Spare Yellow?

[DavidHL]

Help!!!
I am replacing a ceiling light and have a spare yellow cable which does not appear on a normal circuit diagram. The 3 reds are joined together as are 2 of the blacks. The earths are also all joined which leaves a spare blue and the yellow. How do these 2 wires need to be connected to complete the installation?
The ceiling light is in the same room as 3 wall lights and all are operated from a 2 gang switch. I have replaced the wall lights but do not light up when the trip is switched back on.

 

[ETAF]

any photos
it sounds like 3 core cable - 3 cores and an earth - which maybe controlling various lights , separately or do you have 2 switches that control 1 set of lights

yellow, red, blue and bare earth

 

[EFLImpudence]

I am replacing a ceiling light and have a spare yellow cable which does not appear on a normal circuit diagram. The 3 reds are joined together as are 2 of the blacks. The earths are also all joined which leaves a spare blue and the yellow. How do these 2 wires need to be connected to complete the installation?
The ceiling light is in the same room as 3 wall lights and all are operated from a 2 gang switch. I have replaced the wall lights but do not light up when the trip is switched back on.

If the lights worked properly before then you should just copy the existing wiring and transfer it to the new light.

 

[plugwash]

The first rule with lighting circuits is don't disconnect anything without recording what is connected to. There are lots of variations of lighting wiring.

Do you know how the light was wired before?
How many cables are there at the light? how many and what-color cores does each cable have?
Can you look at how the switch is wired?

My best guess based on what you have told us so-far is that yellow is the switched-live, and blue is a neutral going down to the switch to feed the wall lights.

 

[ericmark]

I can only guess, but know when mothers house was rewired triple and earth used for all switch drops so either the neutral or two way switching could be set up latter without pulling through another cable, not connected just there ready.

 

[sparkwright]

Photos would be helpful here.

You mention spare yellow - and also spare blue.

Are they just wires going nowhere? Or are they doing something?

To have yellow and blue wires at the light fitting COULD suggest 2-way switching. Or perhaps 2 lights controlled by separate switches.

More detail needed, as I'm going to end making too many wrong guesses.

 

[securespark]

Could it also be a fan?

 

[DavidHL]

Thanks - photo attached. This ceiling light and 3 wall lights are controlled by 2 gang switch. This light only has one on/off switch.

 

[SUNRAY]

Help!!!
I am replacing a ceiling light and have a spare yellow cable which does not appear on a normal circuit diagram. The 3 reds are joined together as are 2 of the blacks. The earths are also all joined which leaves a spare blue and the yellow. How do these 2 wires need to be connected to complete the installation?
The ceiling light is in the same room as 3 wall lights and all are operated from a 2 gang switch. I have replaced the wall lights but do not light up when the trip is switched back on.

SO...
I've seen the photo...
Did you remove the ceiling light?
Were those connectors there when you removed the light or did you fit them?
What wires do you have at the wall lights?
Was the blue really spare (it looks like it has been connected somewhere)?
Was the yellow connected to the ceiling light?

Have you had a look behind the wall switch?