Complete PoE and PoE+ Guide: Power Your Network Equipment via Ethernet

Tired of running electrical cables everywhere to power your IP cameras and WiFi access points? Good news: Power over Ethernet (PoE) will make your life easier! This technology, which has existed for over 20 years now, allows both data AND electricity to pass through a single Ethernet cable. Pretty handy, right? Discover how it works and especially how to save big with professional-grade used equipment from top brands.

What Exactly Is PoE?

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

The principle? Your network switch sends electrical current through the unused wire pairs in the Ethernet cable. Your PoE-compatible devices receive both their network connection and power through the same cable. Simple, elegant, economical. That’s why almost all modern IP cameras and professional WiFi access points are PoE-compatible today.

PoE, PoE+, or PoE++: Which One Do You Really Need?

Standard PoE (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 usually charges with 10-20W.

PoE+ (802.3at): The Sweet Spot

Here’s my favorite! Released in 2009, it doubles the power with 30 watts per port. It’s just right for powering demanding equipment: PTZ cameras that move in all directions, high-performance WiFi access points with multiple antennas, HD video phones... From experience, 80% of professional installations are perfectly fine with PoE+ and don’t need to step up to the next level.

PoE++ (802.3bt): Maximum Power

Here, we’re entering the big leagues with up to 100W per port. Honestly? Unless you’re powering LED screens, mini-computers, or ultra-complete video conferencing systems, you probably won’t ever need this. And the price reflects that! I recommend carefully assessing your real needs before investing in PoE++.

Where PoE really shines: Practical applications

Video surveillance: Goodbye electrical outlets!

This is THE ultimate PoE application. I’ve seen installations of 50+ IP cameras done in 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? Just an Ethernet cable from your technical room and off you go. Moving a camera? Unplug it, plug it in elsewhere. Zero electrician, zero hassle.

And if you choose used PoE+ switches (HP, Cisco, TP-Link...), you can easily divide your budget by 3 or 4. I have clients who equipped their SMEs with used professional HP ProCurve gear for the price of low-end new Chinese switches!

WiFi everywhere, without constraints

Want optimal WiFi coverage? You need to place your access points high up, ideally on the ceiling. Problem: how to power them up there? With PoE, it’s solved. I personally installed dozens of access points in historic buildings where running electrical power 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 needed, no work, no service interruption. A dream.

The PoE budget: How to avoid unpleasant surprises

Ah, the famous PoE budget! It’s the trap where 70% of people buying their first PoE switch fall. So hang on, I’ll explain it simply.

You see a 24-port PoE+ switch that says "30W per port." You think: "Great, I can connect 24 devices each consuming 30W!" Wrong! This switch has a total PoE budget, say 370W. That means the sum of all your devices must not exceed 370W. Not the theoretical 720W (24 × 30W).

The simple method to calculate

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

Faster: instead of calculating by hand, use our free PoE budget calculator — enter your devices and switch budget, and it immediately gives you the total and remaining margin.

My personal advice: Always go big on your PoE budget. It costs barely more (especially used), and you’ll have peace of mind to upgrade your setup. I’ve seen too many people struggle because they went with the bare minimum budget!

And here’s the killer tip: a used HP ProCurve switch with a 370W PoE budget often costs less than €200, while the same new one was over €800. It’s exactly the same equipment, 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 talk money: an electrician easily charges €80-120 per hour. Running an electrical line and installing an outlet takes 1 to 2 hours depending on the location. Multiply that by 15 IP cameras... 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: max 30 minutes per point. I have client feedback showing 40 to 60% savings on total installation costs. That’s huge!

Flexibility: Move Your Equipment Stress-Free

Want to move a camera? With a traditional electrical setup, you either have to run a new line (expensive) or settle for existing locations (frustrating). With PoE, you just run a new Ethernet cable (€15 per 100m in Cat6) and that’s it. Your intern can do it!

Centralized UPS: Service Continuity

A little bonus we don’t always think about: by powering all your devices through your PoE switches, you can connect these switches to a centralized UPS. Power outage? Everything keeps running (cameras, WiFi, phones) for hours. Try doing that with 30 separate power supplies scattered around the building... Good luck!

How to Choose Your PoE Switch (Without Making Mistakes)

Number of ports: Think big!

If you need 15 ports today, get a 24-port switch. Why? Because in 6 months, you’ll want to add 3 more cameras, upgrade your WiFi, install an access control system... And you’ll be glad to have the extra capacity. Used 24-port switches cost only €50 more than 16-port ones, so honestly, don’t bother.

PoE budget: We’ve talked about it, but it’s crucial

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

Manageable or not? My clear stance

For 5-8 PoE devices in an office, an unmanaged switch will do. Beyond that, get a manageable switch, seriously. Being able to monitor PoE consumption per port, remotely reboot a frozen camera, create VLANs to separate your cameras from your office network... Priceless. And used, the price difference is minimal (€30-50 more).

Gigabit mandatory (even in 2025)

Don’t bother with Fast Ethernet (10/100 Mbps) just because “it’s cheaper.” A 4K camera will saturate a 100 Mbps connection. A WiFi 6 access point too. Get Gigabit (10/100/1000), period. Anyway, used gear is almost exclusively Gigabit now.

Used gear: Why pay full price?

Where exactly does this equipment come from?

Legitimate question! The switches we offer come from companies renewing their infrastructure, data centers upgrading, companies closing sites... In short, equipment removed while still working perfectly. It’s “professional surplus,” not defective gear.

I’ve even seen batches from major CAC40 companies that replaced their equipment every 5 years purely due to internal policy, even though the gear was in perfect condition. Their “old” gear becomes your bargain!

Incredible savings (really)

An HP ProCurve 2530-24G-PoE+ switch (24 Gigabit ports, 195W PoE budget, manageable) costs over €800 new. Tested used? Between €150 and €250 depending on cosmetic condition. It’s exactly the same switch, with the same performance and reliability. The only difference? A few scratches on the case and a label from the previous company.

With the savings, some of my clients were able to afford high-end gear (HP, Cisco) instead of settling for low-end Chinese products. Result: better quality AND lower price. The winning combo!

These switches don’t really age (or barely)

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

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

Tested = Reliable

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

And the planet thanks you

Let’s be honest: you buy used mainly to save money. But the ecological bonus is real! Producing a new switch requires mining (copper, gold, rare earths), manufacturing in Asia with its carbon footprint, international shipping... Reusing an existing switch avoids all that. Circular economy, basically.

Installation: It’s really simple

Plug it in, it’s ready (or almost)

1. Find a ventilated spot: Your switch heats up a bit (especially with PoE). Put it in a rack, a technical room, or at least avoid enclosing it in a closed cabinet
2. Plug in the power: Ideally on a UPS, but a surge protector power strip will do
3. Connect it to your network: An Ethernet cable from your box/router to the switch
4. Connect your PoE devices: Cameras, WiFi, phones... All on the switch ports
5. Check the LEDs: If they blink green/orange, you're 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 switch without any problem.

Configuration (for manageable switches)

This is a step up. But don’t worry, modern interfaces are quite intuitive. You type the switch’s IP address into your browser, log in with default credentials (often admin/admin), and access a web interface.

Basic settings to do: 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 saturates... If you’re not comfortable, any freelance IT specialist can do this for €50-100.

Cables and distances: What you need to remember

What type of cable?

PoE works with standard Ethernet cables. But watch the category:

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

My advice? Use shielded Cat6 (STP) for outdoor installations or near electrical sources. For indoors, unshielded Cat6 (UTP) is more than enough.

The 100-meter limit (must be respected!)

This is THE golden rule of Ethernet: maximum 100 meters between the switch and the device. Beyond that, the signal degrades and PoE power drops. I’ve seen setups where cameras at 120m wouldn’t even turn on... 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 optic 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. It’s smart, it’s called “PoE negotiation.”

However, if you connect a PoE+ device (which needs 30W) to a standard PoE switch (15W max), either the device runs in degraded mode, or it won’t start. Makes sense!

Some brands worth considering

TP-Link: The unbeatable value for money

For small setups (8-16 ports), TP-Link makes very good equipment at affordable prices. The "Easy Smart" models are perfect for starting with basic management. I've deployed dozens, never had a problem. And second-hand, you can find them for a bargain.

HP (ProCurve/Aruba): The Rolls-Royce of switches

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 still running without a hitch. Plus, HP offered a lifetime warranty on many models. Used, it's THE good deal.

Cisco: For the purists

Cisco is the Porsche of networking. Super reliable, high performance, but also very 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: The reliable choices

These two sit between TP-Link and HP. Good performance, full features, reasonable prices. Netgear is especially appreciated for its switches with large PoE budgets (up to 380-400W on some 24-port models).

Go check out our HP / ProCurve / Aruba switches, our Cisco switches, and our entire selection of used switches from all these brands. You'll be surprised by the prices!

In summary: Why PoE is a game changer

After 10 years 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 used equipment from major brands, you get the perfect combo: professional quality + low price + eco-friendly choice. What more could you want?

Whether you're installing 5 IP cameras in your store, deploying a WiFi network in your offices, or switching to IP telephony, PoE will make your life easier. And with tested used switches from professional environments, you take no risk.

Carefully calculate your PoE budget (this is really the crucial point), leave a small margin for the future, and you'll be set for years. Your network will thank you!