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Tips on Using PoE Extenders in Long Range Applications

PoE extender is a cost-effective solution to overcome the geographic challenge of Ethernet (only supports a maximum distance of 100 meters/328ft) by repeating the PoE signals over the long cable runs to establish a long-range network connection between two geographically separated network devices. It is often utilized in long-distance applications, for example, to connect different workstations within the same building. In today’s post, we will introduce some useful tips on PoE extenders in long-range setups.

What is a PoE Extender?

The PoE extender is the updated version of the traditional Ethernet extender, a mutual-benefit networking device that extends both power and data connection to the remote edge device on a twisted-pair cabling system, while the fiber media converter and the Ethernet extender only support data connectivity (additional power cabling might be required if there is no available electrical infrastructure). It uses the existing twisted-pair cabling to deliver electrical power over the same Ethernet data stream to the next connected device (i.e. another PoE extender or a powered device). Like other PoE solutions, the PoE extender is hot-swappable and comes with a plug-and-play design, which greatly simplifies the network installation in the field.

Troubleshooting: Problems of Using PoE Extenders & Solutions

The PoE extender can allow for a number of advantages including flexibility, cost savings, simplicity, and reliability. But these benefits cannot be always guaranteed. Instead, they can easily be turned into disadvantages when misapplied. Consequently, there are a number of factors users should be aware of when using PoE extenders for long-range setups.

Problem 1: The Risk of Water Ingress in Outdoor/Humid Environments

When deploying PoE extenders in wash-down areas or high-humidity places, one of the common reasons for network failure is water getting into the connection between the PoE extender and the Ethernet cable. If water infiltrates, irreversible consequences may occur. It will cause some problems like disconnection, short-circuit, etc. Water ingress can also cause corrosion on the metal pins inside the connection which will interfere with power and data delivery. And in severe cases, it’ll also give rise to some safety hazards like electrical shocks.

Solution: When deploying PoE extenders outdoors, it’s also recommended to choose one that can withstand the physical ingress hazards. Most outdoor PoE extenders are built with an IP or NEMA-rated enclosure to protect the devices against water penetration, dust ingress, penetrative articulates, vibration and shocks, or chemical exposure. But even the direct burial-rated PoE extender, for example, rated IP67 waterproof, can only provide a certain degree of protection, so it’s possible that moisture would make its way into the connection part. So when using Fastcabling’s PoE extender, you must use a 27mm wrench to fasten the glands on both ends. If the gland is not fastened tightly enough, water may ingress into the PoE extender and damage the PCB board.

Problem 2: Power Surges Occur During Lightning Strikes

If you’re using network devices or Ethernet cables outdoors, you may want to give them extra protection to limit the damages caused by lightning strikes while installing long-run network applications in severe weather conditions. In mild conditions, a lighting storm will cause the PoE extender to reboot. But in some cases when the copper cable (Cat5/6 cable) gets hit by lightning, the copper cable will absorb the surges and transmit them to both ends so as to pass them to the ground, which will eventually damage the connected device.

Solution: you should always take some precautions to protect your devices and appliances from power surges, especially in long-range applications. If large enough, a power surge can cause permanent damage to the PDs. So to prolong the service life of your network devices and prevent the need for costly repairs, you’ll need to install the surge protectors at both ends to regulate the flow of electricity. The surge protector makes sure your events function more reliably and protects the connected devices from damages during sudden power surges. Waterproof Ethernet cables are more likely to withstand lightning strike damages, but if possible, choose an Ethernet cable that can withstand power surges of 6kV during stormy weather.

Hint: When choosing an appropriate network cable for your outdoor project, you need to remember that it has to withstand the adverse conditions of the outdoor environment. For safe operation, you should choose one that is waterproof, shielded with a UV-resistant jacket designed to withstand UV exposure, snow and ice. And it’s highly recommended to use direct burial cables that can be buried under the ground with conduits. For outdoor applications, you should always go for the CMX cables that have a great tolerance for extreme temperatures, water ingress, etc., and they also block the UV light to prevent degradation in long-term use.

Problem 3: Limited Power Capacity over Long Cable Runs

There is always power loss during the transmission, especially in long-distance deployments. Theoretically, the longer the distance, the more power loss will be. The power will be dissipated as heat and vanish in the air, and eventually, you experience severe voltage drops over the long cable runs. And high heat dissipation and power loss are two big concerns deploying PoE outdoors.

Solution: When you want to use PoE over long distances, you can use pure copper cables at best. The pure copper cable is made of 100% copper and it has great conductivity, suitable for a length up to 100 meters. But if you’re using a CCA (Copper Clad Aluminum) cable, its performance will start to deteriorate when it hits 10 meters. Normally, the CCA cables only serve as a temporary solution and are only suitable for applications under 50 meters. Because the conductivity of the aluminum is worse than that of the pure copper cable, it’ll experience greater DC resistance and therefore generate larger power loss.

Problem 4: Compliance Issues When Connected to Non-PoE Devices

Users can run into lots of issues when connecting the PoE extender to a non-compatible/non-PoE device. Since most legacy devices don’t come with an RJ45 interface, to connect a PoE-enabled PSE with a not PoE-compatible PD. So if you want to deliver power in parallel

Solution: The PoE splitter is a useful network device that you can use to mix the PoE and non-PoE devices. It powers a non-PoE device by splitting PoE from a unified network cable and delivering power and data through separate outputs. It often works with a PoE switch or a PoE injector to power non-PoE devices in hard-to-reach areas which is hard to find a power outlet, eliminating the need for additional AC wiring. The PoE splitter can also be used to bring a 48V DC current down to a low voltage electrical current (regulated 5, 12 or 24V), enabling the safe connection to devices with a low input voltage range.

Problem 5: Problems Arise When Connected to Passive PoE Devices

The PoE extension solution never works with DC24V passive PoE. When the power is lower than 36.5V, the PoE extender will enter the protection mode and shut down the transmission. Moreover, the 24V is too voltage to adapt to the power loss during the long-range application. It’s important that you know the voltage of the connected device, or it will be burnt down.

Solution: To ensure the safe operation of the PoE extenders, you must use standard PoE only. The PoE extenders that are compliant with the IEEE802.3 standards are inherently safer. Before the PSE sends any power to a connected PD, it will initiate a negotiation procedure called ‘power handshake’ to verify if the PD is PoE-compatible and it’ll then decide how much power the connected device requires. But the power handshake is only available in active/standard PoE devices. On the contrary, in passive/non-standard PoE, no negotiation process will take place since such devices could only operate at a pre-defined voltage. So always choose one PoE extender that supports standard PoE.

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