Hiding 12v PSU in dry lining box for Nest Thermostat

29 Jul 2010
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United Kingdom

I plan to buy a Nest thermostat, but because I dont have any 12v supply wires to the control box, I need to power the thermostat separately.

I dont like the USB PSU and Cable solution because it means the USB wires will be visible running up the side of the wall. I would much prefer the power supply to be hidden in the studwork itself.

Notwithstanding some folk wont like the idea of hiding a PSU in studwork, I was wondering if anyone had managed it?

i.e. A metal single-gang dry lining box, with a 230v to 12v PSU connected inside. The box can be covered over with a blanking plate. I can then run the 12v wires into the back of the Nest thermostat which should look far neater.

Has anyone done anything similar, and if so is it possible to purchase a 12v PSU which can fit into a single-gang dry lining box? (it would be ideal if such a part already existed).

Cheers in advance.
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I've only seen them in a double box ( for such things as nest , ring door bells / cameras ) the normal encapsulated cctv type power supply's
Whether it's 230V or 12V, wires are still required.

If you can conceal 230V wiring in the wall, why cant you do the same with the 12V wires?
Hi, thats the point. I do intend to conceal the 12v wires in the wall, but there needs to be a PSU somewhere to convert 230v to 12v. I dont want a power brick connected to a standard plug socket, hence my question about hiding a 12v PSU (like used as an LED lighting controller) in a metal dry lining box.
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I see your point, I have looked at USB sockets, but the USB needs to be plugged in outside the back box so there will always be a loop of wire, however I have seen my wife unplug the USB bricks and take to where she wants them. My phone left unplugged, OK to have flat phone, but to have the central heating hub unplugged is some thing else. So I use USB socket for central heating hub.

However still needs a LAN connection to router and not unknown for her to unplug switch to use vacuum cleaner so she still disables central heating, what I need is a switch that gets it's supply from USB.

But if you have 230 volt power then a USB outlet seems the answer, only question is how to get USB cable into wall in a neat way,
maybe a grid switch unit like shown, with a blank with hole in next to it with USB cable coming out?
I thought the OP was talking about 12V, and the type of USB you are are talking about is 5V.
There are some available that fit inside a 1 gang back box, I have something similar powering a wall mounted Honeywell Evohome controller.
Yeah thats what I was hoping for. I can buy a cheap 12v PSU for LED lighting dirt cheap on Ebay, though I dont mind paying a bit extra for something that is reliable etc.

The biggest requirement is that it fits into a 1 gang box.
Yeah thats what I was hoping for. I can buy a cheap 12v PSU for LED lighting dirt cheap on Ebay,
Do not buy one direct from China, or from a seller in China etc.

The problem is that Chinese manufacturers, and Chinese sellers, are outside the jurisdiction of the UK/EU, and far too many of them are making and selling dangerous and illegal products, lying about standards compliance, and so on.

Buying from a UK seller, who is importing from China, and who is bound by UK laws, or buying products from companies who have them made in China, but are bound by UK/EU laws, etc, is one thing, but going direct carries too many risks.
And what other sort of USB charging voltage is there?
USB now has Power Delivery (PD) available when provided via type-C connectors. This will supply up to 100W, at voltages ranging from 3.3V up to 20V.
You may be right that 5V is an option; I was going by the "12V" statement, and I know nothing about Nests, nor do I really want to!
A separate PSU has been used before. You can read the thread here. The bit about the PSU is towards the end.

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