What's wrong with my 3gang switch?

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I've just changed a 3gang 2 way switch, and thought I'd copied the wiring from the old one, but it's not working right. Switch one works fine. Switch two also works fine, but switch 3 only works when switch 2 is on. The old switch had a short wire connecting the commons on switch 2 and switch 3. That is the only connection between the two but if I take that out neither switch works. I must have got something wrong somewhere, but can't work it out.

I'll draw a diagram of how it is wired and put it on here tomorrow, but if anyone knows what I've got wrong then any advice would be appreciated! Thanks
 
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sounds like you have the input and outputs the wrong way round on switch 2.

How many wires in switch 2 apart from the link and what terminals used in switch 2
 
What odds shall we give on the old & new switches having different terminal layouts or labelling?

Enthusiasticamateur - are the switches different at the back, e.g.:

screenshot_69.jpg



Do they both have the same markings, i.e. both C/L1/L2 or both L1/L2/L3, or are they different?
 
They are both like the one on the right, but one is upside down. I didn't just rewire like for like e.g.Top right to top right, I thought I had labelled where each wire had come from and made sure it went in the right place on the new switch but something has obviously gone wrong!

Each switch has a com terminal at one end and L1 & L2 terminals at the other. There is a wire going in to com and L1 on each switch, and a short one connecting the com terminals on switch 1 and switch 2.

Let's make sure my understanding is right - each switch should have a live wire that powers the lights going into the com terminal, and then the switch wire that goes to the light itself coming out of L1, right? When the switch is in the on position the com and L1 terminals are connected and the lights have power.
 
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Let's make sure my understanding is right - each switch should have a live wire that powers the lights going into the com terminal, and then the switch wire that goes to the light itself coming out of L1, right? When the switch is in the on position the com and L1 terminals are connected and the lights have power.
Some do wire them differently, but I use the method above, your original post stated you have a 3 gang two way switch. I assume by the information given that it is not being used as a two way function.

To correctly install/replace this you will require to confirm which cable is permanently live, this would be by test using a two pole voltage indicator.
Once you have identified perm live, that can either go to com of g2 or g3, then a link between that and the spare/empty com of either g2 or g3.
Then the switch live cables can go to L1 of their respective gangs.
If the switch fails to operate, test that you have voltage at coms of each and then with switch closed(on) on both gangs, then check that you have voltage at both L1s.
If either gang shows no voltage then you may have a faulty switch contact. You could try swapping the switch line to L2 to see if that works, and/or test for continuity between the switch contacts at com and L1/L2.
If 240V is present then you need to be looking further downstream for a fault, could be blown lamp(s) (AKA bulbs but not the garden type). Or a faulty transformer, loose connection or damaged conductors.
 
Thanks a lot, I've just realised that it is a bit more complicated as there is another single light switch piggybacking off of the 3 gang switch - only found this out as it s function is also dependent on the position of switch 2 on the 3 gang! Now I know the logic for how the circuit is supposed to work, and I think I know what the switch is supposed to be controlling I should be able to work it out.

Do I need a multimeter to test for the live or can I do it with an electricians screwdriver (the type with a lamp in the end)?

Thanks
 
A multimeter, at least, is an essential tool to have if you want to work on your electrics. It is just as important to have that correct tool as it is to have screwdrivers to use on screws instead of the point of a vegetable knife, wirecutters to use instead of nail scissors, wirestrippers to use instead of teeth, and so on.

Neon screwdrivers are questionable from a safety POV as they use your body as a current path, and they are unreliable - to safely check for voltage you must use a 2-pole tester, such as a proper voltage indicator or a multimeter.



This looks ideal for a household starter set - multimeter, voltage indicator and dedicated continuity tester, all in a handy case: http://www.amprobe.eu/de_DE/showproduct/115/Junior-Set/

PDF brochure: http://www.amprobe.eu/de_DE/downloadfile/115/beschreibung_1/

All in German, unfortunately, as is the blurb on each product:

Multimeter: http://www.amprobe.eu/de_DE/showproductdata/487/Hexagon_55/

Voltage indicator: http://www.amprobe.eu/de_DE/showproduct/1672/2100-Alpha/

Continuity tester: http://www.amprobe.eu/de_DE/showproduct/481/TESTFIX/

but it should be available in the UK - the company is now owned by Fluke, contact them (http://www.fluke.co.uk) for info on where to buy.

If not, there are sellers in other parts of Europe: https://www.google.co.uk/search?q=amprobe+("junior-set"+OR+1333)

Right now the English specs are still lurking on the Internet Time Machine from when Beha was an independent company:

http://web.archive.org/web/20060920022629/http://www.beha.com/files_uk/multimeter/93549.pdf


Also see another discussion here: //www.diynot.com/forums/viewtopic.php?t=26282 It's a few years old, so specific model number advice may be obsolete (and prices will be higher), but the generic advice is still sound.
 
Ban, you must be proud. You have found someone on here trying to change a light switch who actually understands how a light switch works in a house. :LOL:
 
Got myself a multimeter and checked - you were all right - live and switch were the wrong way round on g2. Could have sworn I checked that but I guess not!

Thanks for all your help and for not being too patronising!
 

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