Reeds switch cable to window and doors

[Rollover77]

Hi all,

My house is currently stripped for a renovation and I want to use the opportunity to run cable to windows and external doors to then use reed switches. The cable will go back to the under stairs and connect to an ESP-32 unit to process the state of the reed switches. The ESP runs on and provides 3.3v.

To minimize cable runs to/from the under stairs, I want to connect reed switches in the same room in series and have one 'room' cable back to the under stairs.

I have some 75mm 2-core flex for the run to the room from the under stairs, but am not sure what to use to jump from switch to switch. I only need one core for this.

What would be an appropriate cable to use, can I just take the brown core out of the 2-core flex? I want to run it under floorboards and up/down stud walls that will be plasterboarded so it will be hidden. Is this within regulations?

Similarly, what junction box can I use to make the connection to/from to the 2-core at the start/end of the room loop? Again something that I can safely (and legally!) attach to the side of a joist and have hidden

Many thanks for your help!

 

[chivers67]

If it's only 3.3V can you not just use a telephone / data or Bell wire? To join a Wago box with ends doubled over or even an inexpensive joint box. Staple gun the cable? Or cleats should be fine.

 

[Rollover77]

If it's only 3.3V can you not just use a telephone / data or Bell wire? To join a Wago box with ends doubled over or even an inexpensive joint box. Staple gun the cable? Or cleats should be fine.

Thanks for the reply. I’ll use whatever is suitable really, just wasn’t sure what is and isn’t allowed to be concealed inside the ceiling / under the floor.

If it’s only 3.3v is it fine to use those wires and have them hidden then?

Thanks again

 

[flameport]

If it’s only 3.3v is it fine to use those wires and have them hidden then?

Cables must be installed in the appropriate zones and must be properly supported. That applies to all cables, whether they are for 230V power, communications or anything else.

The ESP runs on and provides 3.3v.

If you are intending to have cables directly from the 3.3V logic inputs to switches or other devices elsewhere in the building, there will be a pile of problems.
The lengthy cables will act as antennas, picking up all kinds of interference. If installed near to power cables, they will pick up voltages from those as well.
Using a single core looped between switches will magnify that effect significantly.

As an absolute minimum, twisted pair cabling should be used with one pair per switch, and it will need to have separation between the switches and the ESP32, such as using 24VDC for the switches and a converter to provide whatever signals the ESP32 requires.
A random example: https://www.amazon.co.uk/DST-1R4P-P-Optocoupler-Isolator-Isolation-Conversion/dp/B084ZNFN5R - this may not be suitable but it's an example of the general concept.

 

[Rollover77]

Cables must be installed in the appropriate zones and must be properly supported. That applies to all cables, whether they are for 230V power, communications or anything else.


If you are intending to have cables directly from the 3.3V logic inputs to switches or other devices elsewhere in the building, there will be a pile of problems.
The lengthy cables will act as antennas, picking up all kinds of interference. If installed near to power cables, they will pick up voltages from those as well.
Using a single core looped between switches will magnify that effect significantly.

As an absolute minimum, twisted pair cabling should be used with one pair per switch, and it will need to have separation between the switches and the ESP32, such as using 24VDC for the switches and a converter to provide whatever signals the ESP32 requires.
A random example: https://www.amazon.co.uk/DST-1R4P-P-Optocoupler-Isolator-Isolation-Conversion/dp/B084ZNFN5R - this may not be suitable but it's an example of the general concept.

Thanks, lots to think about there. What I may end up doing is having several ESP throughout the house and run each switch to the nearest as EOL (probably max 5m).

My concern with the cable was whether there are requirements with what type of cable can be concealed in a ceiling (suitably supported and appropriate for the load)