Powering a Nest Thermostat with Alarm control panel power cables....

oxygen · 30-03-2016 10:18AM #1

Hey. A while ago I got my house rewired. Cables were all chased into the wall. This included wiring in for an alarm. Each room has a white wire in the corner for sensors to be fitted. There are also two white cables by the front door where the electrician said the control board could be mounted.

Im assuming those wires will power the control board, my question is would they power a Nest Thermostat? Is the power consumption the same. I don't like the idea of a black power cable running down to the nearest plug if I install a nest by the front door.

The power requirements for a NEST are "as it does to keep your mobile charged"

Thanks!

Pete67 · 30-03-2016 10:54AM

Most likely no. While the power requirements are very low the Nest requires mains voltage (230 VAC) to operate and this can not safely be supplied by alarm cables, which are intended to operate at low voltage. Also bear in mind that the thermostats should be located in a central location away from doors and windows and out of direct sunlight so that they measure a representative temperature. Locating them beside the front door is not an ideal location as it will likely be colder than the rest of the house.

Seanmk1 · 30-03-2016 10:57AM

European Nests need a mains voltage supply.

I believe that in the US they use 12V dc or similar. I was waiting a long time for the mains version to come out and pretty much bought it as soon as it did.

Sleamhain · 30-03-2016 10:59AM

oxygen_temp wrote: »

Hey. A while ago I got my house rewired. Cables were all chased into the wall. This included wiring in for an alarm. Each room has a white wire in the corner for sensors to be fitted. There are also two white cables by the front door where the electrician said the control board could be mounted.

Im assuming those wires will power the control board, my question is would they power a Nest Thermostat? Is the power consumption the same. I don't like the idea of a black power cable running down to the nearest plug if I install a nest by the front door.

The power requirements for a NEST are "as it does to keep your mobile charged"

Thanks!

Did the electrician not wire/install a thermostat in the house? You can replace the existing with the Nest if there is one there!

Also, installing the Nest by the front door is probably not ideal due to drafts lowering the temperature readings when the door is opened!

Seanmk1 · 30-03-2016 11:06AM

You're right about the drafty hall being a bad place.

With Nest you fit the "hub" ( I think it's called ) over the old thermostat and put the new thermostat wherever you like. They then talk to each other using a wireless connection.

You need a 230V supply at both locations.

g1983d · 30-03-2016 11:09AM

The nest comes in 2 parts, the control unit which would be near the valves or controller in your boiler room or hot press, this is 230v and has a 12v output for the stat. The 2nd part is the thermostat itself which is 12 volt.
I have them in my house and wired them with Cat 6, I did this while building as cat6 didn't need to be certified by an electrician which kept the cost down, alarm cable should work also just use 2 cores for positive and negative (see pic).
I wouldn't put them near a door either as they won't work as well.
Alarm cable would work fine also and if there's no cable near by then you can also power them with the mains plug that comes with them

g1983d · 30-03-2016 11:11AM

The nest comes in 2 parts, the control unit which would be near the valves or controller in your boiler room or hot press, this is 230v and has a 12v output for the stat. The 2nd part is the thermostat itself which is 12 volt.
I have them in my house and wired them with Cat 6, I did this while building as cat6 didn't need to be certified by an electrician which kept the cost down, alarm cable should work also just use 2 cores for positive and negative (see pic).
I wouldn't put them near a door either as they won't work as well.
Alarm cable would work fine also and if there's no cable near by then you can also power them with the mains plug that comes with them

Seanmk1 · 30-03-2016 11:13AM

You need to check if your thermostat is 12V or 230V. Mine switched mains voltage.

g1983d · 30-03-2016 11:26AM

The nest comes in 2 parts, the control unit which would be near the valves or controller in your boiler room or hot press, this is 230v and has a 12v output for the stat. The 2nd part is the thermostat itself which is 12 volt.
I have them in my house and wired them with Cat 6, I did this while building as cat6 didn't need to be certified by an electrician which kept the cost down, alarm cable should work also just use 2 cores for positive and negative (see pic).
I wouldn't put them near a door either as they won't work as well.
Alarm cable would work fine also and if there's no cable near by then you can also power them with the mains plug that comes with them

oxygen · 31-03-2016 11:01AM

ah ok, thanks for the replies guys. There is way more to this than I thought so. I'm sure I must have an existing thermostat as the house was also re-plumbed as well as rewired, the hot tank is in the main bedroom. (its an old house) there is access to it.

So I think my options are,

1. Wiring the Nest control unit by the front door, This would look cool, but as mentioned above though, if the thermometer is in the control unit, it would be a really bad place for it as the hall is always cold

2. Having the Nest control unit in the sitting room, this would be the preferred option since the temp of that room is what I usually want to keep the house at. Also I can just run a wire up to the book case it would be on...

cerastes · 01-04-2016 10:33PM

Pete67 wrote: »

Most likely no. While the power requirements are very low the Nest requires mains voltage (230 VAC) to operate and this can not safely be supplied by alarm cables, which are intended to operate at low voltage. Also bear in mind that the thermostats should be located in a central location away from doors and windows and out of direct sunlight so that they measure a representative temperature. Locating them beside the front door is not an ideal location as it will likely be colder than the rest of the house.

Out of curiosity, what voltage? 12v AC?

g1983d · 02-04-2016 08:11AM

cerastes wrote: »

Out of curiosity, what voltage? 12v AC?

Alarm components operate at 12v also.
In alarm panels there is a 12v backup battery also

cerastes · 03-04-2016 01:03AM

So it's DC? only?

What about the part of the nest that is 12v? DC also?

g1983d · 03-04-2016 09:31AM

cerastes wrote: »

So it's DC? only?

What about the part of the nest that is 12v? DC also?

The stat on the wall can be powered from the control unit at 12v or from the mains using the supplied micro USB cable and mains adaptor.
Not sure what rating the mains adaptor is though off the top of my head, I use the ones that came with my nest as a spare phone charger :-)

Powering a Nest Thermostat with Alarm control panel power cables....

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