get some 3 core and earth ..and wire the 2 switches and a single light as theyre normally done ....
    Or leave it and just do away with one switch and rewire it for that .

    Would rather leave the wiring as it is and just figure out how to connect it
     
    Last edited: Nov 2, 2021
  5. terrymac

    terrymac Screwfix Select

    Are the cable lengths surface mounted/ visible in their whole lengths,so you can determine which is the supply from MCB ,which is the switch cable ?
    If so it's fairly straightforward.
     
  6. Mlr68

    Mlr68 Member

    Yep all surfaced laid ..literally as Ive drawn it
     
  7. terrymac

    terrymac Screwfix Select

    Not quite ,your sketch shows 2 cables present at light fitting,but you have a 3rd , going to second light fitting.
     
  8. Mlr68

    Mlr68 Member

    2 cables ..1 from the MCB (power) ..1 cable from Switch 1 .(switch cable )...these terminated at the rectangle squiggle ..which would have been the tube lights terminals ....this terminal will now have to house the cable from the new light ..so it will either have to go correctly into a terminal block here ..where the other 2 cables are ...if that makes sense !?

    You could treat this point as a ceiling rose..if that makes it clearer ...MCB power in ..switch 1 in ....then the new light added


    Assuming the link from switch 1 to switch 2 would work
     
  9. terrymac

    terrymac Screwfix Select

    The cable going to light fitting would have the live connected to the switched live ,and neutral connected to supply cable neutral, earth's connected together from all three cables.
    The supply live connects to the switch cable live ,the return from the switch Is the switched live ,and as stated already, connects to the live of the cable going to the light fitting.
    Assuming the two way switching is intact and originally turned both lights on and off from either switch.
    And the light fitting only has one twin and earth cable cable present ?
     
    Last edited: Nov 2, 2021
    Mlr68 likes this.
  10. Mlr68

    Mlr68 Member

    So the 'MCB' cable would have it's red cable ..joined with a terminal block to the 'SW 1' cable ...the neutrals and earth's from these 2 cables can go into another 2 terminal blocks

    So as there's only these 2 cables at this terminal ..the neutral and earth from the new lights cable going to this terminal can be connected to the MCB and SW 1 cables neutral and earth .....

    So where does the lights cables live get connected ?

    It can't go in to the same terminal as the 2 other lives that are joined ?

    I tried all reds together ..all neutrals and earth's together in a terminal block but it wouldn't work
     
  11. terrymac

    terrymac Screwfix Select

    No ,you don't have it clear at all. The switch cable doesn't have a neutral.
    The only neutrals are in the supply cable and cable going to your light fitting, they would be together in the same terminal.
    I edited my last post ,please re read it ,in case you missed the additions.
    You need 4 seperate terminal blocks.
    3 earth's in 1 terminal
    2 Neutrals in another terminal
    Live feed and switch drop in another.
    Switched live ( from switch) and live feed to light fitting together in a 4th terminal.
     
    Last edited: Nov 2, 2021
  12. terrymac

    terrymac Screwfix Select

    I tried all reds together ..all neutrals and earth's together in a terminal block but it wouldn't work[/QUOTE]

    That surely would have tripped the MCB ??
     
  13. Mlr68

    Mlr68 Member

    Yeah it did ....that's when I realised I got it all wrong

    Been up since work at 2 o'clock this morning so not firing on all cylinders... I'll have another look at it tomorrow
     
    terrymac likes this.
  14. Bazza

    Bazza Screwfix Select

    If you only have 2-core and earth between the switches the circuit would have to be wired like this
    BC33A9BB-FE64-485A-9AC2-B6A7A183E0FF.jpeg
    (ignore the intermediate switch in the middle.)
    Probably you need to rejig your wiring like that.
    What other cables are in the switch boxes?
    Photos not drawings please!
     
  15. Mlr68

    Mlr68 Member

    With fresh eyes I've sorted it this morning

    Turned out switch 1 was faulty as well which didn't help

    Cheers
     
  16. Bazza

    Bazza Screwfix Select

    With respect, the switch probably was just fine until this happened.…
    that tripped the MCB, but not before the short circuit - that you created - had fried the switch contacts!!

    glad it sorted now.
     
    Mlr68 likes this.
  17. Mlr68

    Mlr68 Member

    Thanks ...yeah I originally linked the reds from the power in ..and the switch ...but then accidentally connected the 'live' switch neutral.

    Anyway job done now.

    Thanks again
     
    Last edited: Nov 3, 2021

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