changing a switch

[trumpy]

Hi hope someone can help.
I am trying to change an exsisting switch, its a three way switch ie it controls 3 sets of lights (hope thats the right terminology!)
the problem is that the backs of the switches differ, one has L1 L2 + L3 the other has L1 L2 + Comm, I have tried simply to use L3 and connect it to Comm. this doesn't work any ideas

 

[ban-all-sheds]

Hi hope someone can help.
I am trying to change an exsisting switch, its a three way switch ie it controls 3 sets of lights (hope thats the right terminology!)

No - that makes it a 3-gang, not a 3-way.

the problem is that the backs of the switches differ, one has L1 L2 + L3 the other has L1 L2 + Comm, I have tried simply to use L3 and connect it to Comm. this doesn't work any ideas

Yes.
1) Go and buy a multimeter.
2) Make a note of which wires go where on the existing switch.
3) Turn off the power, remove the old switch.
4) Use your multimeter to work out how the switch works, and which terminals are conected to which, and when.
5) Do the same with the new switch, then you will know which terminals are equivalent to which between the two switches
6) Install the new switch.
7) Turn the power back on.

This way you will accomplish your goal and start to gain knowledge of domestic wiring. If you are unwilling or unable to do the latter then please replace the original switch and call an electrician.

 

[securespark]

What brand is new switch?

 

[trumpy]

It was bought from B&Q finished in brushed chrome(I guess that bit doesn't help!!)

It is probably a silly question but why do they make them differently, surely having the same connection would make life so much easier?

 

[securespark]

These things were sent to try us.........

At a stab (DO NOT TAKE MY WORD FOR THIS) I guess that L1 is common, L2 and L3 are anybody elses L1 & L2. How are the terminals laid out and is there a brand name on the back of the switch?

BTW, I pity your partner with a name like trumpy!!

 

[il78]

You say it a 3gang but you have only mentioned Comm/L1/L2 & L1/L2/L3.....hows the 3rd one set up...?

 

[trumpy]

Hey take the mick out of my DIY skills or lack of them, pls leave my name alone!!! thankyou

As for 3 gang i may have my terminology wrong the switch has 3 switches (confused?) working 3 sets of lights. There is another different switch that controls one of the set of 3 lights and another idependent light
No brand name I'm afraid.

Now thats propably as clear as mud!!
OK anyone know a good electrician?

PS Trumpy is not my real name, now you would have fun if you knew that

 

[securespark]

Have you tried L1 as common and L2 & L3 as L1 and L2 on other switches?

 

[ban-all-sheds]

A 2-way switch has 3 terminals (so your 3-gang has 3 sets of these, but each set is completely independent).

Ignore COM, L1, L2, L3 etc, lets call the 3 in any set A, B and C. A will be connected to B or C depending on the position of the switch. B and C will never be connected together whatever the position of the switch.

With a meter set on low-range resistance or continuity it takes less than 30 seconds to identify which is which - it really isn't rocket science.

"A" is COM if your switch is labelled such.