DIY Doctor

UK Wiring and no Neutral for Smart Light Switch Installation

Postby Yammers » Wed Feb 12, 2020 11:49 am

Hi there

I am thinking about installing a smart light switch, however, there appears to not be many no neutral version.

Is it legal and possible to create a false neutral? What I mean by this is as follows

From the Live cable place a 3 way wago connector block, 1 live will then go to the switch as per normal, in the 2nd slot I would place a neutral coloured cable into the wago block then connecting the blue cable to the neutral on the switch.
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Postby Mr White » Wed Feb 12, 2020 6:58 pm

Just because a wire is a certain colour does not mean it is what the colour indicates it is.

So just because you (now) have a blue wire does not mean it is neutral, as it is connected to live, it will still be live.

You are also finding out that most smart switches require a neutral, and from what I read, most smart switches that do not require a neutral often
"go wrong"
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Postby ericmark » Thu Feb 13, 2020 1:41 pm

I have MiHome Energenie light switches which don't need a neutral, however as @Mr White says there are problems, to do without a neutral a very small amount of current flows through the bulb all the time, bulbs designed to dim will normally have a leak resistor or capacitor so this small current will not light the bulb, so the switches will work OK, so with BA22d 10W bulb it worked A1, even with 8 x E14 and 5 x E14 bulbs not dimming type it worked OK.

However with G9 bulbs I had to fit a 4 uf capacitor from CEF designed for the job to stop lights flashing when switched off, and both the G9 and MR16 bulbs every so often start to pulse, not sure why, but intermittent and since I have many GU10 found swapping some bulbs between standard switch controlled and smart switch controlled got rid or the problem, but with G9 bulb it would be an expensive experiment to find bulbs which do not pulse, and because they don't pulse today does not mean they will not pulse tomorrow, seems an intermittent fault.

The other problem is MiHome Energenie will work direct with a remote control up to 3 of them, but to work with a phone, PC, tablet, or Nest Mini it needs a hub. And if you watch the Santander bank advert with Stan the way it gets it all wrong, that is very true, we have said hay google turn off the radio, and it replies turning off 5 switches and the lights go out, but ask it to turn them on again it says don't know how to do that yet.

From time to time the living room light switch has required a re-boot, non of the others have needed this and all the same, but every so often living room switch will not switch off, if I then switch off at the consumer unit count 5 and switch back on, it will work OK for a few months.

The MiHome Energenie 13A sockets have never had a problem, uses same hub and remote controls, but they have worked A1 as have the TRV heads which control the heating also same hub, and the energy monitors also same hub, only the light switches with no neutral have caused problems.

However since the same hub and app is used for many items, you need to consider all together, so it is often a compromise, likely EvoHome is best central heating control, but not seen their sockets or light switches.

Using Sonoff in the ceiling where there is a neutral maybe an answer, but often they need a box to be mounted in.

Personally it all started with my mother and an alarm to tell us if she went out in middle of the night, tried a remote controlled socket, but would forget to turn on again, tried a timer but then some one would come to door and we would have to run upstairs to switch off before answering the door, the smart socket combined both time and remote control so got smart socket, and since also a problem with central heating also fitted smart TRV heads at same time which were claimed to work with Nest, and my son had said how good Nest was, did not actually try linking with Nest until we moved, and by that time Google had taken over Nest and removed support for MiHome Energenie so they work of sorts, but not how they were claimed to work.

However this is not only MiHome Energenie, seem reports that the Hive TRV heads have also had problems sending messages to the wall thermostat, and lack of power to work some TRV bases.

But the problem is to get anyone who has bought some thing that does not work A1 to admit it. So you get some one singing the praises of Hive you ask how well do the TRV heads work, then they admit they don't have any, so only half a system anyway.

Lightwave seem to get good reports, I think they use a battery in the switch, Easy Switch does the same, and MK kinetic uses the energy generated moving the switch, most electronic switches need a master/slave set up for 2 way.
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Postby ericmark » Thu Feb 13, 2020 10:57 pm

Sorry error, lightwave don't use battery in main switch, only the wireless slave switch needs a battery. But not cheap both lightwave and energenie need a hub which boosts the price.
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