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Discuss Downlights wiring...it's not right (standard but is it wrong? in the Lighting Forum area at ElectriciansForums.net

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While I'm not adverse to playing about with different configurations on how to connect up downlights in a room, subject to access, cable lengths, work/time involved, etc.... it does amaze me sometime when I try to figure out how others have done it.

So was at a friends house the other day and he mentioned he was having an issue with one of his downlights. Basically it had flickered and light had went out - he had assumed LED blub had gone. Replaced with a new LED blub still not working, tried known good LED blub from another downlight and still not working. Could I have a quick look?

Of course this should be easy. (Tools at home, so only access to friends basic screwdrivers and multi-meter you get from a Christmas cracker). So total of 8 downlights, in two rows of four, 3rd light from end of 1st row not working. All others working fines. So thinking loose connection. Popped out the suspect downlight to find, what I had assumed as T&E 'feed in' and 'feed out' to this downlight had come loose. At this point found it strange only this light was not working, so started to question how this was wired up.

Won't normally do this, however it had me puzzled, so with assumed 'feed in' and 'feed out' physically separated, turned power on to find both of these were 'live', reading ~230V. Beginning to doubt this multi-meter, so connected up suspect downlight to 'feed-in' now working fine, all lights on. Disconnected 'feed-in' and connected suspect downlight to just 'feed-out' all lights on.

Dropped all other downlights, every single one had two T&E cables going into expect downlight #1, which was closest to light switch, had three T&E cables. At this point I went home to get my tools.

Cut along story short, SL to downlight #1 (3 cables) was split to feed each row of four, only for end of each row to be connected together i.e. in ring.

I personally was not happy with this and disconnected T&E between downlight #1 and downlight in row next to it. So max number of T&E cables going into each light is now two and we now have an end downlight in this chain - back to traditional daisy chain radial configuration. R1+R2 and Zs readings are fine.

However I now questioning myself, after the event, as why in ring in the first place (I did get an answer to this - share with you later on) and what are the associated risks of doing it this way.

So ignoring the obvious fact we have a radial supplying a ring, the more I think about this, the only downside I see is extra cable involved along with the normal ring fault finding concerns. I don't see there being any increased risk as it related to cabling as protected by 6A MCB, no risk of cable overloading, if anything, underloaded on ring portion. Of course you could have one cable pop and be live in the celling space, and you won't know as all downlights would still function as normal....think I may have answered part of my own question.

Thoughts?
 
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littlespark

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No reason it was done in a ring except the spark told the 1 year apprentice to wire it??

Or it was a kitchen fitter/ DIY Dave
 
Good guess. I'll keep you in suspense for a while longer.....
Originally wanted 2 switches to light up the banks of downlights separately But could find the right light switch and the cable had already been run in so made it a ring that could be split later and then forgot all about it?/
 
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Originally wanted 2 switches to light up the banks of downlights separately But could find the right light switch and the cable had already been run in so made it a ring that could be split later and then forgot all about it?/
That would make perfect sense.....if only it was that clear.
 
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Why it ending up in a 'ring'?

Originally plan was for 8 downlights in a different configuration. Two rows of three on outside and a row of 2 on the inside. Two gang switch, outside row lights controlled by one switch and inside row light control by other switch.

Ouside row #1 #2 #3

Inside row #7 #8

Outside row #4 #5 #6

(Snailspark look good for getting full marks - at this point)

Kitchen fitter/electrician at the time had said that he didn't think he would need the inside row lights, so before installing inside lights, he would install outside row lights first and if friend still wanted inside lights after seeing outside lights then we would install them after. - Makes perfect sense.

Friend agreed inside lights were not needed after seeing outside row lights. Everyone happy....well when I say everyone, his wife was not entirely happy after kitchen had been fully fitted and bills paid, she wanted more light at end of the rows but was okay with not having inside row lights.

A year or so later, friend eventually gave in and attempted to do this himself. (Didn't want to ask for help after all, he had made the executive decision to go with just six downlights. Pride at stake here - this part I've assumed to the case). So he watched YouTube, cut holes for new downlights. Reposition a few of the previously installed downlights, so everything didn't look out of place. - Done a great job BTW.

Outside row #1 #2 #3 #7

Outside row #4 #5 #6 #8

However it transpires (after putting him under the spotlight - and promising never to tell his wife this part) when repositioning originally downlights, he 'may' have cut through T&E cable and took no chances and replaced all cable between downlights. When replacing this and adding in new downlight cabling, he knew they 'all' need to be connected up somehow and hence ended up in a ring - after all rings can carry more power for these extra two downlights ;). (Half points awarded to littlespark)
 
Moral of that story is that a husband should never make executive decisions on issues of interior decor.

If a wife wants 56 downlights, let her have 56 downlights. If she wants green lamps in them, get green lamps :D
 

davesparks

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It is quite common for the uninitiated to refer to any circuit as being a ring, I've often heard diyers referring to the 'lighting ring' when they mean a normal lighting circuit.

Maybe someone took this misunderstanding a step further and wired a ring because they think everything has to be a ring?
 
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