Lighting wiring help needed please

[robpal]

Hi all i need help after removing an old floodlight which had rusted and siezed i am left with 2 sets of wires each with a black, red and earth (stripped wires twisted together)

I tried to connect them to a standard PIR floodlight and the fusebox has tripped
Now i cant get the downstairs light circuit working again the floodlight is wired to the lighting circuit and has its own switch within the kitchen light switch (double)

I cant even work out how to connect the circuit back up without the light for now.

Please help

 

[riveralt]

I take it you didn't record the L/N/E positions of the cables from the previous 'rusted' lamp.

You also don't say what terminals the new lamp has - I will assume L/N/E/ and how you have wired it.

It is possible that the old lamp formed part of the lighting circuit loop and this is why you have lost power - though if this is the case and the old lamp wasn't the first on the loop some of the lights should be working.
It is also possible that the switch is acting as the loop.

What is the wiring position behind the switch - photograph of the rear with the cables in situ would be helpful pointing out which of the two gang switch cables are for the outside light.

 

[robpal]

unfortunately i had to break apart the old lamp as the screws etc had rusted to dust and ended up cutting wiring out so couldn't note old setup (clumsy i know)

the new PIR floodlight is a std argos job and has a 4 teminal blocks inside with the lamp/pir wired on the left of the block and free terminal on the right of all but the bottom connecter:-

Left - Right
Earth - free
white (to one side of lamp elemnet)/blue - free
brown - free
white (to one side of lamp element) - red (to lamp)

so there remains an earth, neutral and live free as denoted above

i dont know exactly how the 2 main wires from roof/celing are connected behind the scenes but they look identical (grey twin and earth) both have a black, red and have the bare earth twisted together

the old lamp was turned on and off by the indoor light switch -
left switch - outside light
right switch - kitched light

the indoor light switch consists of 3 terminals at the top and 3 at the bottom and is wired like this looking from the back

top left - black with brown sleeve (same core as middle bottom)
top middle - empty
top right - black with brown sleeve (same core as bottom right)
bottom left - empty
bottom middle - red
bottom right - red
and there is an earth wire on back plate

i hope you can determine what is what from the above info i'll post some pics 2morrow if you like (no main lights working downstairs)

the internal wiring is/should be all up to date as we had a new panel and wiring sorted out and certified - this outdoor lamp is wired above the kitchen celing in roof space so has old wiring from the switch on??)

Thanks for your help really appreciate it

 

[riveralt]

the indoor light switch consists of 3 terminals at the top and 3 at the bottom and is wired like this looking from the back

top left - black with brown sleeve (same core as middle bottom)
top middle - empty
top right - black with brown sleeve (same core as bottom right)
bottom left - empty
bottom middle - red
bottom right - red
and there is an earth wire on back plate

Obviously a picture will give me a better idea how the switch is wired.
But some two gangs are divided by a line down the backplate that divides the two gangs into pymriads usually with C at the top and L1 and L2 at the bottom. The next pymriad may be upside down so L1 and L2 at the top and C at the bottom. It sounds from your description that you have this arrangement.

I take it there is no little link cable between any of the terminals.

Can you put the cable colours in the right terminal markings so what is the
C L1 L2 for the outside light?
And the same for the inside light switch.
It does sound as if you have a live and switch live and earth at the switch but live/neutral and earth at the new lamp position.

It is possible that the reds at the old/new lamp position are the loop and should go in their own terminal block - on the lamp - one of the black(brown sleeve) is the switch live and should go in the L teminal at the new lamp and the other black is the netural - which goes in the N terminal - also put the earths in the earth terminal.

You might need a multi-meter to test to see which black cable is acting as the switch live.
You don't say what type of fusebox you have but if it is a semi rewireable you may have blown the fuse wire hence no power to the lights - I take it you have changed the fuse or reset the MCB if you have one of them.

 

[robpal]

I Have included accurate images of the switch, light and outdoor wires

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• robpal
• 25 Mar 2012
• 1

Untitled

• robpal
• 25 Mar 2012
• 1

Untitled

• robpal
• 25 Mar 2012
• 1

There appear to be no link cables between terminals in the light
I have a multimeter what is the best thing for me to do ?

thanks

 

[riveralt]

Okay you need to concentrate only on the part of the switch that controls the outside light.
With the power off.
At the switch connect together in a terminal strip the red and the black/sleeved conductors.
Turn you multi-meter on and set it to continuity or low ohms.
Then at the lamp test between the reds and the blacks until you find which pair give you a low ohm reading - this will now contain the switch live black - mark it in someway (red tape) so you remember which one it is.
At the switch reconnect the red and black back in the terminals they came from.
At the lamp ----- Again you don't say on the drawings what each terminal strip represents - it will be in the instructions - but from your drawing it looks like you have earth, neutral and switch live.
I am not sure sure what the white wire represents but I would guess this is a link to a second light.
So at the lamp you will need to put both reds in its own separate terminal block and tape it up.
Put the black you identified and marked with (red tape) into the switch live (opposite the brown) - put the second black into the neutral (opposite the blue) and the earth to the earth.
Re-set the fuse/MCB.
Remember this light has a PIR so you will need to follow the lamp instructions on how to set it up to work.

 

[robpal]

Thanks for keeping up with me here -

ok so i was testing as i got this mes and i tested for continuity on the light switch and when i switched it the circuit opened and the meter fluctuated (as oppose to 1)

So i guess this is the same as connecting them both together as you have suggested

i then at the floodlight end tested the bare wires and found the black which resulted in the meter fluctuating again

i have now put this black to the floodlight brown (this is the switched live)?
the other black to the blue
earth to earth
and both reds are together in a terminal block of their own

The issue i have now is that i have reset the MCB but can't get anything out of any of the downstairs lights ??

sorry to be a pain really appreciate your help!

 

[robpal]

Just to give you as much in fo as possible

the floodlight wiring info just says

connect brown to live
connect blue to neutral
connect earth to earth

as per diagram these represent the right h/s of the 3 blocks that are free the rest is the lighting internal wiring and is all preset

my consumer unit is a CPN (63a)
and the light circuit mcb is CPN MC106b b6

 

[riveralt]

You do need to test as I have stated to properly identify the black switch live at the lamp.
If you are sure you have the correct switch live at the lamp and the lamp and the other lights do not work then there are two possibilites -
Either the lamp is broken - you can check this with the multimeter but it does require you to test the circuit live.
Switch you multi meter to volts and test between the live and neutral, switch live and neutral (with switch closed), live/switch live and earth and earth and neutral.
If you have power then you should get 230/240v for each test except the earth and neutral which should give you zero volts.

Or you have a problem elsewhere on the circuit and I cannot help you on that.

If you have tried everything above then get a terminal strip and put the two looped reds in one terminal - one black(red sleeve) switch live in another, the other black in a third and the earths in the fourth and see if that brings back the power to your other lights.

 

[robpal]

hmmm well i've removed the light from the equation and looped the 2 reds and put the black in one empty terminal block and the switched black in another and earth on its own and i'm not getting anything from the downstairs lights circuit

When i removed the old light the mcb switched off (a wire sparked)

Why will none of the lights work on the downstairs circuit what could have happened between the mcb flicking off?

 

[riveralt]

One assumes that you also put the neutral in its own terminal strip as well.

The problem is that we don't know for certain how the original lamp and thus the circuit was wired and whether a neutral or a live has been borrowed from another circuit.
My guess was that the power comes into the outside light from a junction box or ceiling rose (as one red/black - cable 1) giving us the live and neutral at the lamp and cable 2 (red) took the power to the C terminal at the light switch then brough the switch live up (black) to the live terminal at the lamp.
Okay separate out all the cables apart from the earths into separate terminals in a terminal strip.
You will have to work live for this one - MCB on.
Multi-meter to volts and light switch off.
1. Test between the red and the earth = should get 230v if not the power is not getting to the lamp and tthe problem could be elsewhere.

Edit - removed no need to test switch see later.

 

[robpal]

One assumes that you also put the neutral in its own terminal strip as well

by this do you mean the black?

i have 2 reds connected together
1 black
1 black which i tested as switched live?
and the earth

 

[riveralt]

One assumes that you also put the neutral in its own terminal strip as well
by this do you mean the black?
i have 2 reds connected together
1 black
1 black which i tested as switched live?
and the earth

Yes that is correct.
If they are put in their own terminals in a terminal strip - we can identify which cables have power coming into the lamp.
With them all separate - might as well separate the earths as well.
You should have power for only one cable with red (live) black(neutral) and earth L/N and L/E = 230v and E/N =0v.
Separating them out should also remove the possibilty of short circuit which is probably why the MCB tripped.
As I said if we can establish the fact that we have power to the lamp then we can start to track back the circuit.
If there is no power there then you will need to conduct further tests on the circuit at ceiling roses and possibly light switches.
Remember that lighting circuits are radial in design they would normally loop in and out of ceiling roses. If there is a break in the circuit then nothing after the break works - but everything before should.

 

[robpal]

Hi been a busy wknd with kids but I've tested the seperate wires and the switch and not gettin any reading from them (multimeter works fine on other circuit) above the floodlight in roof space is a 3 way junction box which seems to have the same wiring in - that is dead too. All I can tell u is that when I switch the PCB on the utility room bulb flashes on for a second the circuit doesn't trip but no power - obviously all other circuits inc upstairs lighting work fine Think it may be time to call in a pro despite being skint this month (I was fitting new light to up security after bike being stolwn from back garden) Riveralt you have been superb and I thank u for taking the time out to help unless u have anymore suggestions I will try and get a spark to have a look

 

[robpal]

Update got an electrician out that family use - turns out the MCB for the lighting circuit is blown and needs replacing - dam my next steps were to test at the panel end and work back - but tbh im no pro as you can tell and could potentially end up doing more damage you just never know how close or far away you are sometimes and i dont have alot of time on my hands so..

for the call out, diagnosis and to label the correct wiring at the light end
£35

riveralt thanks again for all your help i've certainly learnt from it