New light fitting won't switch off

[mikeyw]

Guys,

Just fitted a 3 halogen bulb row spotlight in a bedroom and when the circuit was put back on the light came straight on - at the wall switch I tried turning it off but the switch did nothing, the light just stayed on.

The single light that was in the room before switched on/off fine.

My worry is the cabling is quite old and i've matched it up as follows (Can you confirm this is fine) :-

2black stands - into neutral 3green/yellow strands - into earth 4red strands - into live.

For a start why on earth are there 4 strands of red !!....anyway i've just about got them all into the plastic connecter block. The Black and greens were a little easier.

Does the switch need changing in anyway ? - i'll need to check but I believe there is a single strand of red cable going into the top (L1) and then another out the bottom (L2)

I've fitted another of these fittings in another part of the house where we have new cabling ie (blue, brown and green/yellow) and it switches on & off fine.

Any ideas on what is causing this and what I need to check ?

TIA, Mike.

[Owain]

Because two reds are the live looping in and out to previous and subsequent fittings, one red is the live down to the switch, and one red is the switched live back to the light.

You need to common three of the reds in a single piece of 'chocolate block' and have the switched live connected to the light.

If you can see which cable is twin-red-and-earth that should be your switch wires, as opposed to red-and-black-and-earth which should be your circuit wires.

Owain

[Alan]

In message , mikeyw wrote

As a guess

correct

correct

incorrect

You have a live supply (red) coming in. You connect this to one side of the switch (red) i.e. only two reds connected together.

You need another connection joining the two remaining reds One red will be the return from the switch - the other will be the live terminal of the lights.

No

That's OK

Check your other light - you may find that there are 4 sets of connections and not three

[Clive Dive]

Classic DIY error

SWITCH OFF AT MAINS

2 blacks to neutral. 3 reds on a separate connector [theses are; live in , live out and live to the wall switch.] remaining red to the L connector on the fitting. At this stage you are now wishing that you had marked the wires ' aren't you? Trial and rror unless you have a tester / meter I'm afraid. And when you have finished check that all the other lights are still working!

[mikeyw]

Thanks Alan that's great - my only question now would be how would identify which red strand goes where as all four are identical, however I do recall that they are separeted into two sleeves ie 2 strands in one sleeve and 2 in the other.

Can you elaborate on what goes where ?

Is it a case of taking one red from each sleeve into the live connector socket and then joining the remaining two together with another connection ?

I'll wait for your answer before trying anything !!

Regards, Mike.

[Jim Gregory]

Wasn't there a connecting diagram or an instruction leaflet? As you said, why 4 reds for 3 lamps? Why are there 3 earths but only 2 neutrals? Intriguing! If you've had difficulty inserting 4 wires into a constricted terminal block, you ought to discard it and use a way of the next insulated gauge up. The ceiling connection you called 'live' is supposed to be the 'switched live' via the wall switch. The routes for your other colours seem fine. But it sounds as if the wall switch is not interrupting as it must. Wow! It should handle two wires using L1 and C, assuming it was not once configured two-way with somewhere else! Hope it's fixed in time for Xmas!

[mikeyw]

The 4,3 & 2 strands are what was coming out of the ceiling - the light fitting is wired fine as you would expect. The problem is trying to match up this 'old' wiring configuration with a modern light fitting.....it looks like Alan may have established what the problem is though.

[Alan]

In message , Clive Dive wrote

That would require 5 lives live in live out live supply to switch live return from switch live to lights

The OP said he only had 4.

As a guess this is a spur connection rather than the lights being on a ring.

The OP is lucky that the wires to the switch were BOTH red!

[Alan]

In message , mikeyw wrote

Other people are reading your original post in a different way to me so it's worth waiting until you get some more answers and/or confirmation.

How many red wires come from your new light fitting? Is there one red or three?

Are you referring to the wiring in a ceiling rose or are you writing about the wiring/connectors inside your new light fitting?

[Jim Gregory]

Without disturbing any of the other essential wires, you should have made a sketch and then just re-used the three conns that the original (working) lamp had been connected to. It was an upgrade swap. The reds are typically: 3 continuous line all junctioned and 1 switched line from wall switch.

[ARWadsworth]

live return from switch and live to lights are the same thing, so 4 red wires would indeed be correct.

Lights are supplied by radial circuits not rings

I would have expected there to be one red/red twin and earth and two red black twin and earth cables. The red/red being the one that goes to the switch.

Adam

[John White]

By the sound of it you have a "loop" in circuit with three cables coming into the fitting. These are two cables with a black core, and a red one with a bare earth wire (covered by the green/yellow sleeving) between them, and one cable with two red cores and a bare earth wire (covered by the green/yellow sleeving) between them.

One of the red/black cables is the supply into the fitting and the other one is going to the next fitting in the chain.

The red/red cable is going to the light switch.

No.

You have joined up the black and green/yellow wires correctly but you need to change the red ones around a bit.

Both red wires from the black/red cables need to be joined in a terminal block along with ONE wire from the red/red cable making a total of three wires in that connector. Insulate that connector with some tape and tuck it well out of the way inside the fitting.

The other wire in the red/red cable needs to be connected to the live terminal on the new light fitting.

Assuming you only have a single light switch on the plate the you can connect the wires from the red/red cable either way round.

Don't forget to turn off the power at the main first!

John

[Dave Plowman (News)]

You're lucky they used special cable with two reds for the switch circuit otherwise your method of all reds and blacks together would have resulted in the MCB tripping when you switched on the light.

I'd suggest a bit of basic learning before fiddling with electricity. Now's a good time to ask for a decent DIY book.

[mikeyw]

Well guys thanks for your help - I understand a lot clearer what is going on now but still am unable to get the switch working.

To summarise here is how the fitting is wired.

On the fitting end there is a plastic connection block with obviously a blue, green/yellow and brown cables connected as neutral, earth & live.

On the ceiling / circuit side I have 3 sleeves of cables - 2 of these contain red, black & earth strands, the 3rd (the switch circuit) has 2 reds and an earth.

On the ceiling side of the connection block i have taken from the non circuit cables - 2 reds into the live, 2 blacks into the neutral and 2 greens into earth. Earth also has the green cable from the switch circuit.

So this just leaves the 2 red cables from switch circuit - I tried Johns suggestion of putting one of these on each live side of the connection block but again no joy.

Can anyone spot where i'm going wrong ? - maybe I need to try changing which side of live the strands from the switch circuit go.

Sorry about this guys but i think we're very close to cracking it !!

Thanks again, Mike.

[Chip]

On 24 Dec 2005 06:05:50 -0800,it is alleged that "mikeyw" spake thusly in uk.d-i-y:

Yep, very close. But not close enough yet

Blacks > both into neutral terminal of the fixture

Green/yellow earths, all 3 into earth terminal of fixture

both reds from the red/black cables and ONE of the 2 reds from the red/red cable into a separate connector (You may need to supply, just to common them up), and the final red from the red/red cable into the live (brown) on the fixture.

Essentially the red/black cables are a feed from the mains and a cable on to the next room, the red/red is the one to the switch, you need to take this to the switch, and then back to the fixture _from_ the switch.

Hope this is clear, just take care with it:-)

[mikeyw]

So chip what you are saying is that only 1 of the red stands goes into the 'live' along with the brown from the fitting on the connection block.

The remaining 3 red strands go into an additional connection block ie separate to the one that came with the fitting ?

Does it matter how the 3 remaining reds go together ? - ie 2 at one end and one at the other or is it just a case of linking all together so effectively they can all go together ?

Am i right in what i'm saying ?

Jeez - I think i'll stick to mending Unix servers...a lot more straightforward !!

[The3rd Earl Of Derby]

mikeyw wrote: [snip]

lol you mess around with logic but you never applied logic before messing with lighting.

-- Sir Benjamin Middlethwaite

[Clive Dive]

NO IT WOULDN'T...READ IT AGAIN. ASSUMING WE ARE TALING ABOUT THE CABLES AT THE CEILING...FORGET THE NEW LIGHT, THAT IS IRRELEVANT. THERE MUST BE 3 TWINS AT THE CEILING...PAIR IN [l&n] , PAIR OUT [l&n] PAIR TO THE SITCH [TWIN RED] THUS 3 PAIRS. COMPRISING 4 REDS AND 2 BLACKS

live in

On a ring? never seen that in 30+years! There again, every day is a school day.

>

[Alan]

In message , mikeyw wrote

Does this help? (scroll down to the first and second diagrams towards the middle of the web page)

[Dave Fawthrop]

| > >>=20 | >=20 | > That would require 5 lives |=20 | NO IT WOULDN'T...READ IT AGAIN. ASSUMING WE ARE TALING ABOUT THE CABLES | AT THE CEILING...FORGET THE NEW LIGHT, THAT IS IRRELEVANT. | THERE MUST BE 3 TWINS AT THE CEILING...PAIR IN [l&n] , PAIR OUT [l&n] | PAIR | TO THE SITCH [TWIN RED] THUS 3 PAIRS. COMPRISING 4 REDS AND 2 BLACKS | >

| live in | > live out | > live supply to switch | > live return from switch | > live to lights | >=20 | > The OP said he only had 4. | >=20 | > As a guess this is a spur connection rather than the lights being on = a=20 | > ring. |=20 | On a ring? never seen that in 30+years! There again, every day is a | school day.

Sh! I have a light, in the loft, run from a fused spur box off the ring main.

--=20 Dave Fawthrop Register your mobile phone=20 IMEI *free* on

Keep the username and password. =20 If it gets stolen report it your provider to get it blocked. To hopefully get it back report on or 08701 123 123.