Switched Wiring Question

[krg1605]

I have two new switches that are powering one light from opposite sides of a kitchen.

I have old wiring - red and black.

In the first switch, the live (red) coming in, I have into the common terminal at the top and the other red wire (which feeds the other switch) into the same terminal.
The black wire is in the two way terminal at the bottom.

In the other switch, I have the red live coming in from the other switch which again is in common.

The black is in the two way (same as the other) and the last red wire (which I assume continues the circuit) is in the one way terminal.

When I use the switches I find that the second switch works fine for switching the light on but the first one makes no difference, i.e. it does not work in either position.

So it appears that the first switch is giving power to the second one but does not seem to work in terms of switching the light on or off.

I assume I have the wiring in the wrong terminals to allow both switches to control the light but do not know how to do this.

Can someone help?

[bhg481]

To the best of my knowledge you need 3 wires between the switches for a two-way system to work properly, the third one is usually yellow.

[Electrochem]

https://www.lightwiring.co.uk/two-way-switching-3-wire-system-new-harmonised-cable-colours/

[krg1605]

Thanks bhg but I do know that this did work on the old light switches I used to use with the same wiring. The old switches were not standard so had no idea which terminal did what. I'm sure I'm not far off but one wire needs moving somewhere else I think....

[New Judge]

Whatever the switches and whatever the colours of the wires, you cannot get two way switching to work with only two wires between the switches. The best you can do is where both switches would have to be "on" to light the light, though turning either of them "off" would extinguish it. I have a simpler diagram than the one provide din electrochem's link. I'll dig it out.

[New Judge]

Here it is:

https://ibb.co/xhYWHgp

You can eliminate Junction Box 2 - that simply provides a convenient method of linking the two switches (which will usually be some way apart).

You will see that you will need, in switch one, five wires in total (ignoring earth) and three in switch two. I really don't know how your system is wired. I should check out where each of the wires goes to, especially the black ones. Bear in mind that if these form part of the switch wire they are not -ve and may be live.

[krg1605]

Thanks for the feedback so far guys - all useful!

I did follow the diagrams that Electrochem provided and actually got a combination that at least gives me light :)
However, I did find that this only happened when both switches were in a particular position. But it works!

I haven't had a chance to look at what New Judge has sent me yet but I think this may be the 'missing link' to give me the right combo that works correctly.

I must admit one thing I didn't say is that I do have an extra red wire in one of the switches that I've proved is not actually a permanent live. But I do know the circuit doesn't work without it so it's in 'one way' at the moment.

Anyway, when I have a bit more time I'll give it another go.

Keep you posted!

[krg1605]

Hi guys! Update....

NJ - have had a look at your new diagram and, although the colours aren't the same, I think I can see why my circuit still isn't working.

This elusive 'yellow wire' that bhg talks about is probably my extra red wire. This would make sense as the light doesn't work at all when this isn't connected.

So to recap -

I have a red live coming into one switch and a red going out as a common to the other switch.

So the common goes into the common terminal, the red goes into 'one way' and the black goes into 'two way'.

In the other switch at the other end of the room, I have the common from the other switch going into 'common' with the other red (output to light) going into 'one way' and again the black wire into 'two way'. This second switch has no power coming in yet but can do with bridging from another switch (it's a double switch). So is this wiring right? And if it needs a separate bridge to use a permanent live, which terminal should this be in?

Gonna have another play with it tomorrow anyway but any feedback would be helpful.....

Thanks guys!

[krg1605]

By the way, the original live feed, in switch one, is in the one way terminal.

[krg1605]

ok - sorted!

The one lesson I have learned probably more than most is that it helps to know what each wire does!

I found this on youtube which completed the picture that you guys were so kind to start for me.



I found that the first technique (in and out through common) worked straight away with the black wire going 1w / 2w and the red wire going 2w / 1w. The final red wire out supplied the light from common.

So thanks for all the help guys...I've learnt a lot!

[SparklyKid]

Thought I would jump in here. The bulb will have a negative connection. The live will go one of the 2 switches. A pair of wires goes between the 2 switches. A live out will then go the bulb.

In other words the live feed to the bulb has a choice of 2 tracks.

[SparklyKid]

In hindsight, leave the positive feed at the bulb and switch the negatives, doh.

[Ryzen]

If the red and black wires are part of a twin cable try this...put the single red into common at each switch ..then put the red from the twin in L1 and the black from the twin in L2 at each end...Dont forget safe isolation!!

[TonyV]

I sorted this problem by putting a "jumper" cable in one switch between live and neutral

[Ryzen]

Tony...putting a jumper cable between live and neutral wont solve anything...it will result in a loud bang ..and a red face:-)

[krg1605]

Thanks for all the feedback guys but this problem is sorted now.