If you need to power a device over Ethernet, you have two main options — a PoE injector or a PoE switch. Which you need depends on how many devices you’re powering and what your existing network looks like. Getting this choice wrong doesn’t break anything, but it can mean spending more than you need to, or buying a single injector and then replacing it with a switch six months later when you’ve added more devices.
What Is a PoE Injector?
A PoE injector sits inline between your existing switch and a PoE-powered device. You plug a standard Ethernet cable from your switch into the injector’s uplink port, then run a second cable from the injector’s PoE output port to your device. The injector draws power from a standard mains socket and combines it onto the Ethernet cable.
Most injectors available today support active PoE standards — 802.3af (15.4W), 802.3at (30W), or 802.3bt (60W/90W) — and will negotiate with the connected device before delivering power. Single-port injectors are the most common, though multi-port injector panels do exist. For a full breakdown of how they work, see our guide on what is a PoE injector.
What Is a PoE Switch?
A PoE switch is a network switch with PoE built into some or all of its ports. Rather than adding power externally, the switch delivers data and power through the same ports simultaneously. You connect your PoE devices directly to the switch — no inline injector required.
PoE switches come in two broad categories:
Unmanaged PoE Switches
Plug-and-play, no configuration required. You power them on and they work. Good for straightforward deployments where you don’t need per-port control or VLANs. Budget 8-port unmanaged PoE switches start around £60–£80 in the UK.
Managed PoE Switches
Offer per-port power control, PoE scheduling, power monitoring, VLAN support, SNMP, and more. These are what you’d use in a proper rack or enterprise deployment. Managed PoE switches from brands like Netgear, TP-Link, and Cisco start around £120–£150 for 8 ports and go significantly higher for 24-port or 48-port models.
Every PoE switch has a total PoE power budget — the maximum wattage it can deliver across all PoE ports simultaneously. A typical 8-port unmanaged PoE switch might have a 65W or 78W budget. If you fill all 8 ports with 802.3af devices drawing 15.4W each, that’s 123W — you’d exceed the budget and the switch would either throttle ports or refuse to power some devices. Always check the PoE budget before buying.
Side-by-Side Comparison
| Factor | PoE Injector | PoE Switch |
|---|---|---|
| Cost | £15–£40 per port | £60–£200+ (covers multiple ports) |
| Number of devices | Best for 1–3 devices | Efficient from 4+ devices |
| Existing switch needed | Yes — injector has no switching | No — replaces your switch |
| Cable runs | Requires two cable segments at injector location | Single run from switch to device |
| Management | None (mostly) | Full per-port control on managed models |
| Failure point | One injector per device — isolated failure | Switch failure affects all connected devices |
| Best for | Adding PoE to an existing setup | New installations, rack builds, multi-device setups |
When to Choose a PoE Injector
A PoE injector is the right call in the following situations:
You only need to power one to three devices. If you’re adding a single wireless access point to an existing wired network, buying an entire PoE switch to replace a functioning non-PoE switch makes no sense. A single-port injector at £15–£25 does the job cleanly.
You already have a good non-PoE switch. Many IT professionals have a solid unmanaged or managed switch already in place. Replacing it with a PoE switch just to power one AP wastes both money and effort. An injector lets you keep your existing switch and layer PoE on top.
You’re on a tight budget. An 8-port PoE switch for three devices means paying for five ports you’re not using. Three injectors might cost less and give you exactly what you need.
Temporary or field installations. Injectors are compact and simple to deploy in temporary setups — on-site events, temporary security camera positions, or testing environments.
Outdoor or remote single-device installs. If you’re running a single cable to an outdoor AP or IP camera at the end of a long cable run, an injector placed at the switch end is the standard approach.
A classic example: you’re adding a single Ubiquiti UniFi access point to a home office or small business network. You have a good 8-port unmanaged switch already. One PoE injector, £20, job done.
When to Choose a PoE Switch
A PoE switch becomes the better choice as soon as the scale tips:
Four or more PoE devices. At this point, the cost per port of individual injectors starts to exceed that of a dedicated PoE switch, and cable management becomes messy. A single switch is cleaner and more cost-effective.
New installation from scratch. If you’re cabling a new office, server room, or home lab, spec in a PoE switch from the start. There’s no reason to buy a non-PoE switch and then add injectors later.
Rack-mounted setup. Individual injectors don’t rack-mount neatly. A 1U or 2U rack switch with PoE keeps everything tidy and manageable.
Per-port power monitoring. Managed PoE switches let you see how much power each port is drawing, disable ports remotely, and set power limits. This is useful in installations where you need to track device uptime or troubleshoot remotely.
VLAN support and advanced switching features. If you need to segment your network — for example, putting IP cameras on an isolated VLAN or separating guest Wi-Fi from your main LAN — you need a managed switch anyway. Adding PoE to that switch is a natural step.
Can You Use Both?
Yes, and it’s more common than you’d think. Plugging a PoE injector into a PoE switch port is electrically fine — the switch and injector will both attempt to negotiate with the connected device, but the device will only draw power from one source. In practice, if you plug an injector’s uplink into a PoE switch port, the switch may detect the injector as a non-PoE device and simply pass data through without delivering power to that port. The injector then powers the downstream device. It works, but it’s redundant — you’re paying for PoE capability on the switch port and not using it.
Where mixing does make sense is in larger, mixed installations. You might have a core 24-port PoE switch in your server room powering most of your access points, plus a single PoE injector in a remote cabinet at the far end of the building where adding a secondary switch would be overkill. That’s a perfectly reasonable architecture.
Budget Considerations
Here’s a rough guide to current UK pricing (2025–2026):
- Single-port passive PoE injector: £8–£15. Generally for specific low-voltage applications — be careful about compatibility.
- Single-port active PoE injector (802.3af): £15–£25. The standard choice for one AP or camera.
- Single-port active PoE injector (802.3at): £20–£40. Needed for higher-draw devices like PTZ cameras or 802.3at access points.
- 8-port unmanaged PoE switch: £60–£120. Varies considerably by PoE budget and brand.
- 8-port managed PoE switch: £120–£200. Adds VLAN, SNMP, per-port control.
- 24-port managed PoE switch: £200–£600+. Significant range depending on PoE budget, uplink speed, and brand.
As a rough rule: if the cost of individual injectors for your planned device count approaches 60–70% of a basic PoE switch, just buy the switch.
The Ubiquiti and DrayTek Question
A significant portion of UK small business and home lab installs use Ubiquiti UniFi access points or DrayTek VigorAPs. Both product lines commonly ship without a power supply or PoE injector in the box — they assume you already have a PoE switch or will buy an injector separately.
For a single UniFi AP in a location where you have an existing non-PoE switch, a single-port injector is the standard solution. If you’re deploying three or more UniFi APs in a business environment, a UniFi-compatible PoE switch (or Ubiquiti’s own UniFi switches) makes more sense. For a detailed walkthrough of powering a specific Ubiquiti AP, see our guide on how to power a Ubiquiti access point using a PoE injector.
DrayTek VigorAPs generally support standard 802.3af PoE, so any compliant active injector or PoE switch port will work without issues.
Making the Decision
The short version: start with an injector if you have one or two devices to power and an existing switch worth keeping. Move to a PoE switch if you’re installing four or more PoE devices, starting fresh, or need proper network management. If you’re unsure, lean toward the PoE switch — it’s easier to grow into than to replace a collection of injectors later.
Related: best UniFi access point for home
