2-way switch

[dogzdinner]

I am attempting to replace a 2-way switch system that uses only flat twin and earth but there are 3 cables involved meaning that at each switch there are 3 red and three blacks! The switches are quite old and the only terminal marking I can see is for the 'common' terminal . The two switches are double ganged (two switches on each switch unit). The back of the switch is marked 'top' and that's it! There is hall light and a landing light so obviously the idea is to turn the unwanted one off. Unfortunately the switch downstairs had the wires disconnected....... The switches are constructed as follows:
3 terminals (one of which is 'common') at the top the same again at the bottom.
The left hand switch connects the top common terminal to the terminal either side, depending on switch position and ditto the right hand switch to the bottom terminals.
On the switch that IS connected, the red and black from one wire goes to the common terminals (one in the top group of terminals connected to the left hand switch, and one in the bottom group connected to the right hand switch).
So, the red and black from another wire goes to the 2 bottom terminals and ditto the top.
I assume one of these cables is the live cable that supplies power to the circuit and the others are the switching cables.
Anyone understand my predicament and offer advice?

 

[andemz]

lost me on all of that but have you tried looking here

 

[securespark]

Just done some sketching and I think I've got it?

I have to make an assumption for this to make sense.

This is that the two switch positions both control the same lights.

Well, the cable that has one conductor connected to one common terminal and the other to the other is the live and switched feed for one of the lights (lets call it light A).

The feed is connected to one common (let's call it Common 1) which then (via the two conductors connected to the L1 & L2 associated with common 1) links with the one of the pairs of L1/L2 terminals in the disconnected end. with the switchwire of light B in the common terminal.

Similarly, the switchwire (of light A) which is connected to the other common (Common 2) in the connected end will link to the disconnected switch position via the two conductors associated with common 2. These will connect to the other L1 and L2 with the live feed in the common terminal.

BUT, you have to discover which cable is which in the disconnected end by using a multimeter set to continuity. With power off, temporarily disconnect one L1/L2 pair from the connected switch (making careful notes as to where to replace them!) and join them together. With the meter set to continuity, go to the disconnected switch position and test each pair of R & B to see if you get a buzz or continuity reading on the meter. When you do, that is the right pair. Repeat to find the other pair, and the remaining untested pair should be the live and switchlive.

Hope this makes sense....


I can't do fancy artwork.

 

[dogzdinner]

Thanks Securespark, will print it off. Did some sketching myself so will see if my dwgs match your narrative... The only problem with the old switches is that the terminals aren't marked. The other problem being that the wires at on end have been disconnected os will try the contiuity test to see which wires are which. I know I can eliminate two pairs at each switch as follows:
-1 pair will be to the light itself
-the other pair will be the main run that the switches switch between to, say, turn the downstairs light off/on when up stairs or to turn the upstairs light off/on when downstairs.

I asume the other pair at the top will be to suplly power to the upstairs light indepenfant of the 2-way system and ditto downstairs. Will let you know how I got on. I'm much more in tune wirh aircraft wiring!!!

Thanks also Andemz - went to the picture you linked me to but it's not quite the same case. My problem is that there are 6 wires (3 pairs) at each switch) but I think Securespark and myself have reached same conclusion. T

Thanks again to you both.

 

[dogzdinner]

For attention of Securespark: Hi again and hope you don't mind my pestering you! Am still having trouble with this 2 way switch system, namely not sure what wires are doing what. I have made a diagram of what I have found so far and compared it to what I thought I was hopng to find..... Do you have an email address so that I can send you the diagrams or can anyone enlighten me as to how I can post the piccys in the Forum for general comment? Thanks

 

[ban-all-sheds]

can anyone enlighten me as to how I can post the piccys in the Forum for general comment?

You need a website. You put the pic on it, and in your post here include the following:

[ img ]URL-OF-PICTURE[ /img ]

(but without the spaces inside the square brackets, obviously). Easiest way is to type or paste the URL, highlight it, and click the Img button.

There is an alternative - you can arrange to email the image to the admin(s) of the forum, and then they host it, but it's a bit drawn out. Check with your ISP - you may get a few MB of webspace with your account.

 

[breezer]

see here

 

[ban-all-sheds]

In the interests of keeping the forum looking nice and tidy, your signature must not contain any images, links or email addresses. These can be stored in your profile.
Any offending signatures will be edited.

 

[breezer]

perhaps i should have mentioned see 2nd post down (adding picture)

 

[ban-all-sheds]

That isn't what I meant - I was quoting the rule about not having images in signatures and wondering why you have an image in your signature.....

 

[breezer]

wondering why you have an image in your signature.....

Simple, i bent the rules.

Yes it is technicaly an image, but it appears as words, the words are not offensive, so it is allowed

 

[securespark]

Hi Dogz

Posted my e-mail address but has been taken off, so guess they don't like it.

 

[securespark]

As has my phone number........

Try a search for Secure Electrical Services in Bramhall Stockport!!

 

[dogzdinner]

Hi Securespark!
Thanx for that. Yes they removed MY emaill and phone number too. Read the T&C and they ain't allowed. Did a search online via Yell.com but only came up with S&B Electrical & Security Services but they are in Poynton, nr Stockport & not Bramhall. Wished I still lived up there - I'm in London but my family live in Denton, Audenshawe (nr Hyde) & Glossop.

Can you supply your full address if the one above isn't yours so then I can try to get your number via Dir Enq's.

The prob I have is a real so & so and would re-wire were it not for the fact that the place has a flat roof with no loft so would have to bring the ceiling down.

Cheers - Dogz

 

[dogzdinner]

to all you blokes that gve me advice on 2 way switching - many thanks and have a beer on me. Found out the problem - it was a double 2-way switching system in that it didn't just involve stair lights aaadn landing lights but an OUTSIDE light as well (which was kerry packered anyway!). Once this sorted all fell into place and works a treat now. Thanks toyou all again.

Dogz

and by landing lights I don't mean those at Heathrow just down the road from me!!!!!