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Power over Ethernet (PoE) Explained: Why It’s Your Wi-Fi’s Best Friend

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So, you want to blanket your sprawling property with fast Wi-Fi, but extending electrical power to the far side of your yard or that tight corner in your attic proves mission (close to) impossible?

Don’t give up! That is when PoE, or Power over Ethernet, comes into play. This straightforward concept kills two birds with one stone.

There’s quite a bit to know about PoE, and you’ll find it all here, with a minimum amount of technical jargon.

Dong’s note: I first published this post on March 5, 2019, and updated it on August 16, 2021, to add up-to-date, relevant information.

EnGenius EWS850AP Wi Fi 6 Access Point 14
An example of a Power over Ethernet (PoE) end-device (PD)

What is Power over Ethernet

Power over Ethernet is when you use one network cable — CAT5e, CAT6, or a higher grade — to deliver data signals and electric power to a device.

Yes, you still need to run a wire — but only one in this case. Plus, network cables are much easier to install than electrical wires — you won’t need an electrician.

PoE: Cables and device types

PoE works with all network cables. Generally, though, a higher-quality cable (pure copper) is always better for PoE than a lower-quality one (copper-clad aluminum).

As for network speed, PoE adheres to the general standards of network cables. Currently, PoE is available from Fast Ethernet (10/100 Mbps) to 10Gbps Multi-Gig.

But PoE involves more than just that cable itself. Let’s find out.

Generally, when plugging a device into power, we involve three items: the power source, the electrical cord, and the device itself.

Since we can’t connect a network cable directly into a wall socket, we need something at this end to facilitate the power draw.

In the world of PoE, this device, the one that delivers power, is officially called the power sourcing equipment (PSE). For the sake of simplicity, we’ll call it the power sender.

On the other end, the device that gets electricity over the network cable is officially called a powered device (PD) or a power receiver.

PoE power sourcing equipment (PSE) – Power sender

A power sender is a device that works as a power source. It has a power adapter to draw juice from a wall socket. Typically there are two main types of PSE:

  • PoE switch: This switch looks and works just like any network switch, but with PoE-enabled network ports. Some routers also have PoE ports.
  • PoE injector (or PoE adapter): A kind of Ethernet coupler that also plugs into a wall socket.

Injectors are popular because they add PoE capability to an existing regular switch or router.

The PoE injector that accompanies TP-Link access points.
A typical PoE injector (adapter) has two network ports. You connect the PoE device to the injector’s PoE port and use its LAN port to connect it to a non-PoE switch or router. The injector itself has a power adapter to get power to the PoE device.

PoE power device — Power receiver

A power receiver is the end device — such as an IP camera, an Wi-Fi access point, or a Voice over IP phone — that’s PoE-ready.

You connect the other end of the PoE-ready network cable mentioned above to this device, and it’ll get both power and data signals.

Unlike the case of the PSE (power source/sender) above, you can not add PoE capability to an existing device to turn it into a PoE power receiver.

On the receiving end, the device itself needs to have built-in PoE capability from the get-go. Also note that a PoE device must connect directly to a PoE power sender with no active device, such as a non-PoE switch, in between. But a PoE connection works through a patch panel or a network coupler.

There is also hardware that works both as a PSE and a PD, for PoE Forwarding. An example is when a PoE camera has a second PoE-ready network port to power another PoE camera in a daisy-chain setup.

For this to work, the first PSE must deliver enough power for both PoE devices, bringing us to different PoE standards.

Power over Ethernet standards: Range and wattage

There are two types of PoE, active and passive. Both have a range of about 300 feet (100 m), which is the general max length of the network cable that connects a power sender and a power receiver.

Active PoE

Active PoE provides a safety mechanism for end devices (PDs).

With active PoE, devices perform a power check, called a handshake, before power is delivered. As a result, if the incoming electricity doesn’t meet the requirements, the power receiver won’t power up.

There are three primary standards for active PoE, including IEEE 802.3af, IEEE 802.3at, and IEEE 802.3bt. Since IEEE is short for the Institute of Electrical and Electronics Engineers, we can leave it out of the names for short.

802.3af

Also known as Type 1 PoE. This standard is the original (defined in 2003) and is still popular. It can deliver up to 15.4 watts of electrical power. In real-world usage, however, generally, you can expect about 13 watts from it.

802.3at

This standard is also known as PoE+ (PoE Plus) or Type 2 PoE. Available starting 2009, 802.3at provides up to 25.5 watts of power.

The 802.3at standard is backward compatible with 802.3af — its power senders (PSE) can support 802.3af receivers (PDs).

However, 802.3at power receivers (PDs) generally require an 802.3at power sender to work.

802.3bt

The 802.3bt or 802.3bt-2018, as the name suggests, became available in 2018 and further expanded the power capabilities of 802.3at. It has a few other names, including PoE++ (PoE plus plus) and 4PPoE.

802.3bt has two power outputs: 51W delivered power (Type 3 PoE) and 71.3 W delivered power (Type 4 PoE).

The 802.3bt standard’s power sender (PSE) is backward compatible with power receivers of previous active PoE standards. When applicable, it can easily deliver power to multiple PoE devices of lower standards in a PoE Forwarding setup.


The main advantage of active PoE is when a device belongs to a particular standard, it will work with all equipment of that standard from any vendors.

On top of that, a standard end device (power receiver) will work with any standard power sender of the same or higher tier. Newer standard PoE power devices might work with a lower-tier standard power sender but at a lesser capability.

But being part of a standard can be restrictive, and making standard devices means you have to adhere to all sorts of requirements — it can be expensive. This is where passive PoE comes into play.

Passive PoE

Generally, a passive PoE device is one that doesn’t belong to one of the 802.3x standards mentioned above.

This type of PoE generally uses a proprietary injector that accompanies an end device (power receiver) and only works with that particular device.

Passive PoE doesn’t adhere to a standard, and the vendor has the freedom to specify its own electrical specs. With passive PoE, electricity is passed to the end device (PD) immediately without a compatibility check.

For this reason, generally, it’s a good idea not to use a passive PoE injector with an active PoE receiver and vice versa. That can be similar to plugging a 110V device into a 220V outlet.

So, if you choose to use a passive PoE end device, only use it with a passive PoE power sender that comes with it.

But before you get scared, the good news is, for ease of use, many passive PoE end-devices (PDs) on the market also support a particular active PoE standard.

PoE Passive vs Active
Many PoE devices support both Passive and Active PoEs.

Extra: PoE sourcing equipment (PSE) and non-PoE device

If you wonder if you can use a non-PoE networking device, which most networking devices are, with PoE sourcing equipment — or power sender — such as a PoE switch. The answer is this depends.

Basically, any standard (active) PoE PSE also works as non-PoE equipment. So if you plug a non-PoE device, such as a printer, into a PoE switch, it’ll work just like when you plug it into a non-PoE switch. In this case, the PoE switch is smart enough not to deliver any charge.

However, generally, you don’t want to use a passive PoE power sender with a non-PoE device. In most cases, nothing will happen, but you never know.

The good news is that a passive PoE injector (adapter) generally only accompanies a device that needs it. As a result, the chance you’d use one with a non-PoE device by accident is low.

In short, the extra cost aside, it never hurts to get a standard PoE switch, even if you don’t have any PoE devices yet. You can use such a switch with both PoE and non-PoE equipment.

Why Power over Ethernet is cool

The way it works, PoE eliminates the need for a wall power socket near the end device (PD) itself. And that implies a couple of important things:

  • Flexibility: You can run a network cable to any place, including tight corners. Without the need for an electrical outlet, the end device can stay anywhere, including in outdoor areas.
  • Decluttering: PoE can significantly reduce the number of wires since you won’t need to use a power cord, making it an excellent choice for office devices, such as an IP phone.
  • Savings: You won’t need to spend time (and money) to install electrical wiring and power sockets, which would require a licensed electrician if you want to do it right.

(Again, running network cables generally doesn’t require an electrical license and is reasonably straightforward. Network cables are also relatively affordable; you can find high-end CAT6 in bulk for about $150 per 1000 feet.)

On top of that, PoE is reliable — it’s real wiring, after all. PoE devices are also safe from common power-related issues, such as power surges, overload, or bad wiring. The power injector or the PoE switch would likely take the hit first in case of hazard.

PoE vs. Wi-Fi vs. Powerline

PoE extends a network to one device at a time and cannot replace Wi-Fi. But it can enhance Wi-Fi coverage.

For example, using PoE access points, you can easily extend your Wi-Fi network to an area that doesn’t have a power socket (like the ceiling of a warehouse or the middle of a big yard) without compromising performance.

On the other hand, Powerline is generally the opposite of Power over Ethernet — it’s useful when there are power sockets at a place where network cables can’t reach.

However, PoE is faster and much more reliable in terms of network performance. When you can choose between the two, PoE is the way to go.

Powerline networking: It’s convenient but you can’t always count on it

If you live in a large home, have a large warehouse, or want to place a network device outdoor or at an odd place, PoE comes in handy. It’s a much faster and more affordable solution than installing power cables and receptacles.

How to set up a device with a PoE connection

How to specifically put together a PoE network depends on your devices. However, they all share the same hardware setup process.

A Power over Ethernet Setup
Here’s a typical Power over Ethernet setup (from the bottom up): Router, injector, and a PoE device.

Here are the typical steps you can follow in any order (make sure you don’t mix passive PoE and active PoE devices):

  1. Place the end device (PD) where you want, and connect a network cable to its port. If it has more than one network port, use the port labeled PoE or PoE in.
  2. Plug the other end of the cable directly to a PoE port of the power sender (PSE) — be it a PoE switch or an injector.
  3. Connect the PoE sender to the power and the existing network.

And that’s it. Now the Power over Ethernet end device is part of your network. From the networking point of view, PoE and non-PoE devices are the same. The way they get power doesn’t affect how they function or their performance.

The takeaway

In my book, getting your home wired is always the way to go when it comes to top-notch network performance, even when you want Wi-Fi. And Power over Ethernet makes it even better.

You can use Multi-Gig access points, such as the Netgear WAX630/WAX620, EnGenius EWS850AP, EnGenius ECW230, and a PoE switch to quickly blanket a large property with Wi-Fi 6 without having to worry about electrical wiring or sacrificing performance.

In many ways, Power over Ethernet is networking as seriously as can be.

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20 thoughts on “Power over Ethernet (PoE) Explained: Why It’s Your Wi-Fi’s Best Friend”

  1. Hey Dong!

    Great website. I’ve been combing it regularly as of late. I am upgrading my entire network at home, and this has been very helpful.

    I do have one of those questions I know you probably get tired of answering. Which one? This or that? However, after I explain my situation perhaps there are other opportunities for you to share some valuable information I may be missing. My MAIN question pertains to switches, so I figured I’d ask it here. I could not find an all-inclusive list of how your network switches test and compare to one another, so I’ll just ask.

    What’s the best Unmanaged, Multi-Gig PoE switch for my setup?

    First a little background. I am the proud new owner of a new Starlink kit (FINALLY). I am still awaiting their proprietary “ethernet adapter” to be shipped to me. In the meantime, I am enjoying all kinds of streaming etc. on Wi-Fi only with just their included router/modem and the dish sitting on its stand out in my driveway. Wi-Fi calls on my cell phone have no delay and work great! I do have a Wi-Fi 6E device – Samsung Galaxy S21 Ultra 5G…the first 6GHz device ever if I recall. I easily canceled Viasat since deployment of the Starlink. Now my goal is to do as much as I can with this faster internet and hopefully save some $$ on monthly bills. I have (HAD) Exede (Viasat) at 12 Mbps and $75/mo with a 40GB per month data cap. The hard-wired land line (yes some of us still have to use actual terrestrial phones still HAHA!) is $75/mo. DirecTV is out of sight (over $200/mo.)….especially with NFL Sunday ticket. You can see I can now trim the fat in several places.

    That being said, I am trying to “future-proof” my home as much as possible. I am well aware Starlink is my bottle-neck. So why not keep it that way, and who knows what else will come along in a few years. You’ll see I’m trying to buy stuff that will far outperform Starlink speeds. Of course, this is not JUST for internet speeds. I am very interested in starting to dabble in the IoT world. More importantly than that, one of the very first things I want to add to this home network will be some nice PoE cameras. I would like all my hardware to reflect my goal of future-proofing my network.

    I have been purchasing equipment and hard wiring the house slowly while I wait (and learn).

    I have a brand new Asus ET12 sitting in the box waiting for that ethernet adapter to arrive! I will definitely set them up in a permanent wired backhaul. At each broadcaster location (2) I would like to run immediately into a switch and then out to various devices (main PC (might put this one right into the LAN port on the main router at that location on my desk), 2 TVs, even a DirecTV box for now until I scrap them for cheaper ways to get TV). I will also run another dedicated line to a 3rd room (bedroom) for a TV in there and future expansion via network cables if needed (and a camera or two out that side of the home too). Then the Wi-Fi is just for that…wireless devices, IoT and company visiting.

    I am installing Cat8 shielded EVERYTHING (cable, keystones, etc.). I have yet to order the patch cables from after I make a list of lengths etc.

    Question(s):

    1) Main question: What would be your recommendation for 3 ea. network switches to add to this network?
    Am I correct in assuming all I need is unmanaged PoE switches? I shouldn’t need any additional QoS or anything in addition to what that powerful Asus will do right?
    I only need 4 ports or so per switch. Think the 3 switches are spread around the house equally, like the routers…and I want to run internet devices as well as cameras and even IoT off of them. Can I do this with one switch?
    Is there a way to put the cameras on a separate network (VLAN or whatever)? Is this smart?

    So, my Starlink Speeds can push 200Mbps. But knowing the ET12 tops out at 2.5G, should I just get switches of that caliber, or go higher to future-proof for any reason?

    I think that was most of it. If I’m on the right track, just recommend a great switch. Any additional advice would be gravy.

    Thanks so much.

    Reply
    • I’d go with the Zyxel XS1930-12HP, Coop. I’ve been using it since the review, and it’s excellentβ€”quiet, fast, tons of PoE power. There are not many Multi-Gig switches, and many are prohibitively expensive. I generally buy the hardware for my reviews — if I can’t afford it, chances are most don’t want to buy it.

      The Zyxel XS1930-12HP is a managed switch (most Multi-Gig switches are), but it’s in the unmanaged mode by default. So if you don’t do anything, it works like an unmanaged one.

      Reply
      • Thank you sir! I appreciate the help.

        I still had a question left. Nothing to do with this post now, but is my theory on sharing a switch for my cameras with other IoT or even just my TVs etc. correct? Can I put a PoE camera on one of these switches alongside say a TV and have my cameras all routed to a central recording device, whether it just be my PC running NVR software, or an actual NVR?

        Or do I need to physically separate the hardware of different networks?

        Or, rather, to ask it a different way: Is it adviseable to keep home security cameras on a separate network and hardware set as the rest of the home? And why?

        I’m weeks out from tackling that one. Again, I’m future proofing but also trying to keep it simple. So, if I can do this, as you know I am buying the switches now for the whole-home network, but planning to add PoE cameras later. Am I on the right path?

        Thanks Dong!

        I’ve installed several IP cameras at work, so I know the straightforward method.

        Reply
  2. I am interested in getting a couple of PoE cameras for mobile use, but would like to have only one cable entering the trailer. I have looked at an Outdoor PoE Extender, that extends PoE Power to two PoE devices, but only has one rj-45 input. I would like to have the data come from a router, basically used as a WiFi bridge from another router further from the cameras. So essentially, computer connected to router1; router1 to router2 via WiFi, router2 to PoE sender, sender to extender, extender to cameras (I hope I am explaining this coherently). I don’t readily have access to a 110v outlet to power router2 or the sender, but if necessary, I can run extension cord, but would prefer powering from a 12v source. I would appreciate your thoughts on this, and possibly a couple of sources for 12v powered devices.

    Reply
  3. Which would be the best buy ASUS AX XT8 for Wifi 6 or Wifi 6E?
    Can I used a PoE Cat 6 cable between units to facilitate 2nd unit?

    Reply
  4. Happy New Year Dong!

    Just got Starlink Beta and the PoE powers the dish and the router which is a very cool setup. However I have doubts the supplier router will be sufficient for the entire house. I would like to plug in my old router and based on my understanding I should be good to go, my old router will not ask for power so there should be no sparks or smoke…do you agree?

    Reply
    • I don’t know what your old router is, Daniel. So check the post again regarding the PoE standard. Generally, you don’t want to use a passive PoE injector with a standard PoE device.

      Reply
  5. You mention PoE range of about 300 ft. If my Cat5e run is approaching this (about 250ft) and there is at least 1 maybe 2 or 3 couplers in-between (not including patch panel, keystone jacks, etc.) extending the cable run, do you think the PoE device will not function as intended? (PoE wireless access point)
    Trying to decide whether to get a PoE unmanaged switch or save some money and get a basic unmanaged switch πŸ™‚

    Reply
  6. When connecting from the PoE power source device and the receiver, is it OK to use cat6 wire to go from a patch panel at the router to an RJ-45 jack for the receiver? I want to connect the camera and the PoE power source with short cables into the jack and the patch panel. Stated another way, do patch panels and RJ-45 jacks maintain the power from source to receiving device?

    Reply
    • Yes, Richard. You can think of the patch panel, this case, as stitching two short cables into a long one. I’ll work fine.

      Reply

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