Low voltage house wiring

Hello. Has anyone wired their house with low voltage (5V or less) in order to be able to easily connect sensors, camera or displays in pretty much any room? I’m no electrician, but I think to remember from my uni years that the wires would have some resistance which would cause a drop in voltage.

Thanks in advance for sharing your solutions and experience.

I’m using Power over Ethernet (PoE) with appropriate injectors, switches or taps to provide low voltage where necessary. Run wiring according to PoE specs. Instant low voltage. 5v, 12v (other voltages) and USB format taps are cheap and readily available and make it easy.

Wiring with 5v is actually pretty tough. Voltage drop over the wire quickly becomes a problem at such low voltage.

I wired with 12v, which is still quite a safe voltage and allowed by most code jurisdictions - then drop to 5v at each device using a cheap buck converter. Most of the sensors you want to use are likely designed for USB power to 5v is perfect.

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Yes, I have 5V and 12V distributed around the house in a star pattern. Each device gets it’s own cable back to the supply.

The load currents to each device are quite low (ESP devices, smoke sensors and PIRs mostly) so there is little loss even over CAT5 cable or two pair telephone cable.

Supply monitor:

EDIT: If you want to reduce your cabling and run a bus with droppers for devices, run 24V everywhere and use DC-DC converters for 5V and 12V at the locations you need it. Power loss is proportional to current squared. So higher voltage, lower current gives you better efficiency, even allowing for the loss of the DC-DC converter.

Thanks everyone for your suggestion. I guess I should consult with a local electrician anyway, as I have no idea what are the building/safety regulations. (I’m leaving in the UK, in case anyone can comment on the regulations)