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What is the best way to wire ceiling lights?

Arran Cameron
The ceiling rose junction box with its loop-in wiring is now really showing its age and is no longer a practical (or even safe) installation for most residents who wish to install fancy light fittings. It is still, however, the most common arrangement for new build houses and rewires, probably as the result of the electrician's training and how they consider it to be the norm or they cannot think of (potentially better) alternatives.


So, what is the best way to wire ceiling lights? Should neutral wires be taken to the switches or not?
  • Former Community Member
    0 Former Community Member

    Denis McMahon:

    Will this thread run for ever?


    A scan of recent posts suggests two points of concern - junction boxes and accessibility.

    Junction boxes


    I would describe these as non-preferred; they provide extra terminal junctions in places that have no actual function. I am sure I could wire a house from scratch using no  junction boxes. I am sure most diligent electricians would prefer to do the same.

    Nonsense - My previous house was wired from 4No JB locations - these were flush 35mm deep dual socket boxes with blank plates over containing connector blocks and strategically (and discreetly) positioned for ease of access.


    All the ceiling lighting positions contained 1 cable only

    Accessibility


    Many years ago, when accessibility was less-well defined in the Regulations, I had an argument with an electrician who wanted to install a junction box where it would be plastered over. His point was that he and I knew where it was and it would be possible to cut a hole in the plaster to access it.  I would define accessibility as follows.



    • Accessible to touch: Positioned where anyone can touch in  normal living circumstances. Clearly not a place for live terminals.

    • Accessible for inspection: Positioned where they can be touched only after removing some type of cover.  This could include junction boxes in loft areas.

    • Inaccessible: Can be reached only by causing damage to the fabric of the building.

    I would argue that it's inaccessible if it requires damage to the structure of the building - removing panels or opening up a partition isn't preferable - but easily achievable. But see my point above

     

     




     

    Regards


    OMS
  • 0
    4 Dual Boxes? Hmm one side lighting and one side power perhaps  with a metalic seperator in between, comming earths via box adds resiliance?

    Good idea.
  • 0
    "Accessible with the use of a tool" means different things to different folks.

    I  am reminded of the pictures in  this previous thread.  Not sure how easy that sort of thing is to fault find in a hurry, but it is quite typical.
  • 0
    If you ever end up working in flats built in the 60’s and 70’s, particularly social housing flats, you will often find that the lighting circuits are installed in the floor screed of the flat above in what is basically a plastic hose pipe  consisting of three tubes, connect conduit boxes sunk into the ceiling formed by the soffit of the concrete floor beams at the lighting points and KO boxes at the switch points with single core single insulated conductors between them.


    No one even considered that someone would want to access a cable mid run, why would they, everything was installed from the switch and lighting points with the cables being fed through the conduits.


    Andy Betteridge
  • 0

    Denis McMahon:

    Will this thread run for ever?



    Yes, by the looks of it.

    Junction boxes


    I would describe these as non-preferred; they provide extra terminal junctions in places that have no actual function. I am sure I could wire a house from scratch using no  junction boxes. I am sure most diligent electricians would prefer to do the same.

    Yes, I'll go along with non-preferred, but only in a new build. That said, I have used them with the express agreement of the householders. Their position is well-documented and they do realise that any future access will be through the ceilings below.

    In an ideal world one would wire a house with foresight of everyone's requirements for at least the next 50 years. We do not of course live in such an ideal world.

    Well, this particular couple have tried to think of everything. For example, on the first and second floors, there are gaps in the underfloor heating where a lift could be installed. There will be a blank in the CU for the circuit.

    Accessibility


    Many years ago, when accessibility was less-well defined in the Regulations, I had an argument with an electrician who wanted to install a junction box where it would be plastered over. His point was that he and I knew where it was and it would be possible to cut a hole in the plaster to access it.  I would define accessibility as follows.

     



    • Accessible to touch: Positioned where anyone can touch in  normal living circumstances. Clearly not a place for live terminals.

    • Accessible for inspection: Positioned where they can be touched only after removing some type of cover.  This could include junction boxes in loft areas.

    • Inaccessible: Can be reached only by causing damage to the fabric of the building.


    That's a very helpful analysis.


    You can argue this however you will, but lifting carpets, IMHO, is not causing damage to the fabric of the building. Lifting boards is more troublesome, but provided that it is done carefully, is at most, repairable damage.


    This is one reason why I do not share Mrs P's aspiration to have floor tiles in (upstairs) bathrooms. I might add that when I restored my breakfast room, I had to replace about 30% of the boards, largely due to plumbers' (heating engineers'?) hamfistedness.


    May be I am too used to older buildings. I would certainly agree that sheets of composite board, underfloor heating, and tiles, make whatever is below inaccessible; so is anything in walls under plaster, tiles, or wainscoting; but for me, floorboards are there to be taken up! ?


    Rewiring is a different matter. Would you re-open (or enlarge) an existing chase in order to avoid a JB?
  • 0

    Denis McMahon:

    Will this thread run for ever?




    The beauty of traditional discussion forums is that threads can run for weeks, or even months, and retain their vigour whereas on Facebook discussions go stale frighteningly fast, sometimes in just a matter of a few hours, and often die completely when the next topic is posted.


    I find it sad that society is turning its back on traditional discussion forums and the younger generation sees them as old school or only inhabited by social misfits past the age of 40, and instead prefers to use that ginormous spy machine called Facebook.   


  • 0

    Dbat:



    Maybe they don't make one as the ceiling rose or loop at the switch works perfectly well, and also doesn't leave random blank-plated double sock boxes dotted around the house?




    OMS:


    I often used a double socket box strategically positioned as a joint box for a group of luminaires and switches (what was often known as RB4 method after the catalogue number of the JB)

    Contradictory viewpoints.
  • 0

    OMS:


    In my opinion yes (but that very much depends on the luminaire that's being installed) - a ceiling rose with loop in is pretty bomb proof - cramming all the connections into an IKEA chandelier less so)

    In an installation where just one cable emerges from the ceiling for each ceiling rose or light fitting, there are only 3 possible faults at the light fitting end:


    1. Open circuit - the light doesn't work when it is switched on.


    2. Short circuit - the breaker trips when the light is switched on.


    3. Loose connection - the light flickers and the terminals get hot.


    In a loop-in installation where 3 cables emerge from a hole in the ceiling for each ceiling rose or light fitting, there are additional faults including:


    1. The light in the room works when it is switched on but downstream lights don't work when they are switched on.


    2. Downstream lights only work when the light in the room is switched on.


    3. Downstream lights flicker.


    4. A permanent short circuit - the breaker trips when no lights are switched on.


    Fault 2 is generally caused by incorrect wiring of a light fitting rather than deterioration of the installation.
  • 0
    For the loop-in installation you missed out

    5. Permanently on - the light has been connected to the loop live connection instead of the switched live......again caused by incorrect wiring, but a lot easier to spot than 2.

    Alasdair
  • 0

    Alasdair Anderson:

    For the loop-in installation you missed out

    5. Permanently on - the light has been connected to the loop live connection instead of the switched live......again caused by incorrect wiring, but a lot easier to spot than 2.




    I had already thought of this. It's something I could write volumes about as the epitome of a botched DIY installation.


    A few other faults as a result of incorrect wiring:


    6. The light is permanently on and when the switch is closed it short circuits the live and neutral, tripping the breaker.


    7. The bulb is wired in series with the downstream lights and only comes on (at half brightness) when a downstream light is also switched on.


    8. The bulb is wired in series with the downstream lights and only comes on (at half brightness) when a downstream light is switched on. When the switch (for the light in the room) is closed it short circuits the live and neutral, tripping the breaker.



     

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