Power over Ethernet started as 15 W of bench juice for VoIP phones. Today, Type 4 PoE delivers 90 W, enough to run a video conferencing system or PoE-powered LED lighting. Pick the type wrong and your access point reboots under load.
Four ideas to carry into the next specification conversation you have.
Type 1 = 802.3af (2003). Type 2 = 802.3at (2009). Types 3 & 4 = 802.3bt (2018). Each adds power, both via better pair use and higher current.
PSE = switch / injector (source). PD = powered device. Cable losses mean Type 4 delivers 90 W at PSE, 71 W minimum at PD over 100 m Cat6A.
Higher-power PoE spreads current across all four conductor pairs, halving heat per pair and enabling higher total.
Marketing names confused everyone. "PoE+" = Type 2. "PoE++" / "4PPoE" = Type 3 or 4. Spec the IEEE name, not the marketing one.
Per IEEE 802.3 standards. Power at PD assumes Cat6A, 100 m run, ambient < 45 °C.
| PoE Type | PSE / PD power | Typical loads |
|---|---|---|
| Type 1 (802.3af) | 15.4 W / 12.95 W | VoIP phone · basic AP · IP camera (no PTZ) |
| Type 2 (802.3at) | 30 W / 25.5 W | Wi-Fi 6 AP · PTZ camera · video phone |
| Type 3 (802.3bt) | 60 W / 51 W | Wi-Fi 7 AP · video bar · thin client · door access |
| Type 4 (802.3bt) | 90 W / 71 W | Video display · PoE LED panel · laptop charger |
| PoE Lighting (premium) | 60 W or 90 W | Cisco DNA, Sinclair Cabling Lighting |
| 4PPoE (4-pair, 60 W early naming) | Synonym for Type 3 | Industry name only |
Five practical gotchas that catch new BAS designers.
A 48-port switch may advertise 30 W per port but only 720 W total budget. Loading every port at Type 2 (30 W × 48 = 1,440 W) exceeds budget, half the ports randomly drop to Type 1. Always check total budget, not just per-port.
100 cables in a tray all delivering Type 3 (60 W) raise bundle interior temperature 10–20 °C. Resistance goes up, voltage at PD drops, and PD reboots. TIA-TSB-184-A recommends de-rating bundles or specifying Cat6A in any bundled PoE design.
On power-up, the PD signals its power class to the PSE via a defined resistor. The PSE allocates that power. A misbehaving PD (or knock-off device) may not negotiate, and pull max regardless. The switch sees high current and protects the port by shutting it down.
If your existing switch is non-PoE, a midspan injector (Phihong, TP-Link, Microsemi) adds PoE on the way to the device. Cleaner than replacing the switch. Saudi retrofit projects use these constantly.
Innovative Lighting (US), MHT Lighting, companies offering full PoE LED systems where the cable is the only power feed. Saves switchgear, allows per-fixture control. Premium offices and new builds (NEOM, Aramco IT campuses) are early adopters. Watch the standards (IEC TR 62862) tighten over 2024–2026.
We supply Cisco, Aruba, and Ruckus PoE switches sized to your full Type-3/Type-4 device load, and certify the cable bundle thermally to TIA-TSB-184-A.
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