Ceiling rose trouble Ask questions and find answers to many subjects relating to electrics and electrical work

[coopervtr]

I tried to fit a new ceiling light in my living today, but when i connect the light to the wiring from the ceiling the switched live will lose all power when its all copnnected in the box.
Could i have got a wire mixed up along the lines somewhere?
There are 3 neutral all together, 3 reds all together, 2 black together and one black on its own (the one i suspect to be the switched live)
Any help would be greatly appreciated,
Many Thanks

[ericmark]

You may get twin and earth with two reds but not two blacks and normally each cable will have one black and one red so even number of each but you seem to have 3 x red but 6 x black this does not make sense?
I would expect in center 3 x Red (Line) then in 3 way block 2 x Black and Blue to lamp (neutral) and in the two way block one Black with red sleeve and Brown to lamp (Switch). If you mix up the switch wire and neutrals you can get a short circuit which will blow fuse/mcb. Please explain what you have.

[kbrownie]

hi
do you mean 3 earths together not neutrals?
reds are okay together
then the 3 blacks two which are the neutrals and a switch wire. switch wire should have red tag on to identify it! This should be connected to brown(Live) terminal side of lamp on ceiling rose.
The other 2 neutrals are connected to blue side Neutral of lamp.
If no red tag becomes a bit tricky! Really need test meter to identify.
Regards
KB

[coopervtr]

there is 3 earths, 3blacks and 3 reds, i believe i have identified the switch wire using a multimeter but when its all connected up the switch loses power.

[kbrownie]

coopervtr,
Where is the power lost is to the light your switching or to lights in other areas.
The wires should be connected so;
All earths(green/yellow) together in earth terminal.
You then have 3 reds
One is an in-coming from previous light or fuse box
One is out going to next fitting offering it a live
One is a switch wire wired to the switch
All these reds are terminated together in the central connection strip in ceiling rose.
The 3 blacks are also in-coming, out going and switch.
The in-coming and blacks(neutrals) are connected to same side as the blue flex on light fitting, should be a 3 terminal connector
The black switch wire is contected to the brown flex side of light fitting, 2 terminal connector.

To identify your switch wires;
Continuity of the switch wires can be found be closing the switch (in on position)
then testing across one black and one red at ceiling rose until find correct combination . All this must be done with the circuit isolated.
Regards
KB