2-way switched ceiling rose

[HazzaMac]

In my haste to fit a new ceiling lamp, I removed the old ceiling rose and didn't make a note of the wiring. I have read up on how to identify a switched live (power off & use a multimeter etc) As you might expect, the switched live wire is not identified with a brown sleeve. My question is... why is there an extra, single blue wire going to the ceiling rose?

I have 3 sets of 3-core wires at the ceiling, all colored blue, brown & yellow/green, so I know what they are. It's the single blue wire that is confusing me.

Thoughts?

 

[JohnW2]

In my haste to fit a new ceiling lamp, I removed the old ceiling rose and didn't make a note of the wiring. I have read up on how to identify a switched live (power off & use a multimeter etc) As you might expect, the switched live wire is not identified with a brown sleeve. My question is... why is there an extra, single blue wire going to the ceiling rose? .... I have 3 sets of 3-core wires at the ceiling, all colored blue, brown & yellow/green, so I know what they are. It's the single blue wire that is confusing me. ... Thoughts?

From afar, we can but guess, but it may be 'neutral feed' to something else (which needed neutral, but didn't have one available.

Is that single blue wire perhaps connected to one (more likely two) of the blues in the three other cables (probably the ones which are not the switched lives)?

Kind Regards, John

 

[HazzaMac]

I'll snap a pic tomorrow, but it's a single blue wire 'exposed' out of a 3-core grey wire, presumably the other 2 wires were cut short and have never been wired in.

Thanks for the quick reply, though.

H.

 

[JohnW2]

I'll snap a pic tomorrow, but it's a single blue wire 'exposed' out of a 3-core grey wire, presumably the other 2 wires were cut short and have never been wired in. Thanks for the quick reply, though.

You're welcome.

What you say could be consistent with the 'guess' I offered. Since most people don't have cables with just a single core to hand, if they wanted/needed just a blue, they would probably use a 3-core cable and 'cut back' the two they didn't want/need.

Are there any light switches in the vicinity which have been changed to dimmers, 'smart switches' or any other sort of 'electronic' switch ('touch' switches etc.)? A good few of those require a neutral, but neutrals are not commonly found at light switches, so one has to 'get one' from somewhere else - a ceiling rose being one possibility.

Kind Regards, John

H.

 

[HazzaMac]

This is the wiring situation. I've used a multimeter and am pretty sure I've touched every possible combination of brown & blue, in that I keep one probe in a brown then sequentially touch each blue, then repeat the process with each brown wire.

There are 2 switches controlling the light and I've flicked them into all 3 combinations... I get no reading. When I touch the probes together I get a result, so I'm sure the meter is working...

 

[HazzaMac]

For reference, I had a look at the wiring arrangement in another ceiling rose that feeds into the room I'm having bother with. This, too, has 2 switches controlling it but one less blue solitary wire.

 

[RandomGrinch]

There are 2 switches controlling the light and I've flicked them into all 3 combinations.

As JohnW2 has said above...

Are there any light switches in the vicinity which have been changed to dimmers, 'smart switches' or any other sort of 'electronic' switch ('touch' switches etc.)? A good few of those require a neutral, but neutrals are not commonly found at light switches, so one has to 'get one' from somewhere else

Could you provide a photo of the wiring to the back of the switches, just so we can rule out possibilities?

 

[EFLImpudence]

This is the wiring situation. I've used a multimeter and am pretty sure I've touched every possible combination of brown & blue,

The rose shows two brown wires as the switch wires, try brown to brown when operating the switch(es).

 

[terryplumb]

Your pic of loose cables coming out of the ceiling appears to show 2 single browns( with earths) as well as a single blue conductor ( with no earth) is that so ?
You told us earlier that the single blue wire is from a cable with other conductors cut off ,but it doesn't appear to be so ,unless the pic is deceiving ?