Anybody good with electrics? (1 Viewer)

Nick

Administrator
Have a light that broke, so thought I'd try to change it with a new basic one.

Took it off, however now going to put the new one up I realise there are 3 of each cables so I assume it is part of the main circuit into the switch and then the lighting for downstairs.

I have managed to get it so that the other downstairs lights work but for the life of me can't figure out how to get it working.

Is there a way to test which cable is doing what, so which need to go into the light and which need to be connected up?

Will probably just get an electrician out to be sure but it's annoying.
 

Gazolba

Well-Known Member
Just don't mess with any electrical circuit until you have turned the power off to that circuit, otherwise we might need a new Administrator.
Usually wires are colour-coded which tells you which is which.
 

Nick

Administrator
Just don't mess with any electrical circuit until you have turned the power off to that circuit, otherwise we might need a new Administrator.
Usually wires are colour-coded which tells you which is which.

I know that ;) It's just they seem to be in a circuit so I think some need to link together rather than go into the light and then some need to go into the light.

Might just save the hassle and book an electrician, just seems a bit of a small job for one and always get loads of shit with tradesmen.
 

jimmyhillsfanclub

Well-Known Member
Im not an electrician but basically you've got a live and a switched live into to light fitting nick.....you need to isolate that particular lighting circuit on your consumer unit (flip the mcb) then get a meter and do some continuity testing to work out which wire is which......

......Or just phone a spark and he/she will sort it in no time.
 

Nick

Administrator
Im not an electrician but basically you've got a live and a switched live into to light fitting nick.....you need to isolate that particular lighting circuit on your consumer unit (flip the mcb) then get a meter and do some continuity testing to work out which wire is which......

......Or just phone a spark and he/she will sort it in no time.

Yeah have all of the things labelled on the switch panel so turn that off before I do anything, I think it's the figuring out what's what.

Might just phone one up. Just means a day off work for them to come round :(
 

Nick

Administrator
Any numbers or markings on the terminals of the old light fitting?

It went in the bin the other week

giphy.gif


Think I'll just phone about a bit and see if any do weekends or evenings if I hold a torch!
 

Marty

Well-Known Member
It should be fairly straight forward to sort out yourself.

As mentioned, live in, live out and switch live. Identify the switch live with a multi meter and you're sorted. I'm a plumber not a sparks though. :pompus:
 

Nick

Administrator
It should be fairly straight forward to sort out yourself.

As mentioned, live in, live out and switch live. Identify the switch live with a multi meter and you're sorted. I'm a plumber not a sparks though. :pompus:

It isn't just that, it's all the others that go with it.

I have done single ones a piece of piss before but this one is to put it frankly, a bastard.

Will just have to listen to some bloke tell me I need a complete rewire or tell me it's going to be £50 over the phone then randomly demand £300 like last time I called one out.

giphy.gif
 

Marty

Well-Known Member
The others that go with it? So more then one light fitting?
 

Marty

Well-Known Member
Which sounds right, if you have 3 sets, live in, live out, switched live. Should have 9 cables at the rose.
 

Nick

Administrator
Which sounds right, if you have 3 sets, live in, live out, switched live. Should have 9 cables at the rose.

IT's just figuring out which is which. :(

I have let it beat me! It's only the utility room though so don't need a light in there now anyway.
 

Marty

Well-Known Member
Turn off power, go to the switch, take out the wires from the back, twist together, then do a continuity test at the rose. The switched live will give a very low reading, and the rest will show as an open circuit.

Don't remove or test earth, it's unnecessary. Just twist the in and out off the switch
 

stupot07

Well-Known Member
School boy error there nick. Always label when you're changing a light fitting. Assuming its a room with a single light I'm you should have a
- switch live
- 1/2 permanent live
- neutral
And obviously earth

Have you got a multimeter?


Sent from my SM-G930F using Tapatalk
 

Nick

Administrator
Turn off power, go to the switch, take out the wires from the back, twist together, then do a continuity test at the rose. The switched live will give a very low reading, and the rest will show as an open circuit.

Don't remove or test earth, it's unnecessary. Just twist the in and out off the switch

Cheers, that's a bit beyond me though with continuity tests :(
 

Marty

Well-Known Member
It's straight forward, basic stuff. Continuity testing does what it says, you hold one probe on the live. Then with the other probe, you hold it against the other wires in that cable. Everything else should read as an open circuit apart from one. By untwisting the cables or turning the switch off, it'll then read as an open circuit again.
 

Nick

Administrator
It's straight forward, basic stuff. Continuity testing does what it says, you hold one probe on the live. Then with the other probe, you hold it against the other wires in that cable. Everything else should read as an open circuit apart from one. By untwisting the cables or turning the switch off, it'll then read as an open circuit again.
I take it that's with the breaker off? Ha

Might give it a go and get a multi meter from work.
 

Marty

Well-Known Member
No. It's at the ceiling rose. You only need to identify the switch live.
 

Marty

Well-Known Member
The ceiling rose is what the light fitting sits on. The thing that the cables are wired into.
 

Marty

Well-Known Member
Ah, there isn't one. It's just wires hanging out :(

I have them in most other rooms, just not this one.

That's fine, the process still works. Have a quick look on youtube on how to do a continuity test, honestly, it's as simple as it gets and it's a 2 minute job and will save you a fair whack.
 

Martin84

Member
I’ve never heard so many people pretending to know about how to wire a light fitting. Firstly colours don’t mean anything if now wired to industry standards. It sounds like you have 3 x twin and earth cables at the fitting. 2x twin and earths will be permanent LNE from the last fitting then linking at the fitting then off to the next fitting. Next you will have 1x twin and earth which will go off to light switch. One of these cables will connect to the permanent live of the other two cables. The other will loop through the switch and back up to the fitting and connect to the live of the light fitting. See below for a link. FYI most houses are installed with prv cables. There is no reason if installed correctly they should need a hours require. You would expect the cables to last at least 70 years

Home Wiring Guide - Single Way lighting circuit
 

Astute

Well-Known Member
20170919_091239.jpg Does this look anything like what you have Nick? It is one I did recently in a kitchen in a house I am presently doing up
 

Astute

Well-Known Member
This is what it looked like when tidied up a bit. Th red clip around the white sheath is the new wires for the light. If it is similar I will take a finished pic for you later. All simple.

Before

20170919_090901.jpg


After

20170919_092801.jpg
 

skybluealan

Well-Known Member
Nick looks like you have a lighting loop-in system. The three reds should be connected together (live) You must as someone has said get a tester and find out which black goes to the switch. Then the other two blacks with the new lighting cable (blue) should be joined together. The Black from the switch and the new cable (brown) should be joined together. All green/yellow joined together. Hope this helps.
 

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