- Reaction score
- 186
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?
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?