2 switches, 2 lights, not working!

[Rachael]

I hope somebody can help me sort this out, I'm confused.

I have a 2 gang switch which is intended to operate 2 separate lights. Coming in to the box are 3 leads, all with 1 red and 1 black wire, (earths too but those are OK). the current wiring is that one red wire is connected to both of the COMs and each switch has a red wire connected to the out as well.

At the moment switch 1 only operates light 1 if switch 2 is in the on position. Switch 2 does not operate light 2 at all.

Can anyone help me understand what is going on.

Thanks,

Rachael

[Sparks]

Did it ever work correctly!?

I assume this is not part of a two way circuit (two switched operating one light, usually one upstairs and one downstairs for a landing light)

Do you have a multimeter so you can test things?

Assuming there isn't a two way arrangement, then I expect one cable (Red/Black/Earth) is a live feed, then the two others feed the light.

Are all the black wires connected to each other, but not the switch?

Sparks...

[Rachael]

It has been like this since we moved in, so Don't know if it has ever worked unfortunately. It isn't part of any two way arrangement, these are the only switches for these lights.

The black wires are all connected to each other, and not the switch.

I only have a screwdriver type thing that gives voltages, not a full multimeter, but can test for live with that.

Thanks,

Rachael

[The Natural Philosopher]

Ah. So two switches, and two lights..

Thats fine so far as it goes...

OK.

You need to disconnect all of the reds, and find the one that is permanently live.

That's the incoming mains.

The other two reds are, we hope, the live lines from the switches to the lights.

Each of those other two reds need to go to the L1 of each of the switches.

The common of the switches need to be linked together with a scrap piece of red wire, and to the incoming live.

[Rachael]

Thanks for that. I checked which was the live and it was one of the ones they had connected to L1, so have changed that now. Unfortunately Light 2 still doesn't come on, even if I swap round the switches, so it's not that. It must be the light fitting itself, which would explain the strange switching I got before. More investigations will have to wait the purchase of a longer ladder (high ceilings.)

Thanks very much for your help. Greatly appreciated

[Dave Plowman (News)]

Just a point - these two gang two way switches usually have one of the switches inverted, so look rather like this on the back.

com / L1 L2 / / / L1 L2 / com

With the dividing line showing which terminals refer to which switch.

I doubt it matters in your case but it has confused others before. ;-)

[Roger Mills (aka Set Square)]

Of the 3 red wires, one is the live supply and the other two should go to the lights, and should only be live when their respective switches are on. The live feed needs to be connected to COM on *both* switches. My hunch is that 2 of the reds have been swapped - so that the live feed is currently connected to the *output* side of one of the switches. This would require

*both* switches to be on for one of the lights to operate - but the other light should still operate with only one switch on - which it apparently doesn't. Are you sure you haven't got a duff bulb in one of the lights, to compound the problem?