(another) light not working - help please

[chrisgillett]

Hi all,

I've a very similar problem to Aquarius posting just earlier today but I have added issues so I'll need more help please.

I've been trying to install a new light fitting in my lounge and I made the same newbie error of attaching all the reds, black and earths to each other - cue fuse popped when I turned it all on.

I've since learnt how to re-wire an old block fuse (which needs updating but that is another issue for another day) and I am stuck and none of my other lights in the flat work.

I've looked at the light rose for another in the house that was working before I started messing with it all. The pic is below, annotated for clarity.

Untitled

• chrisgillett
• 15 Nov 2009
• 1

As you can see, I have 3 bunches of red/black/earth but there is no way of identifying the loop from the switch as my red has no black stripe.

I'm fairly certain that this the same arrangement as my lounge before I started. This is what I have in my lounge at the moment:

Untitled

• chrisgillett
• 15 Nov 2009
• 1

I should add that my light switch has just one red, one black and one earth.

I thought I was fairly competent with electrics having rewired plugs etc and quite a lot of my car over the years but I see that houses are more complicated and maybe I know nothing!

I have a multimeter!
Thanks for any help you can offer.
Chris

 

[RF Lighting]

Right first job. Make sure the electricity to this circuit is definatly isolated.

Then, set your multimeter to the continuity setting. The probes should make the meter beep when you touch them together.

Next, turn the light switch to off.

Then touch a probe to one of the red wires, and the other probe to a black wire from the same cable.

Repeat this on all three cables.

You might find the meter beeps, but it might not. Make a note of which do, and which do not.

Then, turn the switch on, and retest all the wires as above. You should now find that one of the pairs of wires will make the meter beep which previously did not.

This is the switch wire. You could confirm this by holding your meter probes onto the wire, and getting someone to switch the switch a couple of times.

You need to mark the black wire to the switch with some red tape or red sleeving.

Let us know when you have done this, and we'll go onto the next stage.

 

[chrisgillett]

I have an analogue multimeter.
I should set it to 250v AC I guess?

 

[disinfo]

I have an analogue multimeter.
I should set it to 250v AC I guess?

No.

As you are hopefully not testing while the circuit is energised, you will need to set it to its lowest ohms scale. Rather than beep the needle will move across towards zero.

 

[chrisgillett]

ok.

I've got:
one that moves the meter all the time
one that only moves with the switch turned on
one that does sweet FA

 

[RF Lighting]

Right, the one that doesn't do anything will be the supply.

The one that moves the meter all the time will be the supply to the next light, and the one that moves when the switch is on will be to the switch.

Assuming your new light has strip connector type terminals, you need to connect it as follows:

You may need to provide an additional piece of strip connector for the loop connection if there is only three terminals on your light.

 

[chrisgillett]

SUCCESS

Thanks so much. If you're ever in Bristol look me up and I'll buy you a beer.

Chris

 

[dizz]

hey - how can posts like this be used for reference - it's very good.

 

[jj4091]

hey - how can posts like this be used for reference - it's very good.

If you look at the shoulder headings there is one called "wikki" - all the info is already available there.