Lighting puzzle

[endecotp]

Dear All,

Please treat this as a logic puzzle for your enjoyment, not a call for assistance!

Currently my living room lights are controlled by two switches in a conventional way as shown:

The wires are singles in conduit.

I'd like to add an additional light, separately switched. Clearly it's not difficult to have it controlled from a switch at the left side of the room:

Question: How can I also control it from the right end of the room? As shown above, there is currently a pair of unused yellow strappers running from one switch box to the other. Can I achieve two-way switching for the new light using these yellow wires?

Note I'm not interested in solutions involving smart switches, relays, or additional wires. The cable to the new light needs to come from the left switch box as shown. All that's allowed is changes in the two switch boxes.

I'll post my own thoughts tomorrow!

 

[sparkwright]

Firstly, how easy is it to get a third (yellow or otherwise) wire there?
EDIT. Forgot this is a puzzle, rather than an actual problem.
Let me think...

 

[mikehammer69]

Wrong..

 

[securespark]

You'd need a third wire.

Or a live feed on that side to piggy back off to the common.

 

[ericmark]

Note I'm not interested in solutions involving smart switches, relays, or additional wires.

So you don't want a solution then, so why post?
Uses additional wires, so not valid.
I had a problem with a dinning room, which after my wife's operation was to become her bedroom until she could climb the stairs again, the problem was how to mount a switch, remote etc. Where my wife could easily put her hands on it in the middle of the night.

The method selected was the Tapo button, and wall switch. This seemed an ideal method, the S200D has the frame, the S200B is a simple button, it lasted one night, then she moved to voice control, and the button has been reused as a doorbell push.

There are other methods, some electronic switches only need two wires, some use the kinetic idea, moving the switch generates the power, the Tapo uses batteries.

I still use some Energenie MiHome light switches, you can get a master and slave, but never seen the slave sold on its own.

Using DC and diodes, one can use a pair of wires, to light two bulbs independently although not together, but needs the diode, so not sure if it fits the requirements, suppose one has to define smart!

Lack of access into the ceiling space, means I can't run extra wires, and having lights run off 13 amp outlets, means switches spread around the room, pain in the neck before going to bed, turning off all the lights, so I have looked to the smart way to group lamps together.

So for me, they must say works with Google home, son uses Alexa, which does same thing. And hey google turn off lights will turn them all off, does not matter what make, or where they get power. And a darn sight cheaper to running new cables.

 

[SUNRAY]

My initial thought is additional wiring is required but the least I think I see is this with extras shown grey

Happy to see your thoughts

 

[mikehammer69]

hmm second thoughts rethinking it

Intermediate and 2-way to control new light

2 red strappers looped into intermediate on right from existing 2 way switch , 2 yellows out

Standard 2 way switch on left

I think that works

 

[AndyPRK]

My thought was the same as sunray. But I don’t know if we were allowed to add the additional wire between the light and left sw

 

[mikehammer69]

I'm reasonably confident my idea works

Intermediate fed from 2 existing strappers on right , standard 2-way on left

No feed or additional wiring needed

 

[EFLImpudence]

I'm reasonably confident my idea works

Intermediate fed from 2 existing strappers on right , standard 2-way on left

No feed or additional wiring needed

Please explain - diagram?. I am not sure if I understand the layout.

 

[pete01]

It's not possible

 

[mikehammer69]

Please explain - diagram?. I am not sure if I understand the layout.

You use the existing yellow strappers twice

They also feed the intermediate for light 2

 

[mikehammer69]

One of the intermediate feeds is always live

I think that works , it'd be the same as 2way > int >2way and there's no crossover, i think

 

[EFLImpudence]

Apart from that, are you forgetting that light 2 can only be wired from the left hand side?

 

[trojanhawrs]

Apart from that, are you forgetting that light 2 can only be wired from the left hand side?

View attachment 396466

It doesn't really matter as per the diagram which side the light's on. 2 cores between intermediate and light 1 switch 2, 2 cores between light 1 switch 2 and switch 1. What's more problematic, is the first switch in the line will swap states on both lights