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Changing a 3 gang light switch with 2 2-way switches to smart switches - wiring Help!

Postby Bos. » Wed May 06, 2020 9:00 am

Hi all,

I recently moved into a place and I'm starting to make some home improvements.

I have a 3 gang light switch in my hall way which needs replacing and would like to install a smart switch.

This 3 gang appears to have 2 2-way circuits, 1 for the ground floor (additional 1 gang switch on another wall) and 1 i believe for the landing light (additional 1 gang switch upstairs), and a final simple switch for an exterior light.
I've mocked up a diagram of how the current switch is wired up to give you an idea:
Light switch diagram.jpg


Switch 1 is for the exterior
Switch 2 is ground floor
Switch 3 I believe is for the landing light, however it has not worked since moving in (rocker broken)

I am thinking of swapping this for this smart switch:
https://www.amazon.co.uk/Touch-Light-Sw ... r=8-5&th=1

I understand I will essentially need to replace all switches with these smart switches so they can communicate with each other. I have changed simple light switches before but I just wanted a bit of advice before I dive in and commit to purchase and to the task!

smart switch back.jpg

It appears on the smart switch that L is live and L1, L2, L3 should go to each light, however i'm not entirely sure how to fit this based on the current set up.

I had noticed a thread on here where someone was looking for advice for a similar switch but slightly less complicated.

Any help on this would be very much appreciated!

Thanks!

Craig
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Postby Mr White » Wed May 06, 2020 5:38 pm

I thought I should ask, 3 times you have said "smart switch" do you realise that it is just an on/off switch that you gently touch to operate, it is not "smart" at all.

By "smart" I am meaning being able to be controlled from your phone or "an amazon echo or google home mini"

It also requires a 35mm back box which most light switches do not have.

Although it is 2-way it will not work as 2 way unless it's counterpart 2 way switch is changed. It can not work with your existing switches,

You can buy a 3 way switch to replace yours for less than £3.00

On the assumption you are aware of all of the above, your statement
Bos wrote:It appears on the smart switch that L is live and L1, L2, L3 should go to each light.
is correct.

The problem is then
Bos wrote: however i'm not entirely sure how to fit this based on the current set up
It depends how who ever wired it chose what colour does what, as with 2 way switching there is no "standard colour code" so it would need further investigation as to what does what to connect it so it will work.
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Postby Bos. » Wed May 06, 2020 5:52 pm

Hi Mr White,

Thanks for your response. Indeed, by “smart” it is meant that it can communicate with an app and/or Alexa via the wifi - apologies if I repeated the word too many times.

I am aware that I will need to also change the counterpart switch, which is fine. To be honest I’d like to change all the switches anyway, they are all looking a bit aged.

You are right, i could indeed just replace like for like for a very small cost. Although, the idea of being able to control the switches remotely is very appealing as our place is split across 3 floors, and it’s a bit of a pain if you forget to turn the light switch off on the top floor!

I cant seem to find any examples online of someone fitting a switch similar to this so thought i’d give this place a go

Any help or comments always welcome!
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Postby Mr White » Wed May 06, 2020 9:39 pm

Bos wrote: the idea of being able to control the switches remotely is very appealing as our place is split across 3 floors, and it’s a bit of a pain if you forget to turn the light switch off on the top floor


Then that switch is NOT for you, as I said previously that is NOT a smart switch.

If you want to be able to control your lights from an App I would suggest you look at "smart lamps" since as you pointed out smart switches require a neutral which most existing light switch wiring does not have.
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Postby ericmark » Thu May 07, 2020 3:53 am

Two of the switches you show are two way, smart switches do not work the same as the change over switches, they have a S terminal which should not be connected to mains, you have a master and slave switch.

There is a problem also with two and three gang, I don't even know if you can get three gang without neutral, and the two gang the master are on one switch and slave on the other, you can't get a mixture of master and slave on one switch, and your diagram seems to show that is what is required.

So it would seem you would need to lose the two way switching on at least one circuit, and the switches which do not require a neutral are not cheap, I use Energenie MiHome which need a hub, so likely little change from £100.

I use the remote controls a lot, but rare to use phone or PC, if you lose one two way system, I think there are other systems that don't need a neutral but I have only used the one.

I use the smart switch instead wiring up two way switching, for me the hub had already been bought to work the central heating so I only had cost of switch, then HomeBase stopped stocking the Energenie range and sold off their stock, rather cheap so I bought the rest cheap.

However it has caused problems, the BA22d lamps have worked A1, but the G9 lamps were a nightmare, needing load capacitors and ending up with one quartz lamp as only way to stop the flicker, and I have needed to add socket spacers to some as boxes not deep enough.

I had one rouge switch which seemed to have compatibility problems with one of the sockets and it would switch on and off with a mind of its own.

As to the Nest mini they are like mischievous boys, and have removed them from controlling lights, sockets, and TRV heads, as you would say hay google turn off music, and it would reply turning off 5 switches and all the lights would go out, but ask it to switch them back on and it says don't know how to do that yet.

I would suggest you wait until after lock down, I ended up using three electrical whole sale outlets to get the bits I needed, no one outlet had them all, this is not the time to be hunting for spacers or load capacitors, OK I am an electrician and even I had problems, I really pity the DIY man trying to fit these devices, it is not as easy as it seems.
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