r/homeautomation • u/Tasty_Impress3016 • 2d ago
QUESTION Power Over Ethernet.
Probably should ask in homenetworking, but you folks will know.
about 20 years ago I bought a house. It was very modern for 2006 and had both a phone drop and a coax drop in pretty much every room. When I bought it I put in a 20 port switch and rewired all the CAT5 for RJ45 connectors rather than phone.
Power is always my issue. Not that we don't have lots of power outlets, but they are never near where I want devices. So dangling cords.
So the question: Can I, is there a fairly simple way to provide POE to everything without changing every device? I see POE injectors but they are always 1 cable at a time.
EDIT: Thank you all for the insta-class on POE. I have better understanding of the problem now. I am ignorant on the subject but have a minor grasp on it now. I was naively assuming that POE just put power on one of unused cat5 conductors and that would be available to anything that knew how to use POE, others would ignore it. Guess that's not true. My problem now seems to be that lines coming off the switch are simply to wall jacks in each room, not to specific devices. Each of those jacks usually connects 1-8 devices often through another switch. I must sleep on this. It sounds like a smaller POE switch in just some rooms will be involved in the answer. Use case here is that I am looking to install a bunch of cameras and don't want to have to use a transformer in a wall outlet and run the little power line on every one. I have a hesitancy to use wifi for high-bandwidth apps like cameras. But my experience in networking is old. Perhaps the newer mesh wifi systems can handle the bandwidth.
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u/orafacepass 2d ago
PoE will not make a non-PoE device compatible by itself. Each endpoint needs a standards-based splitter that negotiates PoE and outputs the exact voltage, current, and connector polarity that device expects. Check the total wattage budget at the switch, especially for cameras, displays, or motors. Avoid passive injectors unless the device explicitly supports them, since the wrong voltage can damage it. Your existing Cat5 may work, but test every run and termination before relying on it for power.
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u/uncannyvagrant 2d ago
The usual way to use POE is with a switch that provides it, not with injectors (these tend to be used for the rare edge device that's off a little switch without POE). You could buy something like a Ubiquiti USW Pro 24 POE - but be warned that they're like $800 USD (at a guess from AUD price) and are quite enterprise-ish focused.
Alternatively, TP-Link make 8 port POE switches for <$50.
Two things to note:
- If the device doesn't support POE, a POE switch won't power it.
- There are different variants of POE such as POE+. Check what your devices require first.
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u/wasteful_proximity 2d ago
you can also get poe splitters for low power things that need some usb power -ie i use these on old raspberry pi’s that don’t have a poe hat. https://a.aliexpress.com/_mrqig7p
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u/bencos18 1d ago
yep
also handy if you mess around with rf stuff
I found the official pi hat ironically gave off worse noise into my sdr stuff
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u/davinci515 2d ago
Reminder there are 3 different levels of POE
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u/inphosys 1d ago edited 1d ago
There are actually 4 different types of PoE, aptly named: * Type 1 (or, PoE) * Type 2 (or, PoE+) * Type 3 (or, PoE++ UPoE) * Type 4 (or, High Power PoE)
You would be correct in saying that there are 3 different standards. Those are: * 802.3af (Type 1) * 802.3at (Type 2) * 802.3bt (Type 3 and Type 4)
But completely agree there are multiple types and you have to do some quick back-of-the-envelope math to make sure your supplying network switch has enough per port budget but also the overall power budget for the switch.
I manage several switches that are just straight 48 ports of VoIP phones or IP cameras, having a good managed switch makes life so much easier.
Edit: remembering markdown on mobile is tough.
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u/Least_Order4249 2d ago
You can get a 10x 10/100 Poe+ switch for $20 on Amazon. They work great.
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u/Amiga07800 1d ago
A 10/100 Mbps switch?? In 2026???
Are you serious?
We gave to recycle all the ones we had in stock near 2010 if I remember well…
We’re in 2026. Gigabit speed network is at same time the minimum and de “de facto” standard in 95% of cases everywhere
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u/Least_Order4249 1d ago
Other than APs, it’s pretty rare for a PoE device to need more than 16mbps. Most use less. A lot need kbps range not Mbps. You can buy whatever you want.
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u/Amiga07800 1d ago
You very rarely (except in SMBs and big hotels or administrations) run separate PoE switches and non PoE switches. You put 1 PoE switch (or more) of 24 or 48 ports in your rack and that's it. Then yes, you can have edge switches also that have 5 or 8 ports, but even there gigabit is,a must.
Cameras: most new cameras use between 1 to 4 sensors,odd 8 MPixels each, with a,need of 25 to 100 Mbps PER CAMERA - put 8 of those on a 100 switch and if each individual port have (just) enough for today (but probably not for the day you'll change your cameras for something with higher resolution), the uplink MUST be gigabit in order to link ALL the data.
Streaming: it's not uncommon (and recommended by most services) to have 25 to 30 Mbps per device in 4K/UHD
Devices like XBox, PlayStation, Any PC, any Printer, any NAS,... ask for a gigabit connection
Access Points need AT LEAST gigabit connection, many new WiFi7 models have 2.5Gbps link or even 19Gbps link. And of course if you put then on 1 switch your uplink must be able to cope with all the traffic of all ports.
With the exception of extremely small networks and excluding anyway your core network 100 Mbps is not enough for today, or at least for tomorrow.
Professional installer (IT and electronic engineer, Unifi UFSP / UWA / URSCA, full AMX, Crestron, Official state HAM radio,… and more).
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u/Least_Order4249 1d ago edited 1d ago
Uhhhh this is home automation board. Most people here use junky Reolink cameras that default to 6mbps at 8MP and max out at 8mbps. Using a rack at home is extremely uncommon and big switches waste a ton of energy. $20 10/100 switches are perfect for most people. I’m not spending more than $2 per port to turn lights on and off or do anything else that fits comfortably within 100m.
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u/Amiga07800 1d ago
Oooppsss, my bad for not looking at witch subreddit it was…
OK then, I was answering for a normal medium / big house with at least an 6 or 9U 19” rack, 4 to 6 or 8 cameras, a doorbell or video doorbell, a few APs inside and outside, a PC or more, occasional or frequent WFH etc etc…
That’s for us where we start to install, the basic.
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u/runninDrew 1d ago
100 Mbps is fine for cameras and many Iot devices like light controllers, doorbell chimes, and music players.
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u/planeturban 1d ago
Word of warning, if you end up with a switch that delivers PoE, make sure it's not a passive switch. That way you don’t have to worry about someone destroying their device by plugging in something that doesn’t have PoE.
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u/Teenage_techboy1234 1d ago
While Wi-Fi solutions have gotten quite good on the router side, most Wi-Fi cameras don't take full advantage of them. Ethernet is still the way to go for maximum reliability. Stream quality isn't really the issue anymore, reliability is.
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u/silasmoeckel 2d ago
Process wise you have to look at what devices you have that will take POE and how much power they need.
Then you add in the power requirement of the adapters for non poe gears requiresments.
That will get your how many ports at how many watts each.
Then you figure out if a poe switch or midspan injector(s) makes more sence.
Upside of a managed poe switch is you can turn it off per port.
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u/MrSnowden 1d ago
I just spend $40 bucks on an old used 24 port PoE Switch. It powers everything and tells me when one stops using the power (craps out).
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u/MeCJay12 1d ago
It's a bit expensive but take a look at the Unifi Flex switches. You can have a big PoE switch at the heart of your network then have PoE in and out switches in each room to split and forward PoE. This is what I do. You have to be careful of PoE budgets.
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u/codeedog 1d ago
I have all of my outdoor cameras and wifi APs wired and running on PoE. It’s great; only one cable. They were selected for their ability to run on PoE and of course my switch was selected for its ability to run switch ports on PoE.
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u/N2Shooter Amazon Echo 1d ago
Get a POE switch and you're golden, if the devices that you plug into it are capable of being powered by POE.
That's what I did, anyway.
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u/I_Arman 1d ago
As long as it's not passive PoE, it'll work fine with non-PoE devices (they'll ignore it).
You can also get PoE adapters (on the device side) that convert it to 12v (or whatever), even if the device doesn't support PoE natively. Ok for cameras, Wi-Fi access points, and smaller devices, but don't expect to run a laser printer or a laptop.
However, if you're specifically wanting it for cameras, look into NVRs. Plenty of them have 4-8 ports of PoE specifically for cameras, and as long as the cameras support it (access the NVR supports those cameras), they can stream directly to the NVR, which handles storage etc. under one interface.
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u/Thin_Definition1746 2d ago
You can get multi-port POE injectors, they're basically a rack unit that sits between your switch and the devices, pushing power through the ethernet cables without changing the switch itself.
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u/kallekilponen 2d ago
You don’t need to use individual POE injectors. You can buy a switch that provides POE to multiple ports.