confusing lamp conection in ceiling rose

[paulgault]

Hi, i'd appreciate some advice on the wiring in the ceiling roses in my bathroom as i can't figure out how they're wired up as they don't seem to be wired up in the normal way!

i've done a few electrical courses but i don't work in the industry.

i'm doing my bathroom and have got some new fittings for it i'm going to replace the existing ones with.

it looks like the bathroom used to be 2 separate rooms (bathroom and toilet) that have been knocked into one. presumably it used to have 2 lamps with independent switches but now it has just one (SP) switch controlling both bulbs.

when i first took the cover off i was a bit confused as the lamps appear to be connected between the live feed and the switched wire and are not connected to the neutral. this didn't seem to be right so at first i thought there was a polarity issue, with one of the red blocks actually being the neutral.

i've got a decent voltage indicator that i've used to check for a voltage between all the connectors and the results aren't making any sense.

they've got the 3 standard connector blocks in it.

-on the left are 3 black and 1 red wire. there's no voltage between these wires and earth when the switch is in both positions so i've assumed this must be the neutral, but there is no connection between here and the bulb.
-the middle has 2 red wires (and another to the bulb). there is a voltage between these and earth when the switch is in both positions.
-the right has 1 red and 1 black wire along with another to the bulb. these have voltage between them and the earth depending on the switch

here's what it looks like



there are 4 twin core and earth coming into the ceiling rose. presumably the feed in, the feed out, one to the switch and another to the other lamp.

does anyone know what is going on here. help would be very much appreciated

thanks

Paul.

 

[Deleted member 9648]

I think you need to disconnect that lot and test each cable individually.
Identify the incoming L/N....the switch pair....the L/N loop to the second light...and any feeds out.......once you've done that you can start again.

 

[Johno]

I would have thought the same mate, but this obviously aint the case, you need to work out what each cable is and where it's going.

 

[paulgault]

nice one guys. the wife suggested re-wiring it like it should be but i was a bit hesitant as i didn't want to go messing with it if it's wired up in a different way than i'm used to. looks like i'm gonna be crawling round in the loft this weekend trying to figure out what cables are what!

was prodding it again with my voltage indicator and the lamp doesn't light when there's a voltage between the switched wire and earth, but it does light up when there isn't a voltage there!

 

[rodney12]

Is the light currently working corectly? seems a strange one

 

[Des 56]

It seems both lamps are being fed from the center connection,permanent live
The neutral is being switched using a red + black,black down to the switch and red returning to the neutrals on the left connector

Left hand connection would be 3 black neutrals and a red switch return
Center would be 2 permanent feeds to the lamps
Right hand would be a black switch wire and a red to the other light


Scrub that,rip it out and start again
It would be handy to see the conductor pairings with another photo

 

[jase]

you say ceiling roses, is there another one then, where it used to be 2 rooms?, have you a pic of the other one?

 

[telectrix]

looking at the photo with my glasses on, i would say that Des has got it spot on. i would definitely alter this so as the live is switched.looks like you can see which are the permanent lives ( centre terminal) and the switch wire appears to be the red/black across the lamp blue and the common neutral.

 

[paulgault]

it works fine at the moment in that it turns on and off when you flick the switch, but it doesn't look kosher though.

so the neutral is being switched! thanks Des!!!

here's a pic of ceiling rose 2, which was seriously ancient with a silly amount of paint over it. it didn't want to come off until it was ripped of and crushed with mole grips and the odd blow from a hammer here and there.



there's three black wires connected together, 2 red (also connected) and a single red. the lamp was connected between the pair of reds and the single red.

i'm deffo gonna scrap it and start again. am still baffled as to how this even works though!!

 

[pushrod]

nice one guys. the wife suggested re-wiring it like it should be but i was a bit hesitant as i didn't want to go messing with it if it's wired up in a different way than i'm used to. looks like i'm gonna be crawling round in the loft this weekend trying to figure out what cables are what!

!

Isolate the circuit, separate all the cores put reds into separate connector blocks, re-energise and use your voltage detector to work out the live feed.
De-energise.
Get a wander lead (a length of wire that will reach between roses and switch and croc clips or even connector block again would do) and a cheap resistance meter, with a few continuity tests you should be able to work out what is going where without crawling around in the loft. Mark them up as you discover which is connecting to which then just sleeve it up properly when you reconnect it all.