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What is Power over Ethernet?

Through the use of Power over Ethernet (PoE) technology, an Ethernet cable with twisted-pair construction can also deliver power to electrical equipment. The wiring of any such arrangement is substantially simplified by the use of only one wire, which is most frequently encountered in Internet of Things (IoT) devices like IP security cameras. It is more convenient and also more affordable when such devices may be installed in difficult-to-reach areas where running any wiring is difficult.

What is Power over Ethernet?

The general technique that makes it possible to transmit data and supply power over an Ethernet network connection is known as “power over Ethernet.” In practice, PoE consists of a PoE-capable device, a regular Ethernet connection, and a PoE-capable network switch. It is also feasible to utilize a non-PoE switch and a PoE injector to supply power to a PoE device on the network, but this injector will need its own main power connection.

To power and connect Voice over Internet Protocol (VoIP) phones to a network using just one cable and to make it simple to remotely turn off such devices when not in use, PoE was originally designed for use with VoIP phones. Since then, it has been expanded to make IP cameras, outdoor radios, IP TVs, network routers, access control points like intercoms and entry card scanners, remote point-of-sale kiosks, industrial control systems, to mention a few, easier to wire. But Wi-Fi access points are where most people use it in their homes. This is especially prevalent in mesh networks, which call for a number of routers and nodes.

How does Power over Ethernet work?

Copper wires are twisted into pairs to create all types of Ethernet connections. The same pairs that transfer data also make it possible for power to be transmitted down the cable. A portion of that power is accepted by the power source device, such as a PoE switch or an injector, and the remainder is sent through the Ethernet cable to any attached PoE devices.

Power over Ethernet can be delivered using one of three established methods. Alternative A (or Mode A), Alternative B (or Mode B), and 4PPoE are their names. For Alternative A PoE installations (for 10Mbps and 100Mbps speeds), the power and data are transmitted on the same cables, whereas Alternative B transmits the power on separate lines from the data. The 4PPoE standard transmits power and data using all four pairs of twisted-pair cable. This enables faster network speeds and improved power delivery.

Which Ethernet cables support PoE?

PoE does not require any special cabling, but you must select an Ethernet cable of a high enough caliber to ensure that power and data can be transmitted without interruption. The most recent types of cables have a minimum quality level that guarantees you’ll obtain a dependable PoE connection, even though the performance and quality of Ethernet cables might vary significantly depending on the Ethernet cable you choose. In light of this, Category 5 (Cat 5) Ethernet cables should be regarded as the bare minimum category of cables utilized for Power over Ethernet, with more recent cable generations being used for Gigabit Ethernet with PoE or connections with higher bandwidth.

The only restriction with this advice is that the cable must be constructed entirely of copper wiring. CCA, or Copper-Clad Aluminum, refers to some less expensive Ethernet connections that essentially wrap an aluminum wire in a thin layer of copper. It is not advised to use CCA Ethernet cables for PoE networking, regardless of the desired bandwidth, as aluminum is not a very good electrical conductor.

How much power can PoE provide?

PoE may deliver quite a lot of power if necessary, enabling some more demanding PoE devices, even though it normally supplies very low-level power for modest connected devices. Up to 15.4 watts of DC power can be delivered on each port under the basic Power over Ethernet specification, although this often drops to 12.95 watts at the device due to power loss along the cable’s length, which is more noticeable with longer lines.

More modern specs can offer 25.5W, 51W, or even 71W per port, with each requiring more from the power source, whether it is a switch with PoE capabilities or a PoE injection device.