Interesting three way conversion to two way and swap for time lag.

[The Ghost]

If your bored or like a challenge I thought (maybe wrongly) this might be interesting to trainees and maybe others. As the title convert three way switching to two way (Sw 2 + 3) danlers time lag (Master and slave) using switch 2 and 3. Assume you cannot find the junction box. Can it be done? Note we have L in at switch 1, no accessible switch return. I included a couple of photos to give the ---- drawing some context. The switch return (green) is pure conjecture on my part, but it must be something along those lines. There is no switch return wire at any switch.

 

[The Ghost]

Oh sorry the first picture was meant to be intermediate switch like this:

 

[buzzlightyear]

the plan you are using will not work ,

 

[The Ghost]

will not work

You've given the game away. This is the existing wiring not the plan. The plan is what to do with it to get to Master and Slave on 1 and 2. I will tell you what I actually did before too long.

 

[buzzlightyear]

was that how it was wired ? and if saw you have two opposing current .switch 3 to switch 1.!

 

[telectrix]

question is... do to need to run the cable in mid-air over the neighbour's garden? if so to need a catenary wire as well as them strappers.

 

[Leesparkykent]

Looks like a standard 2-way to me. Feed in and feed out in the common of Sw1, strappers through intermediate switch and yellow from Sw3 is the SL to the light. If your getting rid of Sw1 you could connect the live through to sw2 and connect the SL and L through in parallel to switch 3. Or am I missing something?

 

[The Ghost]

Sorry did not label it but from the photos and diagram you should see the live comes into sw 1 common-to either L1 or L2 on red cables to the intermediate L1 and L2 (Sw 2) correspondingly (all belled out by the way) then from the intermediate top, to the three core R-Y-B two way switch (Sw 3) again belled out from intermediate L1 L2 top to L1 L2 on sw 3 hope that's clear. There is no switch return that I can make out. Or am I missing something?

 

[The Ghost]

Bear in mind the junction box is assumed as there is no other way the lights can switch on which they do by the way. I have had no sight of the junction box, could be in the wall joined to old MICC (quite common in this building) or JB in loft 20 foot up with a 2 foot by 2 foot hatch leading to a sargasso sea of cables dust an inch thick and billions of data cables just thrown over the loft and so on.

 

[Flanders]

Where is the light in your drawing , is the yellow cable the switch wire to the light via your hidden junction box?

 

[The Ghost]

was that how it was wired

The JB is just conjecture I could not bell out those wires conclusively. So no not necessarily.

 

[Leesparkykent]

Where is the light in your drawing , is the yellow cable the switch wire to the light via your hidden junction box?

That was my assumption.

 

[The Ghost]

Where is the light in your drawing

There are two lights on the stairs. If the yellow cable is the switch return where does the common go to at switch 1 if not the yellow cable at switch 3?

 

[Leesparkykent]

There are two lights on the stairs. If the yellow cable is the switch return where does the common go to at switch 1 if not the yellow cable at switch 3?

sw 1 common perm live, strippers through to int, other side of int to junction box, strappers connected to sw3 and Yellow from common sw 3 is SL to lights.

 

[The Ghost]

Feed in and feed out in the common

Eh? of switch 1 there is only 1 L feed into sw 1 there is no feed out and the rest of the cables look like an ordinary three way switching arrangement apart from on thing, there is no visible sw. return.

 

[Leesparkykent]

sw 1 common perm live, strippers through to int, other side of int to junction box, strapped connected to sw3 and Yellow from common sw 3 is SL to lights.

 

[The Ghost]

Yellow from common sw 3 is SL to lights.

Agreed, now you can't (for the sake of argument and practicalities) get to the junction box. So I want to convert this to two way master and slave time lag switch. So usually L and Sw return to master and use two of the strappers for the slave. But the L is at switch one which is being gotten rid of. The answer is a nothing to do with this problem I might add. It is just a mind bender for trainees really, and hopefully they might think it can't be done will have to do something else which I did.

 

[The Ghost]

@Leesparkykent you are missing the two wires in sw 1, look at the grid switch with a borrowed live from the adjacent grid switch you can see two wires in the common.

 

[buzzlightyear]

what a head scratcher, now let me think about it ,not the wiser .

 

[Leesparkykent]

Eh? of switch 1 there is only 1 L feed into sw 1 there is no feed out and the rest of the cables look like an ordinary three way switching arrangement apart from on thing, there is no visible sw. return.

looks like two reds in common to me.