Bought a new ceiling light today to replace the crappy standard flex in my study.
Problem is I removed the ceiling rose and all wires connected to it without really looking as to how they were connected....
I thought it would be a straight forward swap but the new unit has a block of 3 junction terminals to wire into.
Now the ceiling has 5 reds, 3 blacks and 3 earths. I struggled to get all these into the new terminal but succeeded in the end (I think).
Problem now is when I put the power back on the new light stays on regardless of the switch position. :confused:
I guess I've dopped a clanger somewhere.
Can anybody advise?

Thanks

Nick

You need to seperate your switched supply (usually a neutral) from rest of loom & just feed that alone into the light with the rest in a seperate connector.

Tell me what cables you actually have and I'll easily be able to tell you where each goes:thumb: .
The grey outer bit denotes the cable, the coloured inner bits are cores.
So for instance, do you have 3 grey cables with a black and red core in each, and 1 grey cable with 2 red cores?

For instance, this is only one cable. But it has 2 cores and an earth.
Hence the name twin and earth:thumb:
http://img.alibaba.com/img/product/photobank/2/ro/2roslahan/offer/1150996544464.jpg

Ignore the earths for now, I suspect you actually have 4 but 2 of them are twisted together. they all go in the same terminal anyway so it's not important.

If it's as above:-
the twin red goes to your switch, so one of the reds in that cable goes with ALL the other reds in the terminal marked 'Loop' (Usually in the centre and has 3 holes)
The other red goes in the terminal marked 'L' or 'Live' (At one end, and usually has 2 holes)
All the blacks go together in the terminal marked 'N' or 'Neutral' (At the opposite end to 'L', and usually has only 2 holes)
And all the earths go in the earth terminal

Repeated post, please ignore or delete:norty:

You need to seperate your switched supply (usually a neutral) from rest of loom & just feed that alone into the light with the rest in a seperate connector.


I don't think so, you don't switch neutrals.

Did you have any joy with the prob Scoobidude?
Oh and agreed, you most deffinately do NOT switch neutrals:D

Oh and agreed, you most deffinately do NOT switch neutrals:D

Hmmm. I remember when I rewired an old place in the mid-80's I used to do it this way. 'cos that was what the destruction manwell said .... All it is is a switch wire and you ensure you mark the switched neutral. If you're playing with the lighting circuit you should have at least an inkling of how it *could* work ....

I assume the electrical regs. have changed? How would you wire a switch in if not with a switched neutral? Assuming a normal 3 core cable?

Dave

Did you have any joy with the prob Scoobidude?
Oh and agreed, you most deffinately do NOT switch neutrals:D

All done. Thanks for your help everyone.
The switch on the wall contained 2 lives. These were from 1 common "sleeve" so I was able to work it out by finding the other end in the ceiling.

Thanks again


Nick

The most common way to wire a lighting circuit is by using something called a 'Three Plate' System.
You basically get a Permanent Feed and Neutral to every light.
The Neutral goes straight into the fitting, and the Feed goes into something called a 'Loop' connector.
You then run a twin+E down to the switch which carries the permanent feed down to the switch, and a switched live back to the light.
The switched live is often black or blue, but should be sleeved the same colour as the live. Or to use it's correct term 'Phase', since both phase and neutral are considered to be 'Live' cables these days.
The fact that one of the blacks/blues is actually a switched phase is what causes all the problems when DIYers swap their own lights. 99% of them put the black/blue switched phase in with all the neutrals. BOOM, 230volts shorted out:eek:

The three plate system ensures that no terminations are unreachable, since they are all at either a light, a switch, or the consumer unit.
This makes for easy fault finding, and reduces the chance of costly repair work.

There is actually a test we have to do that ensures the neutrals aren't switched. You aren't even supposed to take a neutral to the switch if there isn't a proper termination in the switch for it (This does NOT mean a connector block in the back of the switch). The only way to connect a neutral properly at the switch is by using a double pole switch.
It goes without saying that the Circuit Protective Conductor (Also known as earth) needs connecting throughout.
It is known at the CPC as it is intended to protect the ENTIRE circuit, the cable included, so all cables outside of an enclosure MUST contain an earth.
The only time this isn't the case is an the main tails between the Meter and your consumer unit

And there you have it, switching 'The Basics'

To all of you who wanted to know, I hope you found that useful:thumb:
To all of you who didn't, I hope you skipped this post:lol1:

P.S. Don't even consider doing any wiring yourself unless you have the relevant qualifications and experience. You could endanger life, and in a worst case scenario face manslaughter charges:Suspiciou

John, what about this thread

http://bbs.scoobynet.com/diy-39/550731-testing-live-wires-light-extractor-fan-switch.html

Can you help with that?

:thumb: Replied my man.
Have a good read and report back.
I thought you'd got someone in in the end so didn't reply to it earlier.

cheers John, will post back on the other thread. The money wanted by some electricians put me off just to wire up 1 switch!!

:lol1: Yeah. That's where having a sparky mate can come in handy. I suggest you befriend one:lol1:

The fact that one of the blacks/blues is actually a switched phase is what causes all the problems when DIYers swap their own lights. 99% of them put the black/blue switched phase in with all the neutrals. BOOM, 230volts shorted out:eek:

I got called round to a neighbours' for exactly this problem a few weeks ago. Turns out they had got their 15 year old son to change the light in his younger brothers room. When I fixed the wiring it stopped tripping the circuit breaker but the light wouldn't switch off - the original short had fused the switch closed.

It's such a common problem that in 10 years I think I've only ever seen one "My new light trips the breaker" scenario where this wasn't the case.
In that case he'd decided that clamping the red core tight behind the metal mounting bracket of the light was a good idea:cuckoo: