Wiring a Lightswitch Toggle Single 2 Way type

[MikeDee]

ok guys, ill try to make this sound as easy as possible.....i have a single light fitting in Living Room ceiling operated by 2 seperate 1 gang fitments (1 gang 2 way units)....

Removed the 2 existing fittings.

They BOTH have 3 wires (Black, Blue and Yellow) coming from the wall fitting (fairly modern house). And there is existing earth connections (Yellow & Green) fixed to the casings (these are thicker sleeves). The 3 RBY wires were going into the old switches in the following order:- Red to L1, Blue to L2 and Yellow to C.

Replaced same with the new fittings. The new units had exactly the same markings (i.e. 'L1', 'L2' and 'L' (the 'L' marking is the yellow or grey according to fitting instructions)). All connections were good and tight.

I can get one of the new units to work but the other new one wont. I removed the new one that didnt work and replaced it with old switch unit. The old one wont work now either! This tells me im maybe doing something wrong with one of them? Ive replaced loads of theses switches in the past with no problems. Thought it would be a 10 min job as well !!
What im i doing wrong?
Cheers
Mike

 

[MikeDee]

But he has only mentioned one three core cable at each switch. This means either a hidden term box or the three cores both join at the pendant (cable saving method).

Mike, can u say what cables are at the light fitting?

i replaced the light fitting 3 weeks ago. Removed the old rose etc and replaced with new lights.
If i remember rightly, the new wires from the new light fitting were RYB. These were connected to the connector box on ceiling fitting (which was Black, Red/Brown & Yellow' n Green going into the connector box from inside the ceiling)
Bit late for removing it tonight, but what i can't understand is after i renewed the lights it worked well from both switches. Surely these new switches wouldn't have made the slightest bit difference as the wiring is/was the same (like for like)...

 

[Steve]

(the 'L' marking is the yellow or grey according to fitting instructions)).

THIS may be where you're going wrong. Is this how it was wired before? (C = L)

You shouldn't have used the instructions - simply re-locate the cables into the new switch the same as before.

Fortunately the cores you have are ALL live so if you like you can use the trial and error method - you wont blow any fuses etc.

 

[MikeDee]

(the 'L' marking is the yellow or grey according to fitting instructions)).

THIS may be where you're going wrong. Is this how it was wired before? (C = L)

You shouldn't have used the instructions - simply re-locate the cables into the new switch the same as before.

Fortunately the cores you have are ALL live so if you like you can use the trial and error method - you wont blow any fuses etc.

cheers for that Steve
i spoke to a former spark at my work and he told me the same today. I didnt take a note of the old wiring (should have as im colourblind!) but he said locate the red to "L" (or "C" as it was before), Yellow to L1 and Blue to L2. I think this will work. Leaving here shortly to go home and do it !
will let you know the outcome
thanks again
Mike

 

[MikeDee]

im gonna have to wait until Friday or Sat daytime now to do this due to limited light time (its mighty dark up here in Scotland!)
Will report back!
thanks to all who've helped

 

[Taylortwocities]

Oh why didnt I think of that?

It is more normal for the red to be on C and yello & blue on L1 and L2 at both ends.

Oh I did, several days ago.....

 

[MANDATE]

Mike! You might have a better understanding of two way switching if you realized there are two different methods.

The present method involves the supply 'live' and the return 'switched live' connected to the same switch on terminals L1 and L2.
The strapper comprises 3 core wires from Com L1 and L2 from SW1 to the same terminals on SW2.

The older method has the 'supply live' connected to 'com' on SW1 and the return 'switched live' connected to 'com' on SW2.
The strapper comprising 2 core wires from L1 and L2 from SW1 to the same terminalsd on SW2.

No of wires in the switches are either 5+3 or 3+3.
From what I've read yours is the older method. You just have to indentify which is the supply live in which switch. The remaining 2 must be the strapper.

 

[MikeDee]

(the 'L' marking is the yellow or grey according to fitting instructions)).

THIS may be where you're going wrong. Is this how it was wired before? (C = L)

You shouldn't have used the instructions - simply re-locate the cables into the new switch the same as before.

Fortunately the cores you have are ALL live so if you like you can use the trial and error method - you wont blow any fuses etc.

you were right!
instructions were wrong.
All fine and dandy now, thanks!