Ceiling Light Problem

terenurebob · 23-07-2011 8:50pm #1

Hi all. I have a ceiling light that is not working. I took off the light switch and on the back of it are 3 connections. They are labled L1, Com and L2. There is a brown wire connected to the Com and another brown wire connected to L1. There is no wire connected to L2. I took a voltage tester, a screwdriver with a small light in it, and touched the L1 connection and the voltage tester light comes on and I touched the Com connection and the voltage tester light did not come on. I then turn the light switch on and when I touch the voltage tester to L1 the voltage tester light does not come on and when I touch the voltage tester to Com the voltage tester light does not come on. I have checked the light switch by using it on another light and the switch itself is working. Anybody have any ideas of what else I could check? I did touch the voltage tester to the wires in the ceiling light and the voltage tester light did not light up.

meercat · 23-07-2011 8:56pm

have you replaced any other switches or light fittings lately

terenurebob · 23-07-2011 9:02pm

No. The light hasn't work for a couple of years and I am only trying to fix it now.

meercat · 23-07-2011 9:08pm

my guess is the bulbholder
see can you access the ceiling rose and check connection here
(phase tester although not ideal will light up when checking for live wire here)

http://sweier.en.made-in-china.com/product/UqBJLgibvnIY/China-Ceiling-Rose-Lamp-Holder-A200-.html

connect the wires you have at the switch in a connector block to be sure its not the switch at fault

REMEMBER
turn off power when working on it

terenurebob · 23-07-2011 9:14pm

I checked the live wire at the ceiling rose and the phase tester did not light up. I touched the phase tester to the brown wire in the ceiling rose. This is the same brown wire that goes directly back to the light switch.

I have used the light switch on another light and the light switch works.

meercat · 23-07-2011 9:20pm

remove bulb from affected light
join the cables at the switch
check that the phase tester lights up on them
then check does the phase tester light up at ceiling rose

(a phase tester is not ideal for checking for 230volts though)

terenurebob · 23-07-2011 9:21pm

Thanks. I will try that and see what happens.

terenurebob · 24-07-2011 8:21am

I took out the light bulb, connected the two wires together and the phase tester lights up when I touch the brown wire at the ceiling rose. I put the wires back in the switch to do some more testing. I have left the light bulb out for this testing. Once the brown wires were back in the switch correctly I touched the phase tester to the brown wire in the ceiling rose and the phase tester light came on. I turned the light switch on and touched the phase tester to the brown wire in the ceiling rose and the phase tester light came on again. I would not have thought that the phase tester light would come on with the light switch in both the on and off positions. Does all of this point to a faulty ceiling rose?

pegasus1 · 24-07-2011 8:43am

terenurebob wrote: »

I took out the light bulb, connected the two wires together and the phase tester lights up when I touch the brown wire at the ceiling rose. I put the wires back in the switch to do some more testing. I have left the light bulb out for this testing. Once the brown wires were back in the switch correctly I touched the phase tester to the brown wire in the ceiling rose and the phase tester light came on. I turned the light switch on and touched the phase tester to the brown wire in the ceiling rose and the phase tester light came on again. I would not have thought that the phase tester light would come on with the light switch in both the on and off positions. Does all of this point to a faulty ceiling rose?

sorry but its time to contact your local electrician as electricity can kill if wired incorrectly...one of those wires will be a neutral..just that the electrician ran out of blue wiring...it shouldnt cost an arm and leg to get done these days..

terenurebob · 24-07-2011 9:14am

Just to be clear here, there is both a blue wire and brown wire connected to the ceiling rose. From what I understand, the brown wire is the electricity in (live wire) and the blue wire is electricity out (neutral wire). This is why the phase tester does not light up when I touch the blue wire.

meercat · 24-07-2011 10:56am

terenurebob wrote: »

Just to be clear here, there is both a blue wire and brown wire connected to the ceiling rose. From what I understand, the brown wire is the electricity in (live wire) and the blue wire is electricity out (neutral wire). This is why the phase tester does not light up when I touch the blue wire.

Replace bulbholder and flex
Again make sure power is off when doing this

terenurebob · 24-07-2011 11:38am

I have replaced the bulbholder, flex and the light switch. There bulb still does not come on. I have checked that the bulb works by putting the bulb into another ceiling light. Any other ideas of what I could check? Attached is an image of the bulbholder wiring. I do not know why there are two blue neutral wires but it was like that when I opened it.

pegasus1 · 24-07-2011 12:33pm

terenurebob wrote: »

I have replaced the bulbholder, flex and the light switch. There bulb still does not come on. I have checked that the bulb works by putting the bulb into another ceiling light. Any other ideas of what I could check? Attached is an image of the bulbholder wiring. I do not know why there are two blue neutral wires but it was like that when I opened it.

you have a broken neutral somewhere on the circuit....as i have previously said, call an electrician,

If you do not know why you might need 2 neutrals at the rose you have no business doing what you are doing!

terenurebob · 24-07-2011 12:46pm

Thanks pegasus1. I just wanted to make sure that it wasn't something simple that I was missing. I'll leave this one to the professionals.

jimmyw · 24-07-2011 7:38pm

I think you need to establish which of the wires at the light switch is live.Whichever one is connect this to L1.Then check to see if there is power at the L2 connection.Turn on the switch (dont connect any wire to L2) and see if there is power there with and without the switch on/off.I thought that L1 was power in, L2 power out, and com is the neutral wire.

Dont blame me if you shoot up through the ceiling

pegasus1 · 24-07-2011 7:45pm

jimmyw wrote: »

I think you need to establish which of the wires at the light switch is live.Whichever one is connect this to L1.Then check to see if there is power at the L2 connection.Turn on the switch (dont connect any wire to L2) and see if there is power there with and without the switch on/off.I thought that L1 was power in, L2 power out, and com is the neutral wire.

jimmyw, are you an electrician? it appears not by what you advised from the above

jimmyw wrote: »

Dont blame me if you shoot up through the ceiling

this is in no way disowning yourself from your advice..

jimmyw · 24-07-2011 8:02pm

Whats L2 for so? I didnt say to connect any wire to it, just a way of checking to see if L2 is switched? What would your suggestion be so?

I was joking about the last comment above.

brightspark · 24-07-2011 9:18pm

OP you are not going to be able to diagnose the fault with a phase tester.

From the limited information you have given I would guess a loose connection supplying the switch, but it's difficult to be certain.

jimmyw wrote: »

I think you need to establish which of the wires at the light switch is live.Whichever one is connect this to L1.Then check to see if there is power at the L2 connection.Turn on the switch (dont connect any wire to L2) and see if there is power there with and without the switch on/off.I thought that L1 was power in, L2 power out, and com is the neutral wire.

Dont blame me if you shoot up through the ceiling

Jimmyw that is totally wrong, are you trolling?

connecting power (live) to L1 and the neutral wire to COM would result in a short circuit.....VERY DANGEROUS don't do it.

I hope you arn't an electrician, and for you own safety and those around you stay away from mains wiring.

jimmyw · 24-07-2011 9:43pm

Where is the power into the switch then? And whats L2 for then? Very well used to home electrics and never blew myself up as you know by me posting obviously

.The proper way i would test the switch is with a multimeter on the resistance/continuity switch with it removed so no danger of shorts.Without actually having the switch in your hand, its hard to diagnose faults on an internet forum.I didnt say to connect up any other wire apart from the live wire to check what other terminal is live with the switch on/off, But I am not trolling.

meercat · 24-07-2011 9:55pm

may be a job for electrician op
here is a lighting wiring diagram for you if that helps
http://2wayswitch.com/multiple-light-points-wiring-circuit-diagram/

brightspark · 24-07-2011 9:58pm

@Jimmyw

A lot of light switches even if only used as one way are actually two way switches.

When used as a one way switch only COM and either L1 or L2 are used not both. (If you use the wrong one the switch is 'upside-down' when you use it)

For two way light switching obviously both L1 and L2 are used.

(Find a two way switch and using your meter check for continuity between COM and L1, and COM and L2, then operate the switch and note that the difference)

jimmyw · 24-07-2011 10:31pm

Isn't com going to the neutral? or is it going onto the next light bulb. Dont you need an in and out wire at the switch?

meercat · 24-07-2011 10:41pm

jimmyw wrote: »

Isn't com going to the neutral? or is it going onto the next light bulb. Dont you need an in and out wire at the switch?

com is the live connection in and loops onto the next switch and so on
its the red wire in this diagram
http://2wayswitch.com/multiple-light-points-wiring-circuit-diagram/

jimmyw · 24-07-2011 10:56pm

Ah well I stand corrected then:o.I thought it was neutral.I always check switches with a multimeter before connecting power to it.

pegasus1 · 25-07-2011 2:39am

jimmyw for your safety pls stay away from electrics....

jimmyw · 25-07-2011 2:42pm

I have fixed plenty of electrical appliances before so have no problem with them and have not caused any damage to myself or others or appliances.I do admit light switches are a little confusing but I am careful to make sure I put back things the way they were if I cant fix them.I always check things with power off first and check for continuity with a multimeter.I have my own way of doing things but maybe I might not be the best to describe to someone else.I never touch things with power on either so will continue to do so, thanks for your concern;):D.

Ceiling Light Problem

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