Wiring of a two way light fitting..

mrbios

mrbios

mrbios

Soldato
Joined
7 Jun 2003
Posts
16,128
Location
Gloucestershire
Hopefully there's some DIY savvy or leccys here that can help me :)

Just had my missus dad here taking his old light fittings out and putting in the old ones as he rents this house out to us and wanted his ones back, not a problem except he's forgotten how to wire this light fitting back up again.

Looking at this, going by the internet diagrams my only thought is that the black wire should be wired into the neutral and not the live but obviously i don't want to do anything without someone telling me I'm right or wrong so please take a look at the picture below and tell me where this is wired wrong:

33totb9.jpg


It's possible the red cables are in the wrong place too as he just put them back in there to tuck them away from the time being.

Help :D
 
***** disclaimer ***** I an not an electrician :)

stating the obvious here but the N for neutral and L for live are clear in that picture.

Sensible advice if he has changed any other light fittings be prepared for a bang when you switch them on too :D

Haven't done one of these in my house for a while so can't remember how to wire it up , sure someone will tell you shortly.
 
Apparently in old wiring (to be honest i never wired anything in the "old" style) black is neutral, which is why i assume that he put the neutral in the wrong place here.... don't know where the reds should go though, they've both in the "loop" section at the moment
 
Em3bbs said:
You need to get a multimeter to be honest so you can work out which one the switched live is. Also you have nothing connected to the neutral.

Have a look here:
http://www.ultimatehandyman.co.uk/diy/electrics/light_fitting/ceiling_rose_wiring.htm
Click to expand...

The 3rd image down in that link looks exactly what i'm after......except i'm missing one of the black wires, i have 2 reds, and only one black o_O

EDIT: "or the lights could have been wired with the neutral wire in the switch" does that sound likely in that case?..... if that's the case then it's actually wired correctly
EDIT2: ah or it's the bottom one, in which case i should be able to tell by taking the two switch fittings off and seeing what cables are connected yes?
 
Last edited:
Even more confused now, just had a look behind the two switches and i've got 3 red cables in to one and 2 red + 1 black on the other.
 
http://www.diynot.com/wiki/electrics:lighting:two_way_lighting

Helpful diagrams showing multiple ways of wiring it all up including visualisation of cables.

Do you have a multimeter available? If so, it may be worthwhile knocking off the juice, labelling up all cores with an arbitrary numbering system, taking a photo of how they are terminated then disconnecting it all then continuity (polarity with battery) testing to work out what goes where then re-wire as necessary. If it all goes t*ts up then rewire back to how you found it. Obviously just take precautions when livening things back up.

P.S I'm not an electrician, I'm just describing what I'd do in your situation.
 
there should be six wires coming from the ceiling, and I can only see five and the there's no neutral return from the bluewire? It could be wired neutrals to the switch. The black isn't necessarily a neutral it could be a switch live normally indicated by tape or sleeving but not in this case.

If there is 3 red's into one it could be wired so theres a live and the others feed other light circuits in the house. is there two lights on that circuit or just the one ceiling rose?
 
Last edited:
daz87uk said:
there should be six wires coming from the ceiling, and I can only see five and the there's no neutral return from the bluewire? It could be wired neutrals to the switch. The black isn't necessarily a neutral it could be a switch live normally indicated by tape or sleeving but not in this case.

If there is 3 red's into one it could be wired so theres a live and the others feed other light circuits in the house. is there two lights on that circuit or just the one ceiling rose?
Click to expand...

Just the one cieling rose, my thoughts follow the same pattern in that there should have been 6 wires, which is what has me so damn confused :p

Annoying thing is my missus dad took the ceiling rose that he took out away without comparing the way that was wired to the one we're putting up....would have helped to have seen how it was done previously.
 
Power off, Black into neutral (blue), Reds into live (brown). Power on and see if it switches.

If it switched before then this is pretty much the only way it could be wired to work. (unless someone randomly took a live feed to the rose for no reason)
 
Last edited:
You need to find which cable is the feed, and which is the switch line.

Power off, multimeter both cables and turn the light switch on and off and you will get a reading on either cable. (this will be the switch line) the other shall be the feed. Then just Phase to Phase on both cables, feed neg into neg, switch line Phase into light phase.

btw it looks like you are missing a wire from one of those cables, ie the neutral from the right hand cable. not T&E cable, they probably used the cpc as the neutral :O
 
That looks a mess and i wouldn't keep using that without sleeving it properly first. Whats meant to happen here is..

Live feed into loop in centre, Feed out of loop block(centre) to switch (or set of switches), feed into live side were the the brown is ( for live on lamp ) and then a neutral back to distribution. The Neutral should NEVER be switched. In this case you seem to be a wire short.. Might be a good idea to get a multimeter out and test which are live when you operate the switch.

And as above, That would be a single core & cpc. I want to meet the dodgy electrician who installed this.
 
Last edited:
ZG002 said:
Looks like single core and cpc to me.
Click to expand...

at a second glance I now see it as a single core and cpc as well.

In the light switch what is the single core and cpc (if this is the case) connected to then I guess? L1, L2 / C or in a connection block?
 
Last edited:
Thanks for the help chaps :) Will bring a multimeter home from work tomorrow to get it sorted.

No doubt i'll be back in here when i fail :p
 
bitslice said:
Only if in America ;)

I wonder how many houses burn down in the US, everything about their wiring system is awful.
Click to expand...

Everything ?

They use a much safer voltage 120v (admittedly that means 2x thicker cables are needed to carry the same current)
They also believe that ring finals are fundamentally flawed and unsafe something which as a qualified electrician (16th Ed.) I completely agree with.

As for the O.P, as stated you need to identify the switch phase, this can be done very quickly and safely with the system isolated (switch OFF at the C.C.U)
Simply open up the switch that controls this light and connect the common & L1/L2 together, now using a DMM at the ceiling rose id these cables using the continuity setting .
 
C.R.A.Z.Y said:
Everything ?

They use a much safer voltage 120v (admittedly that means 2x thicker cables are needed to carry the same current)
They also believe that ring finals are fundamentally flawed and unsafe something which as a qualified electrician (16th Ed.) I completely agree with.

As for the O.P, as stated you need to identify the switch phase, this can be done very quickly and safely with the system isolated (switch OFF at the C.C.U)
Simply open up the switch that controls this light and connect the common & L1/L2 together, now using a DMM at the ceiling rose id these cables using the continuity setting .
Click to expand...

Op do not start to take connections out of the switches, if they switched fine before leave them, you will get the same effect if you simply switch the swich on and off. You would be in for a head ache if you started mixing up you connections at the switches.
 
C.R.A.Z.Y said:
Everything ?

They use a much safer voltage 120v (admittedly that means 2x thicker cables are needed to carry the same current)
They also believe that ring finals are fundamentally flawed and unsafe something which as a qualified electrician (16th Ed.) I completely agree with.
Click to expand...

Some circuits use a mixture of 120v and 220v I think, I'm assuming that's just adding a second phase.
Rings mains, perhaps, although it does save a shed load of copper and it's more logical to wire. Radial is overkill.

But those light switches are nasty, exposed terminals on all sides!? No wonder you see it wrapped with insulation tape afterwards. And botch-a-joint twist on connectors, meh, they were never reliable as a networking connection either.
UK stuff is fundamentally better designed, I've yet to see a US panel and think 'tidy job', I've seen tidier network cabs.

And colour coding, black as hot? Who came up with that?
 
You must log in or register to reply here.
Back
Top Bottom