which cable is which ?

[cyberdyne]

With reference to the above post and diagram - which ive found very helpful;

I have 3 grey wires hanging from a ceiling, each of which has 3 cables within it; red, black and earth (also black but different casing - and all 3 wound together).

Im trying to replace a ceiling rose / light,etc, but am unsure how to tell which cable is which. ie: a)cable from previous light in chain, b)cable to next light, c)cable to switch.

Is there any easy way to tell them apart please?

*note, the building is an old concrete structure with no access to cables other that at the rose / switch / fuse box, etc.

Thank you.

 

[Steve]

cable to switch - easy. turn power off, take your multimeter, and measure the resistance across each red-black in turn. When you find the one whose resistance varies from zero to infinity when the switch is flicked, you have found the switch wire.

 

[cyberdyne]

cable to switch - easy. turn power off, take your multimeter, and measure the resistance across each red-black in turn. When you find the one whose resistance varies from zero to infinity when the switch is flicked, you have found the switch wire.

cool, going to try that.
thank you

 

[cyberdyne]

cable to switch - easy. turn power off, take your multimeter, and measure the resistance across each red-black in turn. When you find the one whose resistance varies from zero to infinity when the switch is flicked, you have found the switch wire.

Ok, great.
After finally finding a spare battery (well, cannibalising my smoke alarm - yes, ive replaced it, lol) and changing a spent fuse in my multimeter, ive found the switch cable.

Now, does it matter which cable I assume is the 'previous' and which is the 'next'? Will it cause any problems if I get them the wrong way round?
Presumably, going by the diagram, it wont matter?

Thank you for you help

 

[Steve]

No it doesn't matter. Glad my advise was of use to you! Always nice to hear a happy ending, and that not all DIYers are clueless with electrics!

 

[toasty]

It doesn't matter.

 

[cyberdyne]

It doesn't matter.

All done and working well.
Looks a treat

Thanks very much to all for your help once again

 

[cyberdyne]

....with regard to this same install;

I want to add a second light to the same switch if possible.

ie: add a second cable / shade / bulb to the existing ceiling rose.

Is there a specific splitter box / bracket / attachment which can do this or would having two lights from the same rose not be a good idea? (they are 25watt bulbs only)

Thank you.

 

[RF Lighting]

I couldn't quite work out from your post wether you are wanting to wire an extra ceiling rose from the existing one, or if you are wanting to have two flexes coming out of the existing rose. Please let us know so we can help you further.

Rob

 

[cyberdyne]

I couldn't quite work out from your post wether you are wanting to wire an extra ceiling rose from the existing one, or if you are wanting to have two flexes coming out of the existing rose. Please let us know so we can help you further.

Rob

Thanks and apologies for not making it clear.

I want the latter; two flexes from one rose, if possible.
Each flex would have just the one 25watt bulb, but id also need a spacer of some sort to keep the two (glass) shades apart.

*extra info:
the ceiling is concrete and pretty much un-drillable (is that the word?).
anyway, thats why im trying to run two flexes from one rose.

Thank you.

 

[RF Lighting]

I have never come across anything that allows two flexes to be connected to the same ceiling rose. I would think the best solution would be to fit an extra ceiling rose next to the existing with a bit of mini trunking between both. The concrete should be drillable? with a decent SDS drill which nowadays cost not alot and is a superb addition to your tool kit.

Rob

 

[securespark]

Can't you feed both flexes into the one rose?

 

[Steve]

Was going to say - you see them do this in pubs - if you can get 2 flexes from one rose, fix a hook in the ceiling where you want the other light to hang

 

[cozycats]

sorry to spout the regs but they say only one pendant per rose unless spefically designed for more!