Cannot get replacement light switch to work like old one...

[Hnev]

I've replaced all the light switches in 1960s house with modern on/off designs which use a simplified small brown connector block labelled L1, COM and L2. All are working perfectly apart from the hallway, which has a standard on/off switch at one end and a double on/off switch by the front door. The latter switch controls the outside porch light as well as the hall lights. I have wired this switch precisely as it has always been, following the labels on the old plastic moulding - across top row - A COM; B 1way; B 2way, and across the bottom row - A 1way; A 2way; B COM. The coloured wiring, in the same order was as follows: (top row) Red; (linked to) Red; Blue. And (bottom row) single Red, N/C, Yellow.
Transferring this wiring arrangement to the new style switch which contains two separate connector blocks was straightforward - the single outside light uses the single Red to L1, the linked Red to COM and N/C at L2. The two way circuit uses the linked Red to L1, the Yellow to COM and the Blue to L2. This corresponds exactly, I think, with all wires located in their modern equivalent terminals.

The problem arises at the other end of the hallway. Removing the old switch last autumn before the snow forced stoppage of work, I cannot remember how it was wired up, because there are too many wires for the new 3 terminal switch block. A double-twisted Red, a Blue, a single Red and a Yellow. I have tried a few variations which result either in the hall lights not working at all or else the lights in the hall working but only when the hall-end double switch is 'On'. At this setting the single switch will switch the hall lights on and off as 'normal'. However, when the far-end switch is 'Off', the single switch has no effect at all.
There are more wires than there are terminals - at the moment I have wired the single Red to L1, the Yellow to COM, the Blue to L2 and the two linked (twisted together) reds N/C. I have not confused the single red and the linked reds - they have been twisted together for a long time and must have been used on the old switch. I have tried the twisted reds in L2 and the Blue N/C, but the result is the same.

I would be extremely grateful if one of your experts could please diagnose the problem and crack the wiring code for the single switch, so that normal operation could be resumed.

Thank you in advance

 

[telectrix]

virtually impossible to diagnose and correct without being there with test gear. if you post your location, i'm sure one of us is close enough to you to come and sort it for a reasonable fee.

 

[WDMDL]

Safety first... Are these new switches metal?

If so, have you got earth wires going to your back boxes and earthed the new faceplate?

Ok... I assume you have no test equipment.

The two way switch is what causes a lot of people problems.
Nowadays, evolution of best practice and awareness of the dangers of borrowed neutrals means the wiring is more logical.

But... what you have here is a bit of a patch-up, the old way of doing things.

Is there more than one light in the hall?
And does the porch light work whether or not the hall light works?

If this is the case, then it's looking like the this:
From the RYB:
R=L1
Y=COM
B=L2

The twisted reds in L2 with the blue.

Simon.

 

[WDMDL]

The preferred method of doing the 2-way switch is to have a have a standard Line and Switched Line on a T&E to one switch (using L1 and L2)
Then connect the two switches together with a 3&E: L1 to L1, L2 to L2, COM to COM.

You have the 3&E, it's just a matter of working out which is the Line (Looks like the linked red in the 2-gang switch)
Which just leaves something to be the Switched Line... (Looks like the twisted reds, at the other end of the circuit).

Simon.

 

[Hnev]

Double thanks Simon - plastic face plates so no worries there.
Yes there are four light fittings in the hall, and the porch light works regardless of hall light setting.
'A bit of a patch-up' would make sense as the four light fittings were a 'retro-fit' as I understand it.

Your solution would explain why all the wires showed signs of having been screwed into terminals, but the old switch would have had only three terminals for all these wires.

So, thanks for your solution - the blue and the twisted reds all go into L2, with Y=COM and single red=L1

If I could post double thanks I would!

Sincerely, Hnev

 

[Patta]

Get a qualified electrician in. Theres plenty of them on the dole