Can I run a new switch from an intermediate

[8ballpoolplayer]

Hi Everyone,
I’ve got an unusual situation with a 3 way switching.
I need to add another switch. I will call the new switch 2a .. However, I can’t access the wiring to switches 1 and 3 (long story, but it’s impossible in this particular situation)
Does some kind soul who’s brainier than me, know of any way I can run the extra switch from switch 2 ( an intermediate switch) to 2a without having to connect between the other switches ?

Kind regards

 

[ChipFanDave]

You just need to run in two T+E cables to the new intermediate switch.

 

[8ballpoolplayer]

You just need to run in two T+E cables to the new intermediate switch.

Thanks very much David,
The problem is actually slightly more tricky so am hoping I pick your brains a little harder ?!
Is there any way the new switch can be a standard 2way switch .. I need to run a separate 2 way light from the new switch, but can’t find anyone who can supply a 2gang switch (with a 2way and an intermediate in one switch unit) ?

 

[mattg4321]

Most brands supply such a thing in grid form. Scolmore - Click do this as standard though. You just buy a 2 gang switch and an intermediate module.

 

[FatAlan]

You could use a two gang switch with grid modules. You would need a permanent live feeding the additional light though as you’d only have switched lives at the new switch.

 

[8ballpoolplayer]

Most brands supply such a thing in grid form. Scolmore - Click do this as standard though. You just buy a 2 gang switch and an intermediate module.

Thanks .. ?

 

[8ballpoolplayer]

You could use a two gang switch with grid modules. You would need a permanent live feeding the additional light though as you’d only have switched lives at the new switch.

Thanks ?

 

[Lucien Nunes]

There are also 2-gang intermediate switches that are not part of a grid system. Use one gang for the extra intermediate switch on your existing light, and the other gang for the new 2-way. To use an intermediate as a 2-way; use one pair of L1 / L2 terminals as such, and either terminal of the other pair as common.

That is, if we have understood correctly exactly what you want to do: A new switch position providing a 4th control point for the existing 3-way, plus one end of a new 2-way. As per @FatAlan, unless you are very lucky and additional cables pass through the existing intermediate box, there won't be either permanent line or neutral, or both, so some other feed will need to be picked up if the new 2-way requires one.

 

[brianmoooore]

There are also 'unofficial' grid switches that can be used for the job, although I doubt the manufactures would publicly approve.
Some makes of switches have the individual switches attached to the plate by screws. By buying a 2G2W and an intermediate of one of these, and spending a few minutes re configurating, you end up with a 1G2W switch and a 2G switch consisting of a 2W alongside n intermediate.

 

[andyb]

There are also 2-gang intermediate switches that are not part of a grid system. Use one gang for the extra intermediate switch on your existing light, and the other gang for the new 2-way. To use an intermediate as a 2-way; use one pair of L1 / L2 terminals as such, and either terminal of the other pair as common.

That is, if we have understood correctly exactly what you want to do: A new switch position providing a 4th control point for the existing 3-way, plus one end of a new 2-way. As per @FatAlan, unless you are very lucky and additional cables pass through the existing intermediate box, there won't be either permanent line or neutral, or both, so some other feed will need to be picked up if the new 2-way requires one.

There's an even chance of finding a permenmant live at the intermediate, if it's been wired in a traditional 3 plate system, But as you say, a very small chance of finding a neutral.

 

[FatAlan]

You just need to run in two T+E cables to the new intermediate switch.

Would that actually be 2x 3 core and earth cables?

 

[brianmoooore]

Would that actually be 2x 3 core and earth cables?

Not for the intermediate switch - four connections, so 2 X T&E. If by any chance one of the incoming wires is a permanent live, and there's a neutral present as well, one T&E and one 3&E would be sufficient to provide a supply for a lamp connected to the secon switch at the new position.