Power over Ethernet (PoE) is one of the most useful networking technologies you may have never thought about. It lets a single Ethernet cable carry both data AND electrical power to a remote device — eliminating the need for a separate power outlet wherever you want to install equipment.
If you've ever installed an IP security camera, a VoIP phone, a wireless access point, or a smart doorbell that "just works" with one cable, you've used PoE. As edge computing and IoT expand in 2026, PoE has become the standard way to deploy networking devices across buildings, campuses, and outdoor environments.
How PoE works
A PoE-capable network switch (the Power Sourcing Equipment or PSE) injects DC power onto the Ethernet cable along with the data signals. At the other end, the Powered Device (PD) — your camera, phone, or access point — extracts the power from the cable and uses it to operate.
The clever part: standard Ethernet uses only 4 of the 8 wires in a Cat5e/Cat6 cable for 10/100 Mbps data. The remaining 4 wires are available to carry power. For Gigabit Ethernet (which uses all 8 wires for data), PoE injects power as a common-mode signal that doesn't interfere with the data.
Before sending power, the PSE performs a classification handshake — it checks that the connected device actually wants power (so it doesn't fry a non-PoE laptop), then negotiates how much power to supply.
PoE standards and wattage levels
There are three main PoE standards, each delivering progressively more power:
PoE (IEEE 802.3af) — Up to 15.4W at the source, 12.95W at the device — The original 2003 standard. Sufficient for VoIP phones, basic IP cameras, low-power wireless access points, and simple sensors. Most Cat5e cabling installed in the 2000s supports 802.3af PoE.
PoE+ (IEEE 802.3at) — Up to 30W at the source, 25.5W at the device — Released in 2009. Supports more demanding devices: PTZ (pan-tilt-zoom) cameras with heaters, mid-range wireless access points, video phones with displays, and small thin clients. Cat5e is sufficient for short runs; Cat6 recommended for longer runs.
PoE++ Type 3 (IEEE 802.3bt) — Up to 60W at the source, 51W at the device — Released in 2018. Supports high-power access points (Wi-Fi 6/6E with multiple radios), advanced video phones, and small computing devices.
PoE++ Type 4 (IEEE 802.3bt) — Up to 100W at the source, 71.3W at the device — The highest standard PoE level. Powers laptops, displays, building management systems, LED lighting, and sophisticated edge computing devices. This is where PoE starts to compete with traditional AC power for many endpoints.
There's also a non-standard category sometimes called "PoH" or "UPOE+" delivering up to 90W on cable that some vendors offer, but for compatibility, stick to the IEEE standards.
What cable do you need for PoE?
Here's where cable selection matters enormously. Higher PoE power levels generate more heat in the cable, and that heat affects what cable you need.
For PoE (15.4W): Cat5e is acceptable. Quality matters less because the power is low.
For PoE+ (30W): Cat5e works for runs under 80m. Cat6 is recommended for longer runs or bundled cable installations.
For PoE++ Type 3 (60W): Cat6 minimum. Cat6a strongly recommended for any installation with multiple cables bundled together. The thicker conductors in Cat6/Cat6a (typically 23 AWG vs Cat5e's 24 AWG) reduce voltage drop and heat buildup.
For PoE++ Type 4 (100W): Cat6a or higher is essentially required. The current draw at 100W is enough that thinner cables (Cat5e) can experience excessive voltage drop and overheating, especially in cable bundles. Cat6a's tighter twist rates and better shielding handle the heat much better.
Solid copper conductors only. This is critical and often overlooked. Copper-clad aluminum (CCA) cable — sometimes sold cheaply as "Ethernet cable" — has higher resistance than solid copper. With PoE, that extra resistance creates excessive voltage drop and dangerous heat. CCA is unsafe for PoE and not compliant with TIA/EIA standards. Always verify your cable is solid copper.
Common PoE-powered devices
IP security cameras — The single most common PoE application. Indoor cameras typically use PoE (15W), while outdoor cameras with heaters and PTZ use PoE+ (30W) or higher.
Wireless access points — Wi-Fi 6 and Wi-Fi 6E APs need 30-60W depending on the model. Wi-Fi 7 APs can require up to 100W (PoE++ Type 4).
VoIP phones — Standard desk phones run on basic PoE. Phones with large displays or sidecars may need PoE+.
Video doorbells and intercoms — Most modern smart doorbells run on PoE.
Building access controllers — Card readers, electric door strikes, and access control panels.
Digital signage — Small LCD displays for menu boards, wayfinding, and information kiosks.
LED lighting — Newer commercial LED systems support PoE for both power and control.
Edge computing devices — Industrial PCs, IoT gateways, and small servers in distributed deployments.
Practical tips for PoE installations
Plan for 30% power headroom. A 100W device on a 100W PoE port has zero margin. Use a switch with at least 130W per port if you're running maximum-load devices.
Check the PSE budget. A 24-port PoE switch might advertise "PoE+ on all ports" but only have a total power budget of 370W — that's only 15W per port if all 24 are loaded. Read the spec sheet for the total PoE budget, not just the per-port maximum.
Consider voltage drop on long runs. PoE+ at 100m might deliver less power than at 30m. For critical devices at the cable maximum (100m), use Cat6a and verify the device receives sufficient voltage.
Don't chain PoE through unmanaged switches. Some unmanaged switches don't pass PoE. Connect PoE devices directly to the PoE switch port whenever possible.
Surge protection matters outdoors. Outdoor PoE cameras should connect through PoE-rated surge protectors at both ends to protect from lightning and power surges.
At Kentek, all our Cat6 and Cat6a Ethernet cables use solid copper conductors and are PoE-safe through PoE++ Type 4 (100W). We carry patch cables in 9 colors for clean PoE deployments and bulk Cat6 in 1000ft for in-wall PoE installations.