# Power-over-Ethernet for Outdoor Node Deployments

Power over Ethernet (PoE) is an excellent choice for outdoor nodes at sites with structured cabling infrastructure. It combines power delivery and network connectivity in a single cable, simplifying installation and enabling remote management.

## PoE Standards

<table id="bkmrk-standardmax-powertyp"><thead><tr><th>Standard</th><th>Max Power (at PSE)</th><th>Typical Use</th><th>Common in</th></tr></thead><tbody><tr><td>IEEE 802.3af (PoE)</td><td>15.4W</td><td>IP cameras, VoIP phones</td><td>Most infrastructure</td></tr><tr><td>IEEE 802.3at (PoE+)</td><td>30W</td><td>PTZ cameras, APs</td><td>Modern switches</td></tr><tr><td>IEEE 802.3bt (PoE++)</td><td>Type 3 = 60W; Type 4 = 90W (≈71W delivered at the powered device)</td><td>Laptops, high-power APs</td><td>Newer switches</td></tr><tr><td>Passive PoE (non-standard)</td><td>Varies</td><td>Low-cost IP cameras, some APs</td><td>Ubiquiti older hardware</td></tr></tbody></table>

The 802.3bt maximum is 90 W at the power-sourcing equipment (Type 4), not 100 W — "100 W PoE" is a marketing rounding, not the IEEE spec figure.

For mesh nodes, IEEE 802.3af is more than sufficient. Most nodes consume 1-5W.

**Active vs. passive PoE — not interchangeable.** Standard (802.3af/at/bt) PoE negotiates voltage between the switch and the device (roughly 44 - 57 V) and is safe for compliant gear. Passive PoE simply puts a fixed voltage (often 24 V or 48 V) on the cable with no negotiation, and can damage equipment if mismatched. Match injector, splitter, and node carefully — a passive 24 V injector paired with a splitter that expects active 48 V may deliver no power or fry the node.

## Maximum Cable Run Distance

PoE follows the Ethernet 100m (328 ft) cable run limit. Choose by distance:

- **Single run ≤100m:** a standard PoE run works directly.
- **~100 - 200m:** use a PoE extender (repeater) at the 100m mark to extend another ~100m.
- **Beyond ~200m:** use a fiber optic run with a media converter.
- Use cellular or WiFi for power-independent remote nodes.

Note: independent of distance, a fiber optic break between the building and the node is also the strongest *lightning* isolation option (see below) because fiber is dielectric — consider it on any outdoor run in a high-lightning area, not only for long runs.

## Lightning Protection for PoE Runs

An Ethernet cable run to an outdoor node creates a lightning risk - the cable can couple surge energy into your equipment:

- **Ethernet surge protector:** Install a PoE-compatible Ethernet surge protector (e.g. Ubiquiti ETH-SP-G2, ~$15 as of 2026-06-08 — confirm current price on the [Ubiquiti store](https://store.ui.com/)) at both the building entry and the outdoor node enclosure. This is essential for any outdoor Ethernet run.
- **Fiber optic break:** Insert a fiber optic run between the building and the outdoor node. Fiber is dielectric - it cannot carry surge current. Best protection option.
- **Grounding:** Properly ground your outdoor enclosure and the surge protectors. The surge protector's ground and the enclosure ground must be bonded to the **same grounding electrode system as the building's AC ground** (per NEC 250.94) — bonding to a separate, isolated ground rod creates dangerous ground-potential differences during a strike. Tie all ground connections into that single building grounding electrode system.