Swapping to POE switch
from westingham@sh.itjust.works to homelab@lemmy.ml on 28 Sep 2025 13:03
https://sh.itjust.works/post/46920642
from westingham@sh.itjust.works to homelab@lemmy.ml on 28 Sep 2025 13:03
https://sh.itjust.works/post/46920642
I live in a house that has CAT 5 cable in the walls running to wall plates in various rooms.
Would it be possible to remove the existing regular switch, replace it with a powered POE switch, and then plug in a POE device into one of the wall plates?
Also, for the non-POE devices already plugged into wall plates, would they be okay?
I’m trying to wrap my head around the interoperability of POE and non-POE and struggling.
threaded - newest
Yes, the switch should detect that its not a POE device and not send power. I’m not sure how it would work if the port is wired incorrectly though, so worth checking if you have access to a detector. Electricians are notoriously bad at wiring Ethernet correctly.
Bear in mind, the POE switch will generate more heat, so if its in a closet with no airflow, it might overheat.
Grilled a Brother printer mainboard thinking that, so don’t be too sure of that autodetect.
Yes. There won’t be a problem, assuming that the devices in question are indeed ethernet devices and not just using cat5 wiring. That said you will need to be aware about what kind of PoE device you are plugging in. There are several evolutions of the PoE standard.
802.3af 802.3at 802.3bt
So make sure that if the devices requires 802.3at, the switch is rated to provide that.
Good answer.
Just chipping in to point out that there are a LOT of products listed as “POE” that don’t comply with any official standard, and are just designed as a single pair for lower end devices. So to echo your advice, do check for standards before buying.
The idea was to swap in a Ubiquity POE switch so i could power a Ubiquity AP and some POE cameras throughout the house
Sounds good; known branded equipment is more likely to be compliant - but do check, it’s usually pretty clearly marked on packaging and listings.
And most importantly, you do NOT want anything that does passive POE, because it puts 48v on one of the pairs, which will zap any equipment not expecting it.
Check out MoCA adapters. You need one for each wall plate you want to convert and one for the modem side. Check out this site for a diagram and more info.
That’s for coax, OP did not mention coax
Oh man, must’ve been pre-coffee brain. Thanks for the correction.
All good answers, one thing not mentioned is that there are smart/managed switches where you can toggle PoE on/off per port on the network switch. Could be useful, sometimes it’s best just to never provide power on any network ports until you know you need it.
Fyi there ar multiple standards for Poe with different voltages and some Poe switches only does one or maybe two standards (most often at 48-57 V) but if you have older/cheaper Poe devices they might use passive Poe at 24-38V and not all switches supports that mode simultaneously with the more modern Poe standards. Some switches will “support” both modes but only one mode at the time for all ports or maybe its just pasively passing on the input voltage as output voltage. Luckily most Poe switches support auto detection (unless its a crappy no name brand) and having that feature will protect your non Poe devices from damage. Poe is detected by some specific resistance steps on the wires (don’t quote me) but this means if you have very long wires auto detection might not work but that will always default to off. You can usually on a proper brand switch force a port to be on but then be sure to physically mark that port with a sticker or something saying it’s “HOT” because then there’s no protection for non Poe devices any longer.
I won’t recommend any switch for you at the moment untill I know more about your skill level and use case.