extra wire in light switch

[lisa531]

I have just been replacing some light switches - nice simple task I thought until it came to replacing the two way light switch for the landing.

In the original switch, the red from the lighting circuit was not connected to anything and a separate piece of red wire was connecting two of the points (unfortunately I didn't note which ones). The rest of the wires were all connected in the traditional way. I replaced the switch and just wired as should be with the live connected and not using the separate wire.

In the second switch in addition to the wires from the switch cable there is also an additional black wire connected to the COM terminal.

With this second black wire disconnected nothing works, when it is connected the lights switch on and off but aren't working properly. they do something like the following:
both switches in same position - light off
switch downstairs - light on
switch upstairs - light stays on
switch downstairs - light stays on
switch upstairs - light goes off

All a bit confusing.

Any advice on what might be happening and how to fix it appreciated

 

[Taylortwocities]

unfortunately I didn't note which ones)

Tricky without being there. There's several ways that this may have been wired.

Can you take a photo of the switches both downstairs and upstairs and post them on here>??

 

[ColJack]

as you say "2 of the points", can we assume that one of the switches is a 2 gang switch?

with the com's linked?

pictures would help lots..

 

[lisa531]

Thanks for the replies, i've taken some photos to see if it helps.

Downstairs switch

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• lisa531
• 3 Oct 2009
• 1

This was originally a double switch but one of the switches did nothing so I thought i would change to single switch.
Correction from first post - the Red wire that wasn't connected was the one from the two-way switch cable

upstairs switch

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• lisa531
• 3 Oct 2009
• 1

Each switch has inside COM, L1 and L2 terminals.
The original downstairs switch had 2 sets of terminals

Upstairs light

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• lisa531
• 3 Oct 2009
• 1

The switches also switch on a second light further along the landing, I presume these are a spur from the ceiling rose

thanks

 

[ColJack]

try the single black in with the red.. let us know what happens..

 

[ban-all-sheds]

Why didn't you just use your multimeter to identify which wires were which?

 

[Taylortwocities]

multimeter? what multimeter. Every home should have one but, do they?