Help with weird light-switch wiring in living room

[carl0s]

Hi. I wonder if somebody can help us.

The light switches in our living room are strange. They have always been this way since we moved in a couple of years ago and I'm thinking somebody has simply wired up one of the switches wrong.

The room has two lights, one either side, with a corresponding switch on either side of the room.

The light on the RHS of the room only comes on if *both* switches are in the on position. The light on the LHS of the room is constantly on, and therefore doesn't have a bulb fitted because we can't turn it off.

I switched off the mains at the circuit breaker, and pulled off the faceplate from the LHS switch to have a look if there was some weird and wonderful complicated wiring going on behind there. All I found was that the switch has three wires, all red, and appears to be a two-way switch with L1, L2 and Common connections.

Does it sound as though somebody has put a two-way switch in where there should be a one-way switch (although there are three wires)?, or is it more likely that the switch is switching the common instead of the L1/L2 or something?

I am not building-electrical savvy and have no knowledge of how these things should be wired (L1, L2 etc. ?) but should have no problems following instructions if anybody could be kind enough to offer some advice.

thanks for your time.

regards,
Carl

 

[RF Lighting]

It sounds as if something is wired wrong.

Can you take a photo of what you currently have connected at both switches?

 

[carl0s]

Coming right up! Thanks for such a quick reply.

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Here they are:

This is on the side of the light which can't be switched off:

This is on the side of the light which is affected by both switches:

The fact that the two screws were left in the back of the faceplate might give some indication as to the competence of the person who fitted it

 

[Spark123]

Please can you confirm the common terminals are the top ones in the pictures?

 

[carl0s]

Yes. They look like this:

 

[carl0s]

Of course I am not sure whether the lights are meant to be independantly switched. It might be the case that they're both supposed to come on/off at the same time, with either switch, or it could be that it's supposed to be one switch per light. I have no idea.

 

[Spark123]

OK, it is just I have seen some new ones with the terminals in different combinations. Maybe a job for tomorrow, turn off the electric, label each wire where it is coming from and remove both switches. With a multimeter set to ohms range, check between com and 1way for each switch. Operate the switch and check it changes state. Do the same for com and way2. You should see continuity between com and way1 with the switch one way and between com and way2 with it in the other.
Can you also provide a few pictures of the wiring in the ceiling roses?

 

[carl0s]

I have a multimeter at my office so I'll test the switches tomorrow. Does a faulty switch fit the pattern of behaviour here?

It's strange, because I think in a normal two-way switch setup thingy, you can turn the light on/off with either switch, but that's not the case here - if one switch is off, then the other switch can't turn the light on, and vice versa - both switches have to be set to on, and this only affects one side. The other side of the room is constantly on.

 

[carl0s]

Can you also provide a few pictures of the wiring in the ceiling roses?

I can't right now, another job for tomorrow I think. Thanks for the help so far.

 

[Spark123]

I'm trying to get my head around how they could have been wired!! A faulty switch would fit the pattern if, and only if the two red wires which are part of the same cable are 2 way lighting strappers i.e. they go directly from one switch to the other. This doesnt go very far to explaining the other light staying on though.

 

[carl0s]

I was able to stand on the sofa and get a picture of the wiring into one of the ceiling roses.

This is the one that can't be switched off:

Anything seem unusual?

Hang on, I think with a chair I'll be able to reach the other one too..

 

[Spark123]

Yup, there are two red wires in the lamp live terminal. Will need further investigation tomorrow.
The flex wires need to go the opposite way around the cord grips too.

 

[carl0s]

Ah, I can see that. Normally the large group of live wires goes in the middle connection-block, right?

Anyway, here is the other ceiling rose - the side which does switch off/on:

 

[Spark123]

OK, I think after you have checked the switches you need to identifty what the 3 red wires in the first ceiling rose picture do. There is a problem in there as the light doesn't switch, you may find that the red on its own is a switched live, that is just a guess though. Is there a single red wire on its own cable in there?

 

[carl0s]

Ah, I see what you're saying. There doesn't seem to be any purpose to having that single red wire connected to nothing.

What I'll do is buy one of those glow-light screwdriver mains tester thingies (what're they called?) and have my girlfriend switch the lights while I test.

Is that a reasonable thing to do?