[kredman]

I've seen a few comments on this topic already, but none reflect my particular situation, so I hope you don't mind if I put forward my case.

I am trying to put a new light fitting up (big heavy brass thing). There are 9 wires hanging out of the ceiling - 3 red, 3 black, 3 green/yellow.

My light fitting has 1 blue, 1 brown, 1 green/yellow.

I tried attaching the blacks to the blue, the reds to the brown and the green/yellows together.

When switching on the lights at the fuse box, they came on despite the light switch being off. One of the bulbs immediately smoked and fused. When I then turned the light switch to 'on', everything fused, and, even with the light fitting removed, I now can't get any of the lights to turn on again.

I hope I haven't done anything fatally wrong...

Please could someone help on 1) whether I've done permanent damage 2) how I should be attaching this light fitting. (note, a 'rose' doesn't fit between the fitting and the ceiling).

Thank you for your help
Kredman

[kredman]

so, after browsing the interwebulator a bit, I discovered that one of the blacks was mascarading as a bad guy. I have separated it, and at least the lights have come back on around the flat. Now I just need to work out how my new selection fits with the light fitting:
3 reds
2 blacks
1 black bad guy
3 green and yellow

Need to fit to
1 brown
1 blue
1 green/yellow.

Any advise greatly received
thanks
Kredman

[canalman]

If this is a relatively new house, then the problem is simple.
The three cables are -
Live and Neutral feed in from the previous light fitting
Live and Neutral feed out to the next light fitting, and
Live and Switched Live to/from your wall switch.
Do this -
1) SWITCH OFF THE POWER to the lighting circuits
2) With a test meter (or the help of a friend with suitable equipment), test between brown and blue of each cable in turn, and in both positions of the wall switch.
You should find that one of the three cables shows continuity in one switch position, and not in the other. This cable is therefore the one that goes to your wall switch. The Switched Live in this cable is usually the blue wire. (Other readers note - in older houses, read Red and Black for Brown and Blue).
Now use one terminal of a small junction box (or a terminal strip, but suitably enclosed) to connect all 3 Brown wires together. Use a second terminal to connect the blue wires of the 'Live feed in' cable and the 'Live feed out' cable together, but DO NOT include the blue of the Switch cable. Use a third terminal to connect all the earths together.
Now connect the blue of the Switch cable to a fourth terminal (at present, this is the only wire in this terminal).
3) Reconnect the Power and check all your lights (except the new one) are working OK.
4) TURN OFF THE POWER on the lighting circuits again.
5) Connect the Blue of your light fitting to the terminal holding two other Blues from the Feed In and the Feed Out cables.
6) Connect the earth wire of your fitting to the terminal holding the other earth wires.
7) Connect the Brown of your light fitting to the Blue (!) wire from the switch.
(This is the return Switched Live, and strictly speaking it should have a red or brown sleeve over the blue to indicate this).
8) Reconnect the power and test your new light. If the wiring is standard, and you have done exactly as detailed, and your light is not faulty, all should now be working.

IF IN ANY DOUBT, DO NOT ATTEMPT THIS - GET AN ELECTRICIAN.
They are cheaper than undertakers - se Hilaire Belloc's poem below -

Lord Finchley by Hilaire Belloc

Lord Finchley tried to mend the Electric Light.
It struck him dead: And serve him right!
It is the business of the wealthy man
To give employment to the artisan.

[canalman]

PS - sorry, I misread part of your post.
You said you have Red and Black cabling (as do the majority of houses).
(The new colurs in cables are brown and blue, like in the flex on the appliances)
In my post above, therefore, for Brown, read Red, and for Blue, read Black.

My bad...

[Russ Svatt]

Kredman - check out the link below, there is a great explanation of how to wire a ceiling rose. the diagrams will show exactly what the 3 wires are for and how to reconnect them: www.ceilingrosewiring.co.uk