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greatalbatross

Home Wiring (lemmy.ml)

submitted 6 months ago by [email protected] to c/homeassistant

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This might be tangential to HomeAssistant but Im currently thinking about a household renovation and one thing I am considering is wiring.

I have some POE devices along with many other that run with a 12v DC supply.

I'm lookin at putting in a relatively straightforward 12v battery UPS with a small solar panel to charge. I probably only have space for 1500W of panels so putting in a whole grid tied solution is overkill. Primarily this is to provide backup as we sometimes lose power.

Networking wise I think I will put RJ45 into each room as we are concrete reinforced construction and so signal quality is an issue.

My query was how feasible it is to run both standard PEO devices and 12v devices (1-2w) all over POE.

I thought the alternative would be to run separate 12v cables with USB connectors at the end into each room as well as Rj45

Is anyone else doing this in their home?

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[–] [email protected] 9 points 6 months ago* (last edited 6 months ago) (2 children)

I’m using PoE Extractors to run some regular 12vdc stuff using existing ethernet cabling.

A couple of points to note:

network switches won’t turn on power by default unless the receiving device asks for it using the right protocols, so you need to inject the power using the corresponding PoE injector at the other end of the cable. you can’t just snip the end off a RJ45 and wire it into things.
Cat cable won’t take high currents, be sure to stick within the allowed range for the cable or it will melt and maybe bust your device
there is a voltage drop over distance, be sure to calculate if you need to change your transformer as 12vdc could become 9 or lower by the time it gets to your device
there are some really poor quality PoE injectors/extractors.
running mains cable and having a transformer nearer the device might be simpler and cheaper in the long run.

[–] [email protected] 2 points 5 months ago (1 children)

The specs for latest versions of POE go up to 60-100W which is way beyond what I expected. Is that just still running over normal Ethernet or should I be looking for specifically rated stuff?

[–] [email protected] 3 points 5 months ago (1 children)

You can get that kind of power through a Cat6a or Cat7 ethernet cable but a lower spec cable won’t work. here’s an article that talks about the limitations https://sixtytrend.com/can-cat5e-do-poe/

[–] [email protected] 1 points 5 months ago (1 children)

Really useful thanks. Definitely sounds like I will be thinking about the Cable Cat more carefully.

[–] [email protected] 3 points 5 months ago

definitely run two cables for each point. nothing beats having a cable be broken somewhere in the walls with no way to repair it.

[–] [email protected] 1 points 1 month ago* (last edited 1 month ago)

Just picking up a conversation a few months ago. I was wondering if Im over complicating this. I think the takeout from earlier conversations were 'Install conduit' i think a 12V DC supply + Ethernet + separate conduit for AC power..

but.. I also found POE injectors that look like thry take 12v as an input. (So potentially could run things from a battery/ solar supply ) https://a.aliexpress.com/_EG8apjq

Im not sure if they would be suitable though.