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
| Standard | Max Power | Typical Use | Common in |
|---|---|---|---|
| IEEE 802.3af (PoE) | 15.4W | IP cameras, VoIP phones | Most infrastructure |
| IEEE 802.3at (PoE+) | 30W | PTZ cameras, APs | Modern switches |
| IEEE 802.3bt (PoE++) | 60-100W | Laptops, high-power APs | Newer switches |
| Passive PoE (non-standard) | Varies | Low-cost IP cameras, some APs | Ubiquiti older hardware |
For mesh nodes, IEEE 802.3af is more than sufficient. Most nodes consume 1-5W.
Maximum Cable Run Distance
PoE follows the Ethernet 100m (328 ft) cable run limit. For outdoor nodes at distances greater than 100m from the PoE switch:
- Use a PoE extender (repeater) at the 100m mark to extend another 100m
- Use fiber optic run (with media converter) for runs over 200m - eliminates lightning coupling between building and node
- Use cellular or WiFi for power-independent remote nodes
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 (Ubiquiti ETH-SP-G2, $15) 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. Bond all ground connections to a single earth ground point.