Successful PoE Installations

Looking at the challenges of a typical Internet of Things (IoT) rollout, the biggest hurdle usually isn’t how to connect IoT devices to the LAN. Instead getting power cheaply to the device is often a far more difficult problem. Installing AC power outlets next to every IoT device is laborious and cost prohibitive. It’s also overkill considering the relatively low amount of voltage required by most IoT endpoints. Therefore, power over Ethernet (PoE) has become a must-have technology for virtually every enterprise and industrial IoT rollout. That said, PoE installations come with their own set of unique challenges. This means you must possess a certain level of knowledge when it comes to understanding what you need from a power perspective. Let’s go over 3 things you should know to ensure a successful PoE install. 

1. How does PoE Work? 

According to the IEEE, power over Ethernet is comprised of three components: power sourcing equipment (PSE), the powered device (PD) and the cabling used to deliver power to the device. 

Additionally, this cabling is dual purpose in the fact that it not only carries electricity to power the device – but is also used to also used for Ethernet data transport. There are several IEEE PoE standards that exist today. Each one delivers varying power levels from the PSE to the PD. These standards also provide the necessary signaling that both the PSE and PD will understand. The signaling is used to detect whether the PD indeed needs power as well as a negotiation process to determine the amount of power the PD requires for operation. Currently, there are eight different power classes available as defined by the IEEE. The power delivered by the PSE ranges from 4 Watts in a class 1 device to 90 Watts in a class 8 device. To learn more about the most popular IEEE PoE and PoDL standards, check out our detailed blog here. 

It’s also important to know that a PSE can either be a combined Ethernet and PoE switch — or a midspan PoE source that separates the duties of Ethernet switching and PoE delivery. In either case, it’s necessary to know ahead of time which IEEE PoE standards the switch or midspan device can deliver to the PD. Some PD’s such as newer wireless access points or advanced 4K/8K and PTZ surveillance cameras require more power to operate. Thus, it’s essential that you verify the PSE can indeed deliver the appropriate amount of power each PD will need. 

2. Choosing the right cabling 

There are several Ethernet cable standards that PoE can operate across. Some cable types are better than others depending on the wattage your PD’s require. Within common office and manufacturing deployment environments, you’ll likely come across existing four-pair copper cabling using CAT5, CAT5e and CAT6 standards. PD’s requiring lower wattage can utilize this older cabling. However, it’s highly recommended that when powering devices that require 60 W or higher sent over the cabling, newer CAT6A and higher cabling should be run. These types of cables use thicker conductor diameters that helps reduce resistance. This is critical so that power is not lost due to compounding resistance over longer cable runs. CAT6A and higher cabling is also better insulated and can handle the added heat produced by the higher power loads being sent across the wires. This is especially important when running higher-wattage PoE in large cabling bundles. Lastly, thicker cables are far more capable at delivering higher power and faster Ethernet transmission speeds for multi-gigabit connections over twisted pair copper. Thus, running newer cabling future-proofs your IoT investment. 

3. Certify all cabling to ensure it meets stringent standards 

To increase the likelihood that your cabling won’t be an issue when running PoE, it’s necessary to certify cabling to meet the cable manufacturers strict standards. This is true not only in terms of ensuring that the cabling can operate at multi-gigabit speeds – but also to test and ensure proper power load capacity for IEEE 802.3af, 802.3at and 802.3bt standards.