Hi all, apologies for what may seem a simple question, however, I have recently tried to change my kitchen striplight for a 4 halogen spot. I am confused with the wiring out of the ceiling, which seems to comprise of two cables (live and neutral on each) and a separate earth. The light I am fitting two only has a single connector for live, neutral and earth. Am I missing something and what should I do? Thanks.
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It could be the connection to the switch is being taken from right at the light fitting so: live & neutral in to terminals 1 and 2 say, live off to the switch from 1, switched live (on a neutral-coloured line) coming back to terminal 3 and the light fitting connected across terminals 3 (switched live) to the neutral on 2. Earth line connected up as required on terminal 4. It would then look like two power lines coming in to the fitting but it's really the power line and the switch.
Or, if it's an old house, it could be a cable daisy-chained on to another light fitting which might not even be there any more. :roll:
Don't plug your fingers in without pulling the fuse for the circuit.
If you have 2 cable, each one having red, black and a bare earthwire, or brown, blue and a bare earthwire then I suspect this is the last light on the circuit, one wire being the feed in, the other being the cable going down to the switch. You need to safely establish which cable is which with test equipment. Once you've established which one is the feed in then this is your permanent live and your neutral. The other cable goes to the switch.
If you connect the red core in the cable going to the switch(at ceiling position) to the red permanent live(at ceiling position) you then have a permanent live at the switch which goes into the common terminal.
If you then connect the black wire at the switch into the other connection in the switch(L1 or L2) then all the switch does is touch these 2 wires together when the switch is operated so the black wire at the light then becomes a switched live NOT a neutral.
Thats why its important to identify which black is the neutral and which is the switched live so that you can connect the light fitting with the correct polarity!! The switched live at the light fitting should have been marked using red sleeving or red tape and its this wire that you connect to the brown(live) wire in the new light fitting.
The black wire at the light fitting should be connected to the blue(neutral) wire in the new light fitting.
The 2 reds at the ceiling position need to be connected together and insulated but not connected to the light fitting in any way.
And of course if the light fitting requires an earth both the earthwires should be connected to the E or "earth" terminal in the new light fitting.
Sorry its so long winded but its important to be precise. Of course if you have new wiring then in the above description for red substitute brown and for black substitute blue.
I have made some assumptions.
There are other possibilities to your situation so I cant emphasise enough the importance of testing safely to verify before energising.
Hope this helps
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