Why are there lots of wires coming out of the old ceiling light?

Question

I am replacing the old strip lighhts in the kitchen. When i removed them, one has the standard three wires coming out of the ceiling, red, black & green/yellow. This seems normal. However, the other one has-three reds all already joined together....three blacks all joined together, two yellow/greens tied together and finally a pair joined ,one red and one black.
All i need is a neutral and a live to connect the new fitting. How do i know which is which? Why is a black already joined to a red? Surely this is a live connected to a neutral????

Answer 1

it could be the work of ceiling cat

http://uk.answers.yahoo.com/question/index;_ylt=AlZ4r7jZwjlRPVybbCc55ysgBgx.;_ylv=3?qid=20071219180040AAe2ZFw

Answer 2

Leave the light on!!! (Don't try and switch it off) One set of red and black wires is the supply. The other set goes to the switch. So, you have to connect the incoming live to the black wire going to the switch, then the red wire coming from the switch goes into the live supply on the light fitting. The other black is the neutral supply for the light fitting. Connecting both reds and both blacks together in the light fitting terminals would mean that, when you switch the lightswitch on, you are shorting it out, causing the light to go off and if your gran's house is very old without the correct fuse/mcb in the fusebox/breaker panel, the fuse could not be blowing, and your wiring will overheat and cause a fire.

Answer 3

Yes, you do only need a live and a neutral and an earth for your new light, but the lights that have been previously installed in your house are just the same, and they find their source from other light fittings.

So what you have is a light that has a live, neutral and an earth, WHICH IS ALSO LOOPED to other light fittings. If these are accidentally disconnected, you will find that other lights in the house will stop working, or, worse, you may accidentally remove an earth feed to a light fitting, which is BAD as this is required under IEE regulations.

The triple sets of red, black and yellow/green are the loops,
and feeds, if you have a meter or test device, you will be able to identify the live and neutral feed from the ongoing loops which will use the same colour wiring.

The red, black pair appear to be a switched feed, that is to say, a live feed going off to a switch, and coming back to operate the light. Both of these will be live, and the reason that both red and black are live is the fact that twin cable has two conductors identified as red and black, so when this type of cable is used to run between the switch and a lamp, both conductors are LIVE when the lamp is switched on.

House wiring does become a bit complicated when many other appliances are looped through from one fitting to another. This is an easier way of running the cables and saves a great deal of cable, as it is not necessary for each device to be routed to the main consumer unit, but a single feed to one device can then be shared (looped) onto to other nearby (and not so near!) fittings in the same area.

A light fitting is usually also the SOURCE of the live feed! In practice, the live, neutral and earth feeds go to the light fitting's terminal block (as a convenient anchor point!), and then the live goes on to the switch, usually as a red cable, and comes back from the switch (often) as a black wire which (as it is only live when the switch is on) goes to the live terminal on the light. The classic ceiling rose, is in fact a multi-terminal junction box!

Answer 4

Alex is correct...
Leave it all as it is, the red and black joined together are the switch and looped switch wires and connect to the live of your new light. The three blacks are incoming and looped neutrals and connect to N on your new light. Ideally you should mark the black which is joined to the red with red tape or sleeving. It is black because twin cable has one red and one black core and the red was used to supply the switch. I am assuming from your description that you have one switch which operates two lights??

Ignore the advice from the US unless you want to get in a real mess!!!

Answer 5

There is nothing wrong with the wiring that you have found.

Please ignore all answers coming from the USA (they use words like "hot" and refer to "white" wires). The USA wiring standards are different from ours and their (well meaning)
advice could kill you.

The rose with the three wires (black/red + earth) may be wired straight to your new light fitting. This one is paralleled off from the other (mulitple wired) rose.

The rose with the multiple wires works as follows:

Three joined Reds = 1 from the previous ceiling rose on the lighting ring circuit; 1 to the next ceiling rose on the lighting ring circuit; 1 to the kitchen light switch.

Three joined blacks = 1 from previous part of ring (as per red); 1 to next part of ring (as per red); 1 to the second kitchen rose.

Red/Black joined = black from the light switch (this becomes live when the switch is operated - it should have a short red sleeve on it); red goes to the second kitchen rose.

You should connect the new fitting to the junction of the Blacks (blue wire) and the Red/Black pair (brown wire). Remember to connect all the earths (green/yellow) properly to your new fitting.
If you've done it properly all will be well.

If you sketch this out you will see clearly how it works.
Note that the lighting ring main circuit only includes one of the ceiling roses in your kitchen so the wires that lead to and from the rest of the ring may be drawn as going "into space" on your sketch.

Answer 6

There is probably nothing wrong with the multiple circuits you have found behind one of your ceiling lights. Black wired to red is fine and is probably a traveler for a three-way switch tied to a power source. Both Black and Red are used as power legs. Generally only whites are neutrals, although in remodels nothing is ALWAYS sacred. If you disconnected a light to install a new light, simply use the same wires as before an you will be fine. If you had no light on the ceiling box, then you should use an electrical tester to ensure you get 110-120 volts for your new light. Generally a black and a white is needed. However you might find your power in the red wire. If you connect to a red, check all the switches in the room and turn them to the opposite position in case there is a three way switch passing power to this box. A three way switch can be identified 2 different ways: 1) It does NOT say on/off on it and 2) it has 3 screw on the side, where you only see 2 on a regular on/off switch. Good Luck. PS This is for wiring in the USA.

Answer 7

As an electrically oriented person I would say that this is the work of a previous DIY'er. In a normal ring you would have three reds connected into a ceiling rose, line in, line out and the third to the switch.
Then a red from the switch to an independent connector in the rose.
A neutral in and a neutral out (black wires).
Earth in and earth out (yellow/green).
It's possible that some of the wires are for another fitting somewhere, best get someone more 'au fait' with house wiring to sort it out for you.
I think the previous answerer may be American because UK wiring doesn't normally have white wires.

Answer 8

Stop, put down your tools and listen, some of the answers come close but not quite good enough. A brief explantion follows;

the three reds that are connected together are the unswitched supply coming into the room and the unswitched supply continuing to another room. The third is the unswitched supply going to the switch.

The three blacks are the neutral coming in, the neutral going out and the neutral going to the second light within the room.

The two yellow and greens are the earths, a little concerning because there should be four!!

The black and red that are joint together are the switched live, the black beind the one returning from the switch and the red going away to the second light in the same room.

Connect the light to the Black/red connector to the live of the new fitting. Connect the neutral of the new fitting to the three blacks. Connect the earth to the two green and yellows.

For your information if you are UK based you will be breaking the law by replacing a light fitting in your kitchen unless you are a registered electrician.

Regarding the two green/yellows look carefully there may be two cables twisted together with a single green and yellow sleeve over it giving the appearance of a single cable.

Answer 9

Only a circuit tester can tell you with certainty, but my guess is: take one lead from the three reds, and one lead from the three blacks. The yellow/greens are likely grounds and the black and red cojoined are probably hot, but I can't be sure on this.
Be careful and handle electricity with the breakers off. Good luck!

Answer 10

It sounds like somebody wired some lights together in series. Remove the lights, separate the wires, and test them with a meter or circuit tester to find your hot and ground wires.