Need help replacing ceiling light

[m1l4n]

Hi,

I just recently bought a house and I am trying to replace the light in the bedroom with a new one but I can't get the switch to work.

I've got 2 black, 2 red (joined together) and an earth wire as in the below image:

View media item 76506
I am tring to connect the below light fitting:

View media item 76507
This is what happens when I connect the wires:

Black#1 & 2 Red --> light is always on (regardless of the switch)
2 Red & Black#1 --> light is always on (regardless of the switch)
Black#2 & 2 Red --> no light
2 Red & Black#2 --> no light
Black#1 & Black#2 --> no light

Black#1 is the one that lights up when I use a tester.

Please help, I have been stuck on this for 3 days now! What do I need to do to get it working?

Thanks in advance.

 

[PrenticeBoyofDerry]

Are you sure that Black 1 is always live and not one of the reds?
Does black 1 come live only when the switch is closed and then dead when open.
As the normal set up would be for one black to be neutral posible black 2 in your case.,
The the second black to be the switch live (should be ID by red tag, but not always done).

One of the reds would be permanently live and the second red would go through to the switch, and return via the switch live.

So you need to ID your perm live and your switch live and neutral.

*In most cases the two reds would be connected together as one would be perm live and the second to the switch.
They are not connected across the light, so you require a separate connector (do not twist together and tape up).
*Then the switch live goes to the Live side of light (could be black 1).
*And the neutral (possibly black 2) to the neutral side.
*all earths to earth terminal, if no earth terminal on fitting, they must be kept terminated together to keep continuity around the circuit, so again a separate connector and all together.

Once you have done this it is advised to check you have kept earth continuity around the circuit and all earths are terminated making good contact.

Please note neon type test screwdrivers are not a good or safe method of testing for live, use a two pole/probe tester.

If you look at the image below and exclude the cable going to the next fitting, this would be similar to what I would expect you to have.

Untitled

• PrenticeBoyofDerry
• 22 May 2013
• 6

 

[m1l4n]

Thanks PrenticeBoyofDerry

The diagram you have is exactly what I thought I should be doing, I joined the 2 reds, and connected the 2 blacks to the light fitting but there is no light. The 2 blacks are identical and I couldn't distinguish visually which one is the switch live. But this didn't work regardless of the switch being on or off. I tried several times and swapped the blacks around but no light whatsoever. I am wondering if some of the cable got damaged while I removed the old light.

I will get a probe and try again, will update tonight.

Thanks

 

[DaftPunk]

Do you have a dimmer switch? As you've connected both reds and both blacks together you've created a perfect short circuit which 1000's of amps will have flowed through destroying any dimmers sand possibly even a normal light switch.

 

[m1l4n]

Yes I do have a dimmer switch

So if I replace the switch it should work?

 

[winston1]

As you've connected both reds and both blacks together you've created a perfect short circuit which 1000's of amps will have flowed through destroying any dimmers sand possibly even a normal light switch.

I've read through this thread thoroughly and nowhere has he/she said that he/she has connected both blacks together.

 

[m1l4n]

Hi winston1,

Although I didn't mention it in the post, I did do that at one point, I connected both blacks to one point on the new light fitting with the 2 reds on the other.

I got so frustrated, I tried every combination possible! I did replace few lights in my previous place but that was a brand new flat which only had a brown and blue wires.

 

[PrenticeBoyofDerry]

Sounds like you have fried the dimmer switch then, a replacement will be needed, just to add in future take a note of existing conductors and the terminal markings, label up the cables as it helps. Also testing is important, so get a two probe tester and do not energise until you have proved it is safe to do so.

 

[Taylortwocities]

Replace the dimmer with a standard light switch while you get the light working.
Once that is OK, go buy a new dimmer.

 

[m1l4n]

Thanks everyone, bought a 50p normal switch and it worked!

 

[PrenticeBoyofDerry]

The magic of 50p accessories