Complete Guide to PoE and PoE+: Powering Your Network Equipment via Ethernet

Tired of running electrical cables everywhere to power your IP cameras and Wi-Fi access points? Good news: Power over Ethernet (PoE) will simplify your life! This technology, which has been around for over 20 years, allows you to transmit both data AND power through a single Ethernet cable. Pretty convenient, right? Discover how it works and, more importantly, how to save big with used professional equipment from major brands.

What exactly is PoE?

Imagine this: you install a security camera at the back of your warehouse. With a traditional setup, you need a network cable for the data AND a nearby power outlet (hello electrician's work at €80/hour minimum!). With PoE, a single Ethernet cable does all the work.

The principle? Your network switch sends electrical current through the unused wire pairs of the Ethernet cable. Your PoE-enabled devices receive both their network connection and power through this same cable. Simple, elegant, and economical. This is why virtually all modern IP cameras and professional Wi-Fi access points are PoE-compatible today.

PoE, PoE+ or PoE++: Which one do you really need?

PoE Standard (802.3af): The basics

This is the "little brother" of the family, launched in 2003. It delivers up to 15.4 watts per port. That might seem low, but it's more than enough for a basic IP phone, a small fixed surveillance camera, or connected sensors. To give you an idea, your smartphone typically charges with 10-20W.

PoE+ (802.3at): The sweet spot

This is my favorite! Released in 2009, it doubles the power with 30 watts per port. That's exactly what's needed to power demanding equipment: PTZ cameras that move around a lot, high-performance WiFi access points with multiple antennas, HD video phones... In my experience, 80% of professional installations are perfectly happy with PoE+, without needing to upgrade.

PoE++ (802.3bt): Maximum power

Now we're talking serious power with up to 100W per port. Honestly? Unless you're powering LED screens, mini-computers, or ultra-comprehensive video conferencing systems, you'll probably never need it. And the price reflects that! I advise you to carefully assess your actual needs before investing in PoE++.

Where PoE truly shines: Practical applications

Video surveillance: Goodbye to electrical outlets!

This is THE ultimate PoE application. I've seen installations of 50+ IP cameras completed in just a few days thanks to PoE, where a traditional installation would have required three weeks of electrical work. Need a camera above your front door? A simple Ethernet cable from your utility room and you're good to go. Moving a camera? You unplug it, plug it in elsewhere. No electrician, no hassle.

And if you opt for used PoE+ switches (HP, Cisco, TP-Link, etc.), you can easily reduce your budget by a factor of three or four. I have clients who equipped their small businesses with used HP ProCurve professional equipment for the price of new, low-end Chinese switches!

WiFi everywhere, without restrictions

Want optimal WiFi coverage? You need to place your access points high up, ideally on the ceiling. Problem: how do you power them up there? With PoE, that's solved. I've personally installed dozens of access points in historic buildings where running electrical wiring was impossible. PoE saved those projects!

IP telephony: Total flexibility

One of my clients recently completely reorganized his offices. With PoE IP phones, it took him a morning. Everyone unplugged their phone, took it to their new desk, and plugged it back in. That's it! No electrician to call, no construction work, no service interruption. A dream come true.

PoE budgeting: How to avoid unpleasant surprises

Ah, the infamous PoE budget! It's the trap that 70% of people fall into when buying their first PoE switch. So buckle up, I'm going to explain it simply.

You see a 24-port PoE+ switch that displays "30W per port." You think, "Great, I can plug in 24 devices that each consume 30W!" Wrong! This switch has a total PoE budget, let's say 370W. This means that the sum of all your devices must not exceed 370W. Not the theoretical 720W (24 x 30W).

The simple method for calculating

1. List all your PoE devices : 10 cameras that consume 8W each, 5 WiFi access points at 15W...
2. Add it up : (10 × 8W) + (5 × 15W) = 155W
3. Add a 20-25% margin : 155W × 1.25 = 194W minimum required
4. Choose a switch with more power : Opt for a model with a 250W or 370W budget.

My personal advice : Always budget generously for PoE. It costs only slightly more (especially used equipment), and you'll have peace of mind when upgrading your setup. I've seen too many people struggle because they budgeted too little!

And here's the killer tip: a used HP ProCurve switch with a 370W PoE power budget often costs less than €200, while the same one new would cost over €800. It's exactly the same hardware, tested and working, removed from a professional environment. See the savings?

Why PoE will save you money

Installation: Cut your costs by at least half

Let's be honest: an electrician will easily charge you €80-120 per hour. Running an electrical line and installing a socket takes 1 to 2 hours of work, depending on the location. Multiply that by 15 IP cameras... and you quickly reach several thousand euros in electrical work.

With PoE? Your network installer runs an Ethernet cable, plugs it into the switch, and that's it. Cost: 30 minutes max per connection point. I have customer feedback showing savings of 40 to 60% on total installation costs. That's huge!

Flexibility: Move your equipment without stress

Want to move a camera? With a traditional electrical installation, you either have to run a new line (expensive) or make do with existing locations (frustrating). With PoE, you just run a new Ethernet cable (€15 for 100m of Cat6) and that's it. Your intern could do it!

Centralized UPS: Service continuity

A small bonus that's often overlooked: by powering all your equipment through your PoE switches, you can connect those switches to a centralized UPS. Power outage? Everything keeps working (cameras, Wi-Fi, phones) for hours. Try doing that with 30 power supplies scattered throughout the building... Good luck!

How to choose your PoE switch (without making a mistake)

The number of ports: Think big!

If you need 15 ports today, get a 24-port switch. Why? Because in six months, you'll want to add three more cameras, upgrade your Wi-Fi, install an access control system... And then you'll be glad you had the extra capacity. Used 24-port switches only cost €50 more than a 16-port one, so honestly, don't bother.

PoE budget: We've already talked about this, but it's crucial

Don't just look at the number of ports! A 24-port switch with a 180W PoE budget is useless if you have 20 devices that each consume 12W (requiring 240W). ALWAYS check the total budget before buying.

Manageable or not? My clear position

For 5-8 PoE devices in an office, an unmanaged switch will suffice. Beyond that, definitely get a managed switch. Being able to monitor the PoE power consumption of each port, remotely restart a malfunctioning camera, create VLANs to separate your cameras from your office network... it's invaluable. And on the used market, the price difference is negligible (only €30-50 more).

Gigabit Ethernet required (even in 2025)

Don't bother getting Fast Ethernet (10/100 Mbps) just because it's "cheaper." A 4K camera will saturate a 100 Mbps connection. So will a Wi-Fi 6 access point. Get Gigabit (10/100/1000), period. Besides, you can hardly find anything but Gigabit on the used market these days.

The opportunity: Why pay full price?

Where exactly did this material come from?

A legitimate question! The switches we offer come from companies renewing their infrastructure, data centers upgrading, companies closing a site... In short, equipment retired while still working perfectly. It's "business surplus," not defective equipment.

I've even seen batches from major CAC40 companies that were changing their fleets every 5 years purely for internal reasons, even though the equipment was in perfect condition. Their "old" stuff becomes your bargain!

Mind-blowing savings (really)

An HP ProCurve 2530-24G-PoE+ switch (24 Gigabit ports, 195W PoE budget, managed) costs over €800 new. A used one I've tested? Between €150 and €250 depending on its cosmetic condition. It's exactly the same switch, with the same performance and reliability. The only difference? A few scratches on the casing and a sticker from the previous owner.

With the savings they made, some of my clients were able to buy high-end equipment (HP, Cisco) instead of settling for cheap Chinese stuff. The result: better quality AND lower prices. A winning combination!

These switches don't age (or hardly at all).

Here's something many people don't know: a professional switch is designed to operate continuously, 24/7, for 10-15 years. The components are rated for millions of hours of service (MTBF > 100,000 hours). A 5-year-old switch isn't even halfway through its lifespan!

I still have HP and Cisco switches from 2010 in service that run like clockwork. Not a single failure. These things are indestructible. So yes, buying a used 3-5 year old professional switch is simply good economic sense.

Tested = Reliable

Every used switch we offer undergoes a series of tests: all PoE ports are individually checked, the total PoE budget is validated, throughput is measured, and the firmware is updated if necessary. We only sell 100% functional equipment. Defective switches are recycled, period.

And the planet thanks you.

Okay, let's be honest: you buy used mainly to save money. But the environmental benefit is very real! Producing a new switch requires mining (copper, gold, rare earth elements), manufacturing in Asia with its carbon footprint, international shipping... Reusing an existing switch avoids all of that. That's the circular economy for you.

Installation: It's really simple

Plug it in, it's ready (or almost)

1. Find a well-ventilated location : Your switch gets a little warm (especially with PoE). Place it in a rack, a server room, or at least avoid enclosing it in a closed cabinet.
2. Connect the power supply : Ideally to a UPS, but a surge-protected power strip will do.
3. Connect it to your network : An Ethernet cable from your modem/router to the switch
4. Connect your PoE devices : Cameras, WiFi, phones... All to the switch ports
5. Check the LEDs : If they flash green/orange, it's good!

Honestly, even if you're not tech-savvy, you can do this yourself in 30 minutes. I've seen restaurant owners, mechanics, and real estate agents install their PoE switches without any problems.

Configuration (for managed switches)

That's a step above. But rest assured, modern interfaces are quite intuitive. You type the switch's IP address into your browser, log in with the default credentials (often admin/admin), and access a web interface.

The basic settings to make: update the firmware (important for security), create VLANs if you want to separate your cameras from your office network, configure email alerts if a PoE port is saturated... If you are not comfortable, any freelance IT technician will do this for €50-100.

Cables and distances: What you need to know

What type of cable?

PoE works with standard Ethernet cables. But pay attention to the type:

• Cat5e : OK for PoE/PoE+ up to 100m. The bare minimum.
• Cat6 : Better, more reliable, a little more expensive. My default choice
• Cat6a/Cat7 : If you're using PoE++ or want peace of mind for 20 years

My advice? Use shielded Cat6 (STP) cable for outdoor installations or those near electrical sources. For indoor use, unshielded Cat6 (UTP) is perfectly adequate.

The 100-meter limit (must be respected!)

This is THE golden rule of Ethernet: a maximum of 100 meters between the switch and the device. Beyond that, the signal degrades and the PoE power drops. I've seen installations where cameras wouldn't even turn on after 120 meters... Don't cheat this limit!

If you really need to go further, there are solutions: PoE extenders (which regenerate the signal), intermediate switches, or switching to fiber optics with a local PoE switch at the end.

Good news: Backward compatibility works

Do you have a PoE+ switch but only standard PoE devices? No problem, it works! The switch automatically detects what the device needs and adjusts the power accordingly. It's intelligent; it's called "PoE negotiation."

However, if you connect a PoE+ device (which requires 30W) to a standard PoE switch (15W max), the device will either operate in a degraded mode or fail to start. Makes sense!

Some brands worth considering

TP-Link: Unbeatable value for money

For small installations (8-16 ports), TP-Link makes excellent equipment at affordable prices. Their "Easy Smart" models are perfect for getting started with basic management. I've deployed dozens of them and never had a problem. And you can find them used for next to nothing.

HP (ProCurve/Aruba): The Rolls of the switch

My favorites! HP ProCurve switches are indestructible, their management interface is simple, and they have generous PoE budgets. I have 15-year-old HP switches that are still running perfectly. Plus, HP offered a lifetime warranty on many models. Buying used is the best deal.

Cisco: For the purists

Cisco is the Porsche of networking. Extremely reliable, extremely high-performing, but also extremely expensive (even used). If you have a large infrastructure or very specific needs, go for it. Otherwise, HP or Netgear will do just fine.

Netgear and Zyxel: Reliable choices

These two are positioned between TP-Link and HP. Good performance, comprehensive features, reasonable prices. Netgear is particularly appreciated for its switches with high PoE power outputs (up to 380-400W on some 24-port models).

Take a look at our selection of used PoE switches from all these brands. You'll be surprised by the prices!

In summary: Why PoE is a game changer

After 10 years of installing and troubleshooting networks, I can tell you: PoE is one of the best inventions in the IT world. It simplifies everything, saves thousands of euros on installations, and offers incredible flexibility.

And when you combine that with second-hand equipment from major brands, you have the perfect combo: professional quality + low price + eco-friendly choice. What more could you want?

Whether you're installing five IP cameras in your business, deploying a Wi-Fi network in your offices, or switching to IP telephony, PoE will make your life easier. And with tested, pre-owned switches sourced from professional environments, you take no risks.

Carefully calculate your PoE budget (this is truly the crucial point), allow a little extra for the future, and you'll be set for years to come. Your network will thank you!