Electrical advice - how ‘backyard’ is my solution?

[Luckosaurous]

I’m in the process of making my home “smart”, I want the side lights in the kitchen to come on when a presence sensor detects someone in the room. I want the light switch on the wall to work like normal, but I also want the option to control the lights with my voice/phone irrelevant of what position the wall switch is in.

The problem is that most smart relay switches require a neutral wire, which I don’t have access to.

The light switch is on a solid block wall and the back box is only about 20-30mm deep, almost all of the space is taken up with the switch it’s self. I know Sonoff make a no-neutral smart relay, but there isn’t enough room in the back box for that and I don’t want to/wont be able to get mrs Luckosaurous to agree to, chiseling out the blockwork to make room for a deeper back box to accommodate that smart relay, so as I see it, that is out of the equation.

There is a switched live feed coming out of the wall into a junction box above the wall cabinets which would be no use to the sonoff relay as that needs to bypass the switch and so adding it to the circuit here would place it in the circuit after the switch, which would mean the wall switch would kill the power to it, so then the wall switch is off the voice/phone control wouldn’t work. They need a permanent live feed.

So my proposal is to take a 2 core and earth to take a permanent live feed from the fridge freezer socket and run that up to a junction box ontop of the kitchen cabinets which can house a smart relay, along with the switch live cables and the lighting circuit.

This option is the path of least resistance, it can all be done discreetly so there are no visible cables. But the drawback is that it then means that those lights are now fed off the kitchen appliance circuit rather than the ground floor lighting circuit.

I figure whilst I live here I can make any spark who may need to work on the house know about this ‘quirk’, and when I leave I can remove it and reconnect the lighting circuit to the switch as I will want to take all smart-home tech with me. So in my head it all seems relatively sound if slightly junky.

And so I turn over to you wise sages; am I missing anything important that I don’t know about that makes this dangerous, should I add a fuse between the appliance circuit and the lighting one in case the current becomes too much for lights to handle? (All cables i add will be outside of walls but behind the kitchen wall cabinets) or are there any more elegant solutions that I may be missing?

Edit: I should add, we have posh light switches, so swapping the switch for a smart light light switch isn’t an option.

 

[Spectric]

So my proposal is to take a 2 core and earth to take a permanent live feed from the fridge freezer socket and run that up to a junction box ontop of the kitchen cabinets which can house a smart relay, along with the switch live cables and the lighting circuit.

What is proposed is dangerous and you cannot just take a cable from a power circuit to supply a lighting circuit as the lighting cables cannot take the fault current of the power circuit. Reading your post it is evident that you are not electrically qualified and therefore should not be trying to alter the wiring in your house because apart from the fact you will not have the correct test and measurement gear to verify your work is safe it could pose a hazard to the occupants so it would be in your interest to get an electrician involved, the thing to remember with electricity is that just because it works does not mean it is safe.

 

[Luckosaurous]

What is proposed is dangerous and you cannot just take a cable from a power circuit to supply a lighting circuit as the lighting cables cannot take the fault current of the power circuit. Reading your post it is evident that you are not electrically qualified and therefore should not be trying to alter the wiring in your house because apart from the fact you will not have the correct test and measurement gear to verify your work is safe it could pose a hazard to the occupants so it would be in your interest to get an electrician involved, the thing to remember with electricity is that just because it works does not mean it is safe.

Absolutely correct, I’m not, and that’s why I’m asking for advice before I potentially do something dangerous.

What would you suggest given the situation I’ve described?

I’m assuming the ring main for the lighting circuit is in a junction box somewhere in the ceiling so I have no way of accessing it without making a lot of mess.

Are my only options to make the back box deep enough to use the sonoff, make the mess I don’t want to, or not install a relay? Or are there any other solutions you can suggest?

 

[LancsRick]

From what you've described I'd without doubt just make the back box deeper. It's an extremely easy job makes minimal mess an can be completed in 20minutes by a novice.

As always ensure you've killed the breaker for that circuit before messing with it.

 

[Luckosaurous]

From what you've described I'd without doubt just make the back box deeper. It's an extremely easy job makes minimal mess an can be completed in 20minutes by a novice.

As always ensure you've killed the breaker for that circuit before messing with it.

Come on now, surely I haven’t come across as that much of a novice? You’ll be telling me that I shouldn’t lick the live wire next

Fair play though I was expecting to be told the appliance circuit would be to high current, but I was hoping someone would tell me of an easy way to step it down, or that the lights would be the weak point on the circuit and act like a fuse but that the likely wouldn’t be overloaded anyway.

The reason I didn’t want that solution is that it’s very noisy and messy, and the Mrs isn’t keen with a new born in the house

 

[Spectric]

A lighting circuit is not a ring, it leaves the protective device in the board and loops in and out of the ceiling roses and stops at the last one on that circuit. The drops to the switches pick up live and the return takes it to the two way block the pendant is wired to with the other side connected to the neutral.

When I last wired any domestic I tried to use deeper 44mm backboxes and provide a neutral just so it was future proof for smart switches but I do not think this has become to popular.

As to your current issue, the best and safest way forward is to chase out and fit a deeper box, this is not as bad as you think unless the wall is concrete blocks, hopefully they will be celcon or such and keeping a hoover with you you can litterally scrape them deeper with an old wood chisel.

https://www.ener-j.co.uk/products/v...-touch-switch--1-gang-no-neutral-needed/99337

 

[Sideways]

@Luckosaurous
I was more inclined than @Spectric to start with the benefit of the doubt, but your reply makes it worse !
Just get a sparky in.

 

[Luckosaurous]

A lighting circuit is not a ring, it leaves the protective device in the board and loops in and out of the ceiling roses and stops at the last one on that circuit. The drops to the switches pick up live and the return takes it to the two way block the pendant is wired to with the other side connected to the neutral.

When I last wired any domestic I tried to use deeper 44mm backboxes and provide a neutral just so it was future proof for smart switches but I do not think this has become to popular.

As to your current issue, the best and safest way forward is to chase out and fit a deeper box, this is not as bad as you think unless the wall is concrete blocks, hopefully they will be celcon or such and keeping a hoover with you you can litterally scrape them deeper with an old wood chisel.

https://www.ener-j.co.uk/products/v...-touch-switch--1-gang-no-neutral-needed/99337

Yeah with the other lights I’ve fitted a Shelly 1pm mini in the ceiling roses, but with this particular circuit that junction must be somewhere hidden in the ceiling, this one only illuminates the under cabinet and plinth lights. I only have a switched live coming out of the wall and into a junction box that splits it to the cabinets on the other side of the room a the lights in the plinth.

The wall is breeze block so I can make it deeper, but the easiest route I saw for that would be to drill a series of holes and use a masonry chisel to remove material between them, which is very noisy and reasonably messy. Though I’m open to other suggestions if anyone knows a cleaner or easier way?

 

[Bingy man]

100% get a qualified professional electrician in and be safe, once it’s done correctly and safely you can control your lights etc without having to alter any hard wiring. Do it yourself and as @Spectric says you can’t even test it to confirm it’s safe . Burn your house down and you have no insurance. It’s just not worth it .. I can control most of my lights with motion sensors and smart bulbs and plugs and of course my heating all from the app on my phone . I c a n create recipes so as one light is activated the one in the next room come on and the room I’ve left is turned off , it’s compatible with Alexa and the only hard wiring was the receiver and at the time I installed it I was qualified to install it - it’s called hive -other makes are available but a lot safer than altering the existing wiring.

 

[Luckosaurous]

100% get a qualified professional electrician in and be safe, once it’s done correctly and safely you can control your lights etc without having to alter any hard wiring. Do it yourself and as @Spectric says you can’t even test it to confirm it’s safe . Burn your house down and you have no insurance. It’s just not worth it .. I can control most of my lights with motion sensors and smart bulbs and plugs and of course my heating all from the app on my phone . I c a n create recipes so as one light is activated the one in the next room come on and the room I’ve left is turned off , it’s compatible with Alexa and the only hard wiring was the receiver and at the time I installed it I was qualified to install it - it’s called hive -other makes are available but a lot safer than altering the existing wiring.

I’ve already converted the existing thermostat to a nest one myself. I’ve set up most of the other equipment myself and its is all tested for continuity and safe to my knowledge.

If I’m honest, as the thread tile suggested, I knew this wasn’t really a good or safe solution, I used it as a start to the conversation hoping someone would offer an alternative to the obvious which is just to either a) find the junction box in the ceiling and wire in a Shelly 1pm mini into there*, or b) make the back box deeper.

I was hoping for suggestions rather than the usual “just pay a spark”.

*though think about it I’m not sure that is safe as if it were ever to fail it would leave the lights perm live unless the circuit was broken at the consumer unit

 

[Matt_0222]

Philips Hue do these for the back boxes:

Philips Hue Smart Wall Switch Module Twin Pack. Works with Alexa, Google Assistant and Apple Homekit, Black
https://amzn.eu/d/aIBL1LM

If they’d fit.

Another option would be to leave the light switch turned on, replace e the bulbs with Philips Hue and then cover the light switch with a Philips Hue independent wireless switch:

SAMOTECH Hue Switch Cover V2 (Single Cover SM200 V2)
https://amzn.eu/d/8aIPBsQ

Or

IYOKI® Hue Switch Cover for Philips Hue Smart Button, Hue Button Light Switch Plate Adapter, 1-Gang (1-Pack)
Amazon.co.uk

The Hue lights and cover plate is probably the only option that requires zero wiring depending on what bulbs you have and can replace.

Hue also do the movement detector.

 

[Chief Sawdust Maker]

At times this forum throws up threads that have to be read to be believed, statements like

'all tested for continuity'
'safe to my knowledge'
'permanent live feed from fridge freezer socket'
'know about this quirk'
'So in my head it all seems relatively sound if slightly junky.'
'I should add, we have posh light switches, so swapping the switch for a smart light light switch isn’t an option.'

Please please please do the following
Get a qualified accredited electrician in to do the job and importantly check and test the other items you have installed.
Don't undertake any more work on the fixed wiring in your house

You are potentially putting yourself, your family, your property and any tradesman attending your property at risk.
You are in danger of voiding your house insurance,
You are potentially breaching the conditions of your mortgage company (if you have a mortgage)

Its about time the government brought in further legislation with regards electrical work.

There is a place for DIY but certainly not with regards to electrical works.

 

[Luckosaurous]

At times this forum throws up threads that have to be read to be believed, statements like

'all tested for continuity'
'safe to my knowledge'
'permanent live feed from fridge freezer socket'
'know about this quirk'
'So in my head it all seems relatively sound if slightly junky.'
'I should add, we have posh light switches, so swapping the switch for a smart light light switch isn’t an option.'

Please please please do the following
Get a qualified accredited electrician in to do the job and importantly check and test the other items you have installed.
Don't undertake any more work on the fixed wiring in your house

You are potentially putting yourself, your family, your property and any tradesman attending your property at risk.
You are in danger of voiding your house insurance,
You are potentially breaching the conditions of your mortgage company (if you have a mortgage)

Its about time the government brought in further legislation with regards electrical work.

There is a place for DIY but certainly not with regards to electrical works.

Any work I’ve done on the house so far has been tested and signed off by a qualified electrician.

I came here looking for guidance and information to make sure I didn’t do something unsafe. Why not educate me on why the proposal isn’t safe, and what I should be doing that you think I’m not, instead of just condescending me?

Okay taking. 13A circuit into the lights is a terrible idea, but I was hoping someone would point me in the direction of a
device that could step that current down to make it safe, or better yet a smart relay that would do that for me, or just suggest another device that’s smaller than the Sonoff one that may fit behind the switch without the need to deepen the back box.

 

[Chief Sawdust Maker]

An electrician is not permitted to sign off other peoples work.

I am a qualified instillation engineer all be it a long time ago. 3 years ago I constructed my wood working workshop. In order to keep costs down i wanted to do the electrical work myself, I contacted around 7 local electricians none of whom would test or sign off any work I had done, which I fully understand.
I ended up employing an electrician to do the second fix testing and sign off, I installed all the trunking, conduit, light fittings and boxes myself with him specifying the materials to use. Watching him do the 2nd fix with regards to termination of cables sizing of mains incoming cables and the make up of the distribution board, times have changed things have moved on and regulations do not stand still. An example being that plastic conduit is secured with metal saddles.

The only mention you made with regards to testing was that of continuity, which does not cover all of the tests required for additions or alterations to a fixed wiring circuit.

The guidance and information is that don't do what you were suggesting and get a qualified electrician in to do the job

With regards to condescending If you take the bullet points of guidance and safety in that way then that's up to you.

The fact that you raise taking 13amp into a lighting circuit would indicate that you do not have that greater knowledge or experience in electrics.

I hope you remain safe

 

[Spectric]

I was hoping for suggestions rather than the usual “just pay a spark”.

So you would need the relevant test equipment to be able to undertake the work safely and also know how to use it and interpret the results, now a half decent multitester is going to cost at least £500 for domestic so maybe getting that sparky in with his experience and knowledge is not really that expensive after all.

 

[Luckosaurous]

An electrician is not permitted to sign off other peoples work.

I am a qualified instillation engineer all be it a long time ago. 3 years ago I constructed my wood working workshop. In order to keep costs down i wanted to do the electrical work myself, I contacted around 7 local electricians none of whom would test or sign off any work I had done, which I fully understand.
I ended up employing an electrician to do the second fix testing and sign off, I installed all the trunking, conduit, light fittings and boxes myself with him specifying the materials to use. Watching him do the 2nd fix with regards to termination of cables sizing of mains incoming cables and the make up of the distribution board, times have changed things have moved on and regulations do not stand still. An example being that plastic conduit is secured with metal saddles.

The only mention you made with regards to testing was that of continuity, which does not cover all of the tests required for additions or alterations to a fixed wiring circuit.

The guidance and information is that don't do what you were suggesting and get a qualified electrician in to do the job

With regards to condescending If you take the bullet points of guidance and safety in that way then that's up to you.

The fact that you raise taking 13amp into a lighting circuit would indicate that you do not have that greater knowledge or experience in electrics.

I hope you remain safe

The only work I’ve done so far is replacing existing light fittings and removing existing plugs sockets that were spurs. I haven’t added anything to any circuits.

I accept this was a silly suggestion, as I said, I posed it more to start the conversation in the hope that someone could offer a solution that may work.

It seems as though the consensus is that even the safe but more work solution of making the back box deeper and adding a relay there isn’t being met with approval either. What would the danger be in adding a smart relay that bypasses the switch such as this? Is there something I’m missing that would make that option unsafe?

 

[MarkAW]

Don't do it.
Circuit alteration requires Part P notification.

You could use smart devices that don't need electrical system changes, get a qualified electrician, or attend an electrician course.

It's a case of 'you don't know what you don't know', and that's dangerous when it comes to things that can kill.

 

[Luckosaurous]

Don't do it.
Circuit alteration requires Part P notification.

You could use smart devices that don't need electrical system changes, get a qualified electrician, or attend an electrician course.

It's a case of 'you don't know what you don't know', and that's dangerous when it comes to things that can kill.

The only devices that don’t require touching the circuit are smart bulbs, but the problem with those is that when the switch is off they don’t work. They usually require a permanent live feed and so then the relay would tell a hub to tell the bulbs not to illuminate any more, but they would still be live.

So is the general consensus that I shouldn’t even add a relay to the back box myself?

Forgive my naivety, but where is the danger in that? If all of the terminal’s are connected correctly and there’s no exposed wiring in the back box. What is the potential danger that I’m missing here?

 

[Daniel2]

Don't do it.

You are potentially putting yourself, your family, your property and any tradesman attending your property at risk.
You are in danger of voiding your house insurance,

It's a case of 'you don't know what you don't know', and that's dangerous when it comes to things that can kill.

Very sound advice & guidance.
I know it can be difficult to accept what we are being told sometimes, but the people
offering it have no other agenda, other than you and your family's safety and well being.

 

[MarkAW]

Yeah I think in the non wiring scenario, you have to instruct people in your household not to turn off the switches, and to do it the 'smart' way instead. Though that doesn't always work. At my friend's house he has that setup, when I look after pets when my friend is away and I've no idea how to control his set up so I have to switch off at the light switch.

I couldn't possibly answer your question on adding the relay. I'm not certified and I don't know enough about electricity.