Powering a Nest Thermostat

[adzyp]

I’m looking to purchase a smart thermostat and looking at the nest or hive. I think I may be swaying towards the nest due to its learning capabilities but I don’t like the idea of having to plug it in. I don’t have a wired thermostat that I can replace and I don’t want to use it with a stand either. I’d like it to sit on the living room wall.

If I was to locate this next to an already existing light switch is it possible at all to feed off the existing wires for the switch to power the nest thermostat, make a small channel in the wall and therefore have no visible wires?

 

[oceansoul]

Is there a neutral at the light switch?

 

[adzyp]

Couldn't say for definite as im not at home but pretty sure that there is

 

[OwainDIYer]

Probably not.

The Nest Thermostat is powered by 12 volts by repurposing wires to the existing thermostat and connecting them via the Heat Link unit (which is also a 12 volt power supply), or by a plug-in USB power supply. The Nest Thermostat cannot be connected directly to mains voltage.

Also many light switches only have a live and switched live wire, no neutral, so you would not be able to take power from them anyway.

You could mount the Next Thermostat near a convenient 13 amp power socket and use D-line microtrunking up the wall to the 'stat.

The alternative is to run new 12 volt (bell wire) from the Heat Unit to the Thermostat location.

http://www.directheatingsupplies.co.uk/pdfs/Nest Thermostat Installation Guide UK.pdf

Edited to reduce confusion over low voltage / 12 volts and USB

 

[EFLImpudence]

Neutral is the name of the conductor which completes the circuit from the load back to the electrical source.
It is not a generic name for any black (or blue now) wire.
Wires can be anything we want; they do not know what colour they are.

240V is Low voltage.
<50V is Extra-low voltage.

 

[OwainDIYer]

240V is Low voltage.
<50V is Extra-low voltage.

I know, but calling mains low-voltage confuses people, especially when the instruction book says low-voltage for 12V.

 

[adzyp]

Ok, so now you mention it only requires 12v, based on my experience of installing my own outdoor low-voltage lighting system, an alternative could be to use a transformer that sits behind the sofa out of sight and i could then bury the low voltage cables in the wall

 

[EFLImpudence]

I know, but calling mains low-voltage confuses people, especially when the instruction book says low-voltage for 12V.

I know you know but perpetuating a mistake will not help and is equally confusing when you say it.


Just call it 12V or 24V and 240V.

I see the OP hasn't taken any notice.

 

[adzyp]

Sorry, i get you now. So its not 12v. But along the same principle. I'm thinking of using the included plug and wire, run behind the sofa and just extending the wires by adding more to the ends so that i can channel it into the wall?

What wire would i need?

 

[OwainDIYer]

Power from the Heat Unit is 12V so bell wire would be fine if you do it that way.

The plug-in power supply is micro USB -- I don't know whether it's power-only or uses USB signalling too. Nest says you need a micro USB cable to extend it.
https://nest.com/uk/support/article...r-cord-is-too-short-to-reach-the-power-socket

 

[muffking]

The plug-in power supply is micro USB - Nest says you need a micro USB cable to extend it.

That bit right there.
Just buy a micro USB extension lead to connect the Nest controller to the mains adaptor.