The use of power-over-Ethernet devices has grown dramatically in recent years, especially with ratification of the IEEE 802.3bt standard in 2018. Endspans and midspans designed under this new standard can deliver up to 100 watts of power to devices, using all four wire pairs of a Cat6 Ethernet cable. Benefits of this improvement include:
- The use of security cameras with more advanced features, such as 1080p HD quality, night vision and motion detection.
- Improved wireless access points to accommodate the ever-growing needs of mobile data services.
- More flexibility in the placement of point of sale (POS) terminals, which with PoE no longer require AC outlets.
- More flexibility and efficiency for telecom providers who opt to use small cell networks in place of large cell towers.
Of course, all PoE devices require protection from power transient and surge events such as lightning strikes. Well-designed surge protectors will divert the energy to ground and then reset, ready to protect again. Under extreme events the SPDs will self-sacrifice, protecting the PoE equipment. They can then be easily replaced with a minimum impact on the system’s operational status.
L-com has provided connectivity products since 1982, well before PoE emerged, so we have gained a lot of wisdom about how to protect PoE/Ethernet lines. Below are the six most essential things we have learned.
- PoE Devices Need External Surge Protection
Though some PoE devices – such as radios, power injectors and midspans − have integrated surge protection, it is far safer to deploy external SPDs instead. If the surge protector in an integrated device is damaged over time by low-level surges or disabled by one high-level event, either way the entire device will have to be replaced immediately. This will require you to shut down your system. With external SPDs, however, your PoE devices remain protected and the worst-case scenario is that the SPD must be replaced. Also, high-quality external SPDs perform a single function and do it better than integrated protectors. They reduce or eliminate the need for site visits, maintenance and downtime.
- PoE Devices Need Hybrid Surge Protection
To protect your most crucial data signals in a PoE-fed device such as a camera, we recommend using a hybrid surge protection design with both silicon avalanche diodes (SADs) and gas discharge tubes (GDTs). This two-stage SAD/GDT guard acts fast, has a high surge capacity, does not degrade and can maintain system voltage while deflecting surge. L-com’s TSJ line of data surge protectors is an example of our products with SAD/GDT technology. There are four models: 5 GbE, 5 GbE PoE, 10 GbE and 10 GbE PoE.
- Protect Both Ends of an Ethernet Line
Your Ethernet cables and PoE devices can receive surge energy from different sources at numerous points. Direct or indirect lightning strikes can be the culprit, or nearby surge events that energize the earth around critical loads. Best practice is to install SPDs at both ends of the Ethernet line, providing protection in either direction of the cable to shunt the surge energy away from the critical loads (PoE camera and PoE switch).
- Future-Proof Your System
When purchasing SPDs, it is smart to keep your future needs in mind. Using gigabit Ethernet/PoE++ SPDs allows the protection infrastructure to remain in place if the PoE-fed equipment must be replaced or upgraded. The PoE++ designation means they can support devices that need higher wattage, such as videoconferencing components and building management devices.For examples of such devices, check out L-com’s TSJ-5G-BEPOE-LC and TSJ-10G-BEPOE-LC.
- Use Shielded Transmission Lines
A best practice is to use shielded cables, shielded receptacles and dedicated shield-to-ground protection in the SPD to harden the signal line. Ethernet cables without proper shielding can allow a surge event to be transmitted along or in the cable. L-com’s wide variety of shielded products include this 10 GbE PoE data surge protector, which has shielded RJ-45 connectivity.
- Use NEMA Enclosures Outdoors
For outdoor applications where hardware may be exposed to harsh environments, it is critical that the equipment is installed inside NEMA-rated enclosures. L-com has a vast selection of weatherproof NEMA enclosures in different sizes, materials and protection ratings including our popular fiberglass enclosure lineup.
L-com offers hundreds of surge protection and PoE products. In addition, we offer DC surge protectors for those who need this kind of lightning protection. And, we carry a wide range of AvaLAN products. We also pioneered same-day shipping. In fact, even in this time of supply chain challenges, our facilities are fully stocked and ready to support your business. Questions? Call us toll-free at 1-800-341-5266, chat with us live, or email us at sales@l-com.com.
