...I have two ceiling mounted lights in my flat (same room off a plate with two separate switches), which I want to change for simple ceiling roses with light bulbs and shades. I was hoping if I looked at the current wiring I would be able to figure out a simple solution referring to the ceilng rose instructions, but what I was faced with threw me!
There are four thick grey cables from the ceiling, all with a black and red wire, and one thick green earth (I presume) which splits into each cable. My ceilling rose only has room for three cables.
All the reds were forced into one separated small white connector. Then, in the white plastic connector with three adjoining sections which was connected to the light, The earth went into the centre, three blacks went into one side and one went into the other.
I tried to work out how to wire the ceiling rose, but I couldn't get it all to work properly. It's connected to the other light in the same room, and must be connected to the light in my bathroom (which also has an extractor fan) as the reaction of these lights varied with each different wiring attempt.
I would love to learn how to do it myself, but fear that it is just too difficult.
OK, the four lives that are separate can be left as is. This is the live loop, a live to the other light and the live feed down to the switch.
The single black wire should have a bit red tape or sleeving on it. This is the live return from the switch. ie this wire goes live when the switch is in the on position.
In your new ceiling rose this will connect to the terminal that feeds the brown wire of the light fitting.
The three blacks are the neutral loop and the neutral to the other light. In your ceiling rose you will connect this to the terminal that has the blue wire of the light fitting.
Your earths sound like they have put all 4 wires within the 1 sleeve which is fine. You need this to be connected to the earth block in the ceiling rose which may or may not have an earth wire for the light fitting.
Thanks for the comments. I'm not actually a sparky to trade, but I have been doing my own electrical work for years after doing lots of reading etc. Touching wood, I've managed not to fry myself or set fire to anything so far.
On to your question.
If its already on its own and everything is working it will be the right one. Its quite common to find them unmarked.
To make sure, I would firstly kill the power, then find the red that is part of the same cable as the single black and temporarily disconnect it from the others. You then need a buzz tester which you place over the single black and the now single red. With the light switch off, no buzz. Turn switch on it should buzz as you have made a complete circuit.
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