New light fitting tripping fuse *help*

[tablechair]

Hi,

First post, apologies for any missing info. I am in a bit of a pickle, having thought replacing 2 ceiling light fittings in the main bedroom on Christmas eve was a good idea, the pregnant girlfriend has run out of patience.

The room contains 2 ceiling lights, the issue appears to be related to the wiring of 1 fitting which contains 3 cables, image named 'not_working' that has been uploaded. I have spoken to an electrician who is unable to come out this week and done some research to ensure wiring is correct.

not_working.jpg: Live wires all connected to 'LOOP'. 2 Neutral wires connected to 'NEUTRAL'. 1 Neutral wire off the switch cable connected to 'LINE'. The 2g light switch has a live wire connected to 'COM' and a neutral wire connected to 'L1'. The upstairs light circuit trips, there is no light bulb in and it doesn't seem to matter if the light switch is on or off.

The other light fitting, image named 'working' was working fine with the new light fitting before I touched the second.

I greatly appreciate any advice.

Many thanks,
Dave

1st = not_working.jpg, 2nd = working.jpg

 

[ban-all-sheds]

The room contains 2 ceiling lights, the issue appears to be related to the wiring of 1 fitting which contains 3 cables, image named 'not_working' that has been uploaded. I have spoken to an electrician who is unable to come out this week and done some research to ensure wiring is correct.

Presumably it was all working fine before you fiddled with it, which meant it must originally have been wired correctly? And when you changed it, you didn't replace the conductors where they had been when it was OK?

Live wires all connected to 'LOOP'.

How do you know that they are all live?

2 Neutral wires connected to 'NEUTRAL'.

How do you know that they are all neutral. With lighting circuits you cannot rely on colours, as not all black wires will be neutral.

For example:

1 Neutral wire off the switch cable connected to 'LINE'.

If it's coming from a switch it will be live, not neutral.

How do you know it is the black from the switch?

The 2g light switch has a live wire connected to 'COM' and a neutral wire connected to 'L1'.

Let's hope it doesn't, or when you close the switch you will be connecting L & N together.

What's connected to the other gang of the switch? Are there any link wires between one gang and the other?

The upstairs light circuit trips, there is no light bulb in and it doesn't seem to matter if the light switch is on or off.

What happens if you disconnect all the wires from the rose?

Do you have a multimeter?




BTW - looks like you've got green goo:

//www.diynot.com/diy/search/9986889/?q="green+goo"&o=relevance&c[node]=8

//www.diynot.com/diy/search/9986891/?q="green+slime"&o=relevance&c[node]=8


1st = not_working.jpg, 2nd = working.jpg
View attachment 111004 View attachment 111005[/QUOTE]

 

[securespark]

Re-check with a multimeter which are the neutrals and which the switched line.

Also, if the light with 1 cable feeding it comes on with the other light, one of those reds should be in the switched line terminal.

The only possible short I can see there (assuming all the conductors are marked correctly) is that the switched line from the switch is connected to a neutral. But then the short would disappear with the switch open (unless the mechanism is welded shut).

It looks like you have "green goo" on your cabling, which should be replaced. You should check other electrical accessories for this substance and consider a rewire if it is widespread.

 

[tablechair]

I believed the single cable light fitting is being fed by the other... I thought this might be the issue.

Edit:
I understand what you mean, I have done this, thank you. Now the fuse is not tripping however the lights remain on, the light switch does nothing.

I have lots of 'green-goo' on all the cables in both light fittings - what does this mean?

Thanks!

 

[tablechair]

@ban-all-sheds.

You are correct, it was working fine and I thought it would be easier to replace the fitting that I had just covered with paint rather than clean it... big mistake. I did not photograph the configuration before replacing.

I was relying on colours ;-( & I do not have a multimeter.

FYI, the current configuration has enabled the lights to work (no tripping) however the lightswitch is not working (cannot turn the lights off).

Thank you for the help!

 

[Taylortwocities]

I believed the single cable light fitting is being fed by the other

Well, that was going to be my question.

I guess that you have two lights in the one room controled by one light switch?

If so, one of the reds in the loop in first photo is in the wrong place and should be in the switched live terminal (marked L) on the left.
That will explain why that light is on all of the time.

You'll need a multimeter to discover what is really happening though.

 

[ban-all-sheds]

I do not have a multimeter.

IF you want to work on your electrics, you need one every bit as much as you need screwdrivers, wire strippers etc...

 

[winston1]

The earth wires should have green/yellow sleeving on them and why are there only two in the first picture?

 

[tablechair]

@Taylortwocities
Yes, 2 lights in same room controlled by a single switch. I must have the wrong cable in. I may also invest in a multimeter, thank you.

@winston1
I pulled the sleeves off because one of the 3 earth cables broke so I wrapped it around the other 2, hence why it looks like only 2 earths. I realise this is not ideal

So frustrating, I have tried many combinations but obviously just guessing without a meter.

 

[Astra99]

Is that 3/.029, or are my eyes deceiving me? If it is, then that installation must date from the 1960s I would have thought.

 

[tablechair]

1956 - year of house build. I imagine this is the same wiring?

(Been here a year)

 

[Astra99]

In the 1950s it was unusual to find CPCs in the lighting circuits (unless there were metal light fittings). IIRC it was not until the 15th edition and the mid-1960s that the requirement to put CPCs (earths) on lighting circuits came in. And it wasn't until even later again that the requirement to sleeve the CPCs at terminations came in! If your cables are the (1950s)originals, then your house probably had metal light fittings in at least some of the rooms.

 

[Taylortwocities]

If the PVC cable is oozing goo then it's 1970ish.

 

[Echo the husky]

I realise this is not ideal

It's entirely unacceptable and needs to be corrected.

It looks like the wiring you have should now operate, though you may have the polarity wrong, this need to be proved with a meter. I expect the switch has been damaged by the incorrect wiring and is now stuck on and will need to be replaced. Wash your hands after handling the wires, the green stuff should not be ingested.

 

[tablechair]

It's entirely unacceptable and needs to be corrected.

It looks like the wiring you have should now operate, though you may have the polarity wrong, this need to be proved with a meter. I expect the switch has been damaged by the incorrect wiring and is now stuck on and will need to be replaced. Wash your hands after handling the wires, the green stuff should not be ingested.

Forgive me. I will try and get an electrician in