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Table of Contents
Surge Protection
A receiver mounted outdoors (balcony, railing, mast) is usually powered via PoE, which means an Ethernet cable runs from outside straight to a switch or router indoors. Thunderstorms in the area can induce voltage spikes on such outdoor cable runs, damaging the connected network equipment. An Ethernet surge protector (surge arrester / voltage limiter) diverts these spikes to earth before they reach the devices inside.
In short: one surge protector per outdoor cable run, installed inline into the LAN cable before the switch, and it must be grounded – without grounding the device does nothing.
When do you need it?
- Receiver outdoors, switch/router indoors → plan for a surge protector.
- Fully indoor installation (e.g. receiver on the windowsill behind glass): not needed.
- A surge protector guards against induced surges (nearby lightning, static build-up). It does not protect against a direct strike – that would require a proper lightning protection concept from a professional.
What is at risk?
A surge induced on the outdoor cable travels down the line and can destroy whatever is connected to it. There is no guarantee the receiver itself survives – but at ~€20 it is cheap to replace, and the same goes for a PoE injector (~€20). The main financial risk sits at the indoor end of the cable: a PoE switch (€100 and up) feeding an unprotected outdoor run can get fried, and in the worst case the damage does not stop there – other devices on the network can be hit as well.
Device
A proven option is the Ubiquiti ETH-SP-G2 (Ethernet Surge Protector, approx. €13):
| Property | ETH-SP-G2 |
|---|---|
| Connection | 2× RJ45, installed inline into the LAN cable |
| PoE | passed through – 802.3af power for the receiver keeps working |
| Data rate | Gigabit-capable (the receiver only uses 100 Mbit anyway) |
| Mounting | weatherproof, suitable for outdoor installation |
| Grounding | screw terminal – grounding wire is not included |
Installation
- Position: inline in the outdoor run, before the switch – i.e. at the indoor end of the cable, as close as possible to where it enters the building. With several outdoor runs, each run gets its own surge protector.
- Grounding (mandatory): connect the grounding terminal with ≥ 4 mm² copper wire (green/yellow) to protective earth / equipotential bonding (PE). Without grounding the surge protector is useless, because the diverted surge has nowhere to go. The wire has to be bought separately.
- Outdoor connectors: keep them protected (outdoor box / covered), cable entries facing down, add drip loops – then connectors outside are uncritical.
See also
- faq – PoE vs. USB power, jumper settings
- hardware_setups (German) – PoE variants (802.3af / passive)
- externe_antenne (German) – outdoor mounting with an external antenna