home wiring help - replacing light switch with 4 wires (2 red/2 black)

[wingers]

Hi
Hopefully someone can help me

Am replacing all the light switches in my house and have done them all without problem except this final one which is confusing me

The switch is a double switch but only one seems to do anything (kitchen fluorescent light), the other does nothing

It has 4 wires (2 red and 2 black), the 2 black go to two different common terminals and the 2 red go to two different L2 terminals

What type of switch is this and how do I replace it, as the new switches only have two terminals L1 and L2

This is the only switch for the kitchen light so it is not a 2 way switch or anything like that



photo attached which may help hopefully

Thanks in advance

 

[i=p/u]

maybe was two pendants up before , so extra switch wires

 

[wingers]

possibly, so how do I replace the switch, where would each wire go on a modern switch?

From trying to roughly trace the wires it seems one pair go to flourescent light and other pair go off to junction box fed from electrical source

 

[tony mc]

You really need to test the wiring to make sure it is actually dead.
With an approved voltage tester or simular not a neon test screw driver or volt stick.

It could be lots of reasons why it has been left in but bad practice by the person doing so.

Just because it does not switch anything on does not mean that it is not live.

You don't seem to have any CPC (earths) st the switch either.

 

[wingers]

no there is not earth (CPC) on any of the light switches - it is a 1965 built house which might explain why

It appears using a multimeter that both wires are carrying current?!?!

 

[Adam W]

Did the other switch ever do anything?
I'd be interested as to where they go, in fact I've got a mystery switch like that in my hallway.
A new switch will just wire up the same way.
If your new switch is metal remember to connect the earth wire - it looks like it's just been cut back which is a bit naughty.

 

[Deleted member 9648]

They are simply 2 separate 1way switches,I assume you are replacing it for a 1 gang as 2 gang switches are always 2way with 3 terminals on each gang.
If so you need to find which pair control the kitchen light and connect them to L1 and L2....The other pair are redundant if they do not appear to switch anything,safely blank them off with connectors and tuck them into the box out of the way.....I do not see any earth wires in the pic....If you are using metal plate switches or a metal box they MUST be earthed,if you are not sure GET IT CHECKED BY AN ELECTRICIAN.....no earth means high shock risk.

 

[Adam W]

I would advise against replacing the switch with a metal one then - just replace it for a similar plastic one.

 

[i=p/u]

youl need live comming from juction box to (com) on switch, then from (L2 ) on switch to light and you can terminate other ones in connector block. if youve no test equipment , just turn off all power in the house. if you can check what cable is going to light from switch , that should be in L2.. hope this helps ,,, remember all electricity off as could have borrowed neturals

 

[SirKit Breaker]

The switch you have in your photo is a 2 gang 2 way light switch. This is used to control 2 lights individually.
In your existing switch you have Common, L1 and L2, your new one has only L1 and L2, this is because it is a 2 gang 1 way switch. Put the Reds into L1 and the blacks into L2, but make sure you keep the right red with the right black, if the switch works upside down the swap over the relevant red and black. Tony is right to advise you to use the proper tools to test for dead, and you may find that the redundant cable is still live. I wont try and put you off doing the job, be just be careful, at least make sure the circuit is isolated even if this means turning the whole lot off. If the twin cables don't have an earth, then make sure you have no metal fittings of any kind on the lighting circuit. If you find cables at the switch that are live and redundant, then do what i do if it is not possible to remove them. Get a piece of 15amp connector block, cut the end off the live cable, leave it insulated and put it into the connector block, and put a note in the back box stating the cable is live.

Cheers....Howard

Regards...Howard

 

[wingers]

thanks for all your replies

just had multimeter out and looking at the photo the left hand side pair which go to common and L2 show 0v when light on and 240v when light off, the right hand pair which go to the other common and L2 show around 80v?! when switch is on or off

Now I am really confused

BTW it is a fluorescent strip light if that makes a difference?

 

[mogga]

CALL AN Electrician or put yout location n possably a forum member may be able to assist you

 

[Dunc]

No CPC on the light circuit and a fluorescent fitting in the kitchen, alarm bells ringing for anyone else with regards to the likelihood of an un earthed class 1 fitting?!

 

[wingers]

have arranged for an electrician to come and do a full check of all the electricals next week - as only just moved in a few weeks ago so think it would be money well spent to get it all checked

 

[Geordie Spark]

have arranged for an electrician to come and do a full check of all the electricals next week - as only just moved in a few weeks ago so think it would be money well spent to get it all checked

I agree.

That's very sensible of you.

 

[peck06]

Was that a wooden back box I saw in that photo too???

 

[wingers]

Was that a wooden back box I saw in that photo too???

i'm afraid so - all of the light switches in the house are like that

 

[peck06]

Wooden back box, no cpc, think you need more than a new switch plate. You should get someone in to do a T+I and be prepared for a long list of remedial works

 

[wingers]

Wooden back box, no cpc, think you need more than a new switch plate. You should get someone in to do a T+I and be prepared for a long list of remedial works

What is a T+I?

Hopefully that is what I am having done next week, got an electrician who is going to check over all electrics in house and do me a report, around £120 - £150 - does that sound right?

 

[i=p/u]

ive heard loads on forum say about £20 -£25 per circuit and that is qualified men and doing the jobs to best of their ability. and the way they talk they dont cut corners. so serioussssssssssss lol, and im only a learner with big L badge with 500v dc in my hands