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PoE vs non-PoE switches: which do you need?

How Power over Ethernet works, PoE standards and budgets, and when a PoE switch is the right choice for cameras, access points and IP phones.

Published
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2 min
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USTS Oman

What PoE does

Power over Ethernet (PoE) sends electrical power and data over the same network cable. Devices such as IP cameras, Wi-Fi access points, IP phones and some access-control readers can run without a separate power adapter at their location.

PoE standards

Devices and switches must support a compatible standard. The common IEEE standards are:

  • 802.3af (PoE): up to 15.4 W per port at the switch
  • 802.3at (PoE+): up to 30 W per port
  • 802.3bt (PoE++ Type 3 / Type 4): up to 60 W / 90 W per port
POE SWITCHshared PoE budgetIP PHONE802.3af · ≤ 15.4 WACCESS POINT802.3at · ≤ 30 WPTZ CAMERA802.3bt · ≤ 60 / 90 Wmax 100 m per run
Fig. 1 — One cable carries data and power. Budget is per port and for the whole switch; each run is limited to 100 m.

Check the total PoE budget

A switch’s total PoE budget is often lower than its port count multiplied by the maximum per port. Add up the real consumption of every powered device — PTZ cameras and cameras with heaters or strong IR draw more — and leave headroom.

When a non-PoE switch is fine

Computers, printers, servers and devices with their own power supply do not need PoE. Many networks use PoE switches at the edge for cameras and access points and non-PoE switches for workstations.

Managed or unmanaged?

Managed switches allow VLANs, monitoring and remote power-cycling of a device that has stopped responding. For business networks carrying CCTV, voice and guest Wi-Fi, managed switching is usually worth it.

Cable distance

Standard Ethernet, including PoE, is specified up to 100 metres per cable run. Longer runs need an intermediate switch, a PoE extender or fibre.

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