Question Confused about wifi enabled smart light switches

techno79

Active Member
I'm having my house renovated and I just don't have the budget to stretch to smart light switches. Thus the entire house will be using non-smart light switches. Most of the house will have LED dimmable spotlights. The light switches will be dimmable. There are a few spotlights that will be controllable via 2 ways switches (one side will be a dimmable switch with push on/off and the other side will be a standard on/off switch).

My questions are:
  1. Are wifi smart light switches interchangeable with dumb light switches? (i.e. all the wiring for a standard switch is all that is required for the smart switch)?
  2. If the above is no, what does the smart switch need that the dumb switch doesn't? And is it possible to add that from now while the house is in a state where I can add wiring?
I want to make sure I'm future proof for installing the smart switches when budget allows.

Thoughts/suggestions please?
 

mushii

Distinguished Member
Just make sure your electrician wires your switch’s with Neutrals and you will be good to go. Oh and make sure he uses deeper back boxes, I use 50mm back boxes as they provide plenty of room. They take a bit of chasing but you can use one of these if you have a lot of them to sink

Amazon product
or from here

Electrical Box Sinker Tri-Cut Set

If you are working on an old property with solid brick walls, this will save you 'days' of work sinking deep back boxes. You will need a decent SDS drill with hammer action.
 
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sbriggs

Active Member
Your budget for smart lights can be as low as £10 per lighting circuit or £20 per dimmable circuit

easier to do now
 

techno79

Active Member
Just make sure your electrician wires your switch’s with Neutrals and you will be good to go. Oh and make sure he uses deeper back boxes, I use 50mm back boxes as they provide plenty of room. They take a bit of chasing but you can use one of these if you have a lot of them to sink

Amazon product
or from here

Electrical Box Sinker Tri-Cut Set

If you are working on an old property with solid brick walls, this will save you 'days' of work sinking deep back boxes. You will need a decent SDS drill with hammer action.
Hi Mushii. Thank you, I'll have to speak to my builder/electrician to see if its not too late to get neutral wires into the light switches. Is it a big chore to get neutral wires into a switch which doesn't have it? Where does the neutral wire come from?

I did some reading and I can see there are some smart switch solutions that work without neutral wires. Are these comparable to the smart switches that need neutral? What are the differences. If I can get the builder to change things then that would be great but if that's not possible then is it a reasonable plan B to limit myself on the smart switches that do not need neutrals?

Many thanks in advance
 

mushii

Distinguished Member
'Old School' wiring for lighting rings only drops a 'switched live / line' T&E to the switch and the wiring for the light is done at the ceiling rose. A more modern approach is to drop 2 pairs of T&E to the switch, one T&E goes directly to the bulb and the other T&E pair is a Line and Neutral. This allows far more flexibility in switching.

It uses a little more cable, the 'old school' lighting ring stems from the end of WW2 when raw materials, especially copper was in short supply and was designed to use the minimum amount of cable create a lighting circuit. Although still effective it is a 70 year old design and things have moved on quite considerably since then. Many electricians recognise this and will wire with Neutral at switch these days, but some 'older electricians' or budget conscious electricians may still use the old 'switched live / line' approach.

If you want to provide for current and future smart lighting technology you really need to have a Neutral at the switch. There are smart lighting modules that can work without a Neutral, but these are 'Vampire' devices that continually draw a small amount of current and do not completely turn a light off, they just dim it to a level where it isn't producing any visible light. I would try and avoid doing this if possible.
 

techno79

Active Member
'Old School' wiring for lighting rings only drops a 'switched live / line' T&E to the switch and the wiring for the light is done at the ceiling rose. A more modern approach is to drop 2 pairs of T&E to the switch, one T&E goes directly to the bulb and the other T&E pair is a Line and Neutral. This allows far more flexibility in switching.

It uses a little more cable, the 'old school' lighting ring stems from the end of WW2 when raw materials, especially copper was in short supply and was designed to use the minimum amount of cable create a lighting circuit. Although still effective it is a 70 year old design and things have moved on quite considerably since then. Many electricians recognise this and will wire with Neutral at switch these days, but some 'older electricians' or budget conscious electricians may still use the old 'switched live / line' approach.

If you want to provide for current and future smart lighting technology you really need to have a Neutral at the switch. There are smart lighting modules that can work without a Neutral, but these are 'Vampire' devices that continually draw a small amount of current and do not completely turn a light off, they just dim it to a level where it isn't producing any visible light. I would try and avoid doing this if possible.
@mushii thank you again for your detailed response. I must confess that I never really knew how the wiring for light switches work. In fact, I'm still not sure I understand it fully even now. Terms like T&E are completely new but I've googled it. I think I need to watch some youtube videos that go into the basics of explaining the wiring of light both with and without neutral.

I totally understand your last paragraph and the ideal solution is to have a neutral at the light switches. I'll speak to the builder/electrician to wire in a neutral at the switches but what happens to this wire if it is not used for the dumb switches I will be using initially? Is the wire left unconnected (in a safe way) within the housing?

The work around for a non-neutral smart switch with its vampire drain doesn't sound good. Sounds like that the combined extra power draw would add up to something substantial over many years. Planning to stay in this house for a very long time (at least a decade or two). Thus sounds like even if there's an increased cost at this stage to add the neutral wires, I should ensure that this is wired in.
 

mushii

Distinguished Member
Sorry - T&E - Twin and Earth - standard double insulated cable used in most household wiring. I think when we had our kitchen extension wired - 9 Lighting circuits, it added less than £50 extra in materials to add the extra Neutrals at the switch. In the grand scheme of things it was negligible.

Quite honestly it should not be much in the way of extra work for your electrician.

1600164813733.png

This is Switched Live / Line configuration


1600164882136.png

This is Neutral at switch (note the connector block would be in the switch back box)
 

sbriggs

Active Member
If you do go Fibaro or Shelly I have wiring diagrams I can let you have whether it be with or without neutral and both single and two way switching .

I also recommend using 3 way centre off retractive switches as then you can also dim at the switch as well as via app and scenes

they are readily available from scolmore and varilight in various finishes
 

techno79

Active Member
If you do go Fibaro or Shelly I have wiring diagrams I can let you have whether it be with or without neutral and both single and two way switching .

I also recommend using 3 way centre off retractive switches as then you can also dim at the switch as well as via app and scenes

they are readily available from scolmore and varilight in various finishes
Thank you, I will definitely look at Fibaro and Shelly solutions when I come to upgrade my switches but that will be some future point down the road. Right now, I just need to make sure my wiring is future proof.
 

techno79

Active Member
Sorry - T&E - Twin and Earth - standard double insulated cable used in most household wiring. I think when we had our kitchen extension wired - 9 Lighting circuits, it added less than £50 extra in materials to add the extra Neutrals at the switch. In the grand scheme of things it was negligible.

Quite honestly it should not be much in the way of extra work for your electrician.

View attachment 1365980
This is Switched Live / Line configuration


View attachment 1365981
This is Neutral at switch (note the connector block would be in the switch back box)
Sorry, I'm still a little confused. Seems like the old style wiring uses a 2-core+earth at the switch where as the modern wiring has two 2-core+earth at the switch. Given that a 2-core+earth has live, neutral and earth, then isn't it the case that both the old and new solutions have neutral wires at the switch. And thus if I ask my electrician to ensure there is a neutral wire at the switch, then he will say yes he has already done so even though he is using the old style wiring.

What is the exact unambiguous description that I need to ask my electrician to ensure that the light switch is done in the modern way (i.e. with two 2-core+earth at the switch)?
 

mushii

Distinguished Member
In the Switched Line only 1 twin and earth comes into the switch and you are not providing a Neutral as the Blue (Neutral wire) is sleeved with a Brown ring or sleeve indicating that it is now a Line wire. Whereas in the second arrangement 2 twin and earth wires come into the switch and the Blue wires are Neutral this time
 
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mushii

Distinguished Member
What is the exact unambiguous description that I need to ask my electrician to ensure that the light switch is done in the modern way (i.e. with two 2-core+earth at the switch)?
You want a Neutral at the switch is what you need to ask your electrician. NOT a switched line.
 

techno79

Active Member
And just for information, how much vampire drain is there with using a smart switch on an old style wiring? If the vampire drain is on a switch which is connected to multiple spotlights (e.g. 6 or 10), then wouldn't this add up? i.e. vampire drain would be for each bulb that's used?

I'm planning to have LED dimmable spotlights but still, a constant and forever drain when the lights are off seems like it will stack up.
 

techno79

Active Member
You want a Neutral at the switch is what you need to ask your electrician. NOT a switched line.
And just to be totally clear, the classic old fashioned on/off light switch and the same old classic dimmer switch with a rotating knob can still be hooked up to a light switch with the modern wiring of having neutral there?
 

sbriggs

Active Member
Rotary dimmers can have issues with LED bulbs , such as a small dimming range so if you are thinking upgrading to smart modules later then probably not worth the extra cost of rotary dimmers (which cant be used with the smart modules)
 

techno79

Active Member
Rotary dimmers can have issues with LED bulbs , such as a small dimming range so if you are thinking upgrading to smart modules later then probably not worth the extra cost of rotary dimmers (which cant be used with the smart modules)
The LED spotlights and their mounting I'll be getting will the the type that are suitable for dimming. I know there are some cheaper LED spotlights that are not completely compatible. The basic switches and dimmers are included by my builder. I would love to get smart switches from now but due to budget constraints, I had to make some compromises to the project. So, things that can easily be upgraded at a later stage have been postponed (such as smart switches).

The purpose of the thread was to make sure there wasn't anything that would cause problems with that future proofing. Everyone has been really fantastic on this thread and very helpful.

I'm going to make sure all switches have neutral wires as then at least the wiring is ready for when I do come to upgrade the switches to the smart variety.
 

sbriggs

Active Member
Worth getting a couple so you can have a play before you invest more.

LED spotlights can be dimmable but still temperamental with rotary switches
 

techno79

Active Member
Worth getting a couple so you can have a play before you invest more.

LED spotlights can be dimmable but still temperamental with rotary switches
Yep, definitely worth buying one spotlight to test first before buying the rest. Are there any other non-smart dimmable switches that might give better compatibility? I need to keep initial costs low, especially when all the switches will be swapped out within the next year or so.

In the absolute worst case scenario, I'm even happy using normal on/off switches with my dimmable spots because I know I'll get my dimmable functionality once the switches are upgraded to smart variety.
 

sbriggs

Active Member
Yep, definitely worth buying one spotlight to test first before buying the rest. Are there any other non-smart dimmable switches that might give better compatibility? I need to keep initial costs low, especially when all the switches will be swapped out within the next year or so.
Probably but at £20 adding the smart dimmer module will probably be cheaper and wont then need swapping out later.
 

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