Wiring a bathroon ceiling light, switch wire issue

[McGraw]

Hi.

I'm currently replacing a few ceiling lights in my house and all is well apart from the bathroom.

The old set up was a complete mess and tangle of wires but foolishly I got rid of it all before photographing it as the new light fitting is different and I thought it wouldn't be relevant.

Anyway, here's what I'm currently looking at which I can only wire to permanently on as I have no idea what to do with the switch wires.

Untitled

• McGraw
• 26 Jan 2014
• 1

As you can see, I have a switch wire with two reds and a bare wire.

Can anyone tell me how to wire this?

Cheers.[/img]

 

[EFLImpudence]

//www.diynot.com/wiki/Electrics:Lighting-Circuit-layouts

 

[McGraw]

//www.diynot.com/wiki/Electrics%3ALighting-Circuit-layouts

Thank you, however this part:

"It’s very important to keep track of which is the switched live because it will almost always be black (or blue), not the usual red (or brown) used for live, because normal twin and earth is red & black (or brown & blue). If you connect all the blacks together you’ll have a dead short between L & N when you turn the switch on and things will not go well for you."

Is making me think twice before connecting anything as I have two reds and bare wire on the switch wire.

As I am ok to the point that the light actually works (albeit permanently on) does this mean any mistakes wiring the switch up will not be disastrous?

 

[EFLImpudence]

"It’s very important to keep track of which is the switched live because it will almost always be black (or blue), not the usual red (or brown) used for live, because normal twin and earth is red & black (or brown & blue). If you connect all the blacks together you’ll have a dead short between L & N when you turn the switch on and things will not go well for you."

Yes, but you have twin red switch wires, an example of which is in the diagrams.
It doesn't matter which is which of the two reds.

Is making me think twice before connecting anything as I have two reds and bare wire on the switch wire.

As I am ok to the point that the light actually works (albeit permanently on)

That's because you have connected the lamp live to the loop lives and not the switched live.

does this mean any mistakes wiring the switch up will not be disastrous?

As long as you do not connect any reds to blacks.

 

[McGraw]

Ok thanks, I'll wire it as is shown for the living room light switch and if it doesn't work, swap the switch reds round.

 

[McGraw]

Ok one last check of something before I go ahead...thanks for your help so far, very much appreciated.

You can see from my pic that one of the switch wire's red cables looks like it hasn't been stripped back (and therefore used) yet the bare wire looks like it could have been.

Is there anything here to alarm or should I just strip back the red and use it?

 

[McGraw]

Ok I've just checked and the switch wire is red, black and bare.

Worried now that one of those reds is actually a black now.

What do you think?

Cheers.

 

[EFLImpudence]

Oh dear.

Can you determine where the twin red goes?
Was it definitely connected before?

 

[McGraw]

I think it must go into the bathroom mirror light so I guess I need to see what happens in there.

I honestly have no recollection of how things were wired before other than with a few junction boxes.

 

[AndyPRK]

There's a black that's not connected. Is that the switch wire?

Does the mirror light work at all?

 

[McGraw]

Ok here's behind the mirror (if I break the circuit at the ceiling, this light doesn't work anymore)

The mirror light is controlled by a pull cord.

Untitled

• McGraw
• 26 Jan 2014
• 1

There's no black wire that isn't connected, just two reds and a bare but the wiring behind the switch itself is red, black and bare.

Cheers

 

[AndyPRK]

I think you need a meter to test the red pair.
Turn power off
Set meter so is buzzes when probes touched together.
Connect them up to the red pair.
Pull switch cord
Does buzzed start/stop when cord pulled?
If yes it's the switch wire and its been joined.

 

[EFLImpudence]

Regarding the mirror light picture - (it looks as if) the wires are the wrong way round.

It may not matter but would be best to reconnect, red to brown and black to blue.

Oh, and the CPCs (earths) should be sleeved and joined.

 

[McGraw]

I think you need a meter to test the red pair.
Turn power off
Set meter so is buzzes when probes touched together.
Connect them up to the red pair.
Pull switch cord
Does buzzed start/stop when cord pulled?
If yes it's the switch wire and its been joined.

Thanks.

However, the mirror light is fine, the only thing I can't get working (or even try yet) is the ceiling light. Should I just do the same as you said but test by flicking the wall switch and not the pull cord?

 

[McGraw]

Regarding the mirror light picture - (it looks as if) the wires are the wrong way round.

It may not matter but would be best to reconnect, red to brown and black to blue.

Yes, they are wired as you think, well spotted.

Everything was fine before I pulled down the old light, think I will leave for the time being.

Cheers.