February 22, 2019
ESD (Electrostatic Discharge)
This is a build up of electrically charged particles that can wreak havoc with your devices if not adequately protected. Lightning storms are a prime example of ESD build up. Turbulence in storm clouds causes a build-up of electrical charges that ultimately result in a lightning strike. Even when there is no visible lightning, friction caused by small particles colliding with the device creates a static build up which eventually discharges onto the electronics. If powerful enough, this discharge can travel through the PCB of the device, out the Ethernet port and down the Ethernet cable to the devices below.Surge Damage
On the reverse side of things, Surge Damage attacks your network from the opposite end (ground upwards) and is typically defined as a rush of power which exceeds the device's tolerance level. For those of us experiencing power failures/outages, these surges are common as once power is reinstated, there is a rush or surge of current flowing back to devices which often causes damage if the proper precautions have not been taken.
While your PoE injector may offer some form of surge protection, if the surge is powerful enough, as in the event of a lightning strike, it may very well damage the PoE injector's surge protection and keep travelling up the Ethernet cable to your active equipment, causing a surge on your PCB. Without any surge protection installed you will most likely be in the market for a few replacements.
Device manufactures vary and some active devices are supplied with built-in surge protection, however, for external devices an added layer of protection is always recommended.
Grounded Ethernet Surge Protector
UB-ETHSP
Earth Grounding and Surge Protection
UPOE-24G24W
How it works:
How the damage is caused and how to prevent it!
When a surge hits your power source, a rush of electricity is sent catapulting towards your devices. The guidelines below highlight some countermeasures available to prevent permanent damage.
- Install battery back up. This allows your device to remain powered at the time of the power outage, either giving you enough time to properly power down the device or to continue operating the device for the duration of the power outage. It aids in preventing surges as the inverter automatically controls the output voltage.
- Always use shielded cable along with shielded RJ45 connectors. This shielded cable and connector is conductive and allows the surge to leave your device on the shielded cabling via the shielded RJ45 connector and be defused by a grounded surge protection unit. If no surge protection is installed the surge travels along the shielded cable to the next device until the surge has diffused.
- Surge protection units. Even if your device or PoE injector comes with built-in surge protection, add an extra layer of protection by installing a grounded Ethernet Surge Protector both at the top of your tower and at the bottom close to your router. (UB-ETHSP)
In a typical installation as shown below, both the surge protectors (UB-ETHSP) are installed and grounded. When a surge strikes, the voltage will travel through the router/switch and before reaching the CPE, will be defused by the grounded surge protector. Should the surge originate at the CPE, the voltage will travel through the CPE and be allowed to exit the CPE on the shielded RJ45 connector, travel down the shielded cabling, into the surge protection unit which is grounded to the pole, the surge then travels down the pole and is defused into the ground.
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| Shielded Outdoor Cat5e Cable | Shielded Outdoor Cat5e Cable | |
| TC-305 | TC-100C |
Distributors generally extend the manufactures warranty onto their clients and with most manufactures refusing to warranty any device that shows signs of surge damage, the cost of taking the necessary precautions its definitely well worth it.
References:
https://en.wikipedia.org/wiki/Electrostatic_discharge
https://en.wikipedia.org/wiki/Static_electricity
https://www.school-for-champions.com/science/static_lightning.htm
https://www.keyence.com/ss/products/static/resource/feature/index.jsp
https://www.esdtile.com/content/does-airflow-create-static-electricity
