Power over Ethernet (PoE) is technology that passes electric power over twisted-pair Ethernet cable to powered devices (PD), such as wireless access points, IP cameras, and VoIP phones in addition to the data that cable usually carries. It enables one RJ45 cable to provide both data connection and electric power to PDs instead of having a separate cable for each.
PoE technology offers several benefits. First, the delivery of data and power over a standard Ethernet cable eliminates the need for AC/DC power supplies and outlets to give power to PD equipment. That lowers the costs of adding or installing compatible PD equipment since you don’t need an electrician to install power if there isn’t any where you want to place your new PDs. Additionally, regular Ethernet cable is rather inexpensive and is often already installed in the location. Second, with PoE technology in general, there are fewer points of failure. Connect your PoE switch or PoE injector to an uninterruptible power supply (UPS) and your PoE powered devices are guaranteed a constant power delivery, which is important for mission-critical PoE edge devices. Third, PoE installations, which utilize managed PoE switches, offer the ability to remotely restart connected PoE devices. That can be done either manually, automatically or based on a schedule. Modern PoE switches are equipped with watchdog functionality (i.e. Powered Device Manager [PDM]) that cuts power to offline devices and then resupplies it so they reboot. This function helps to greatly reduce the downtime of your connected devices.
Using Power over Ethernet provides a number of advantages during installation:
PoE can reduce the time and expense of having electrical power cabling installed. Network cables do not require a qualified electrician to install. Reduction of power outlets required per installed device saves money. It also reduces energy costs by allowing for centralized control over lighting, window shades, and heating and cooling.
Without being tethered to electrical outlets, devices such as monitors, security cameras, and wireless access points can be positioned in ideal locations and be easily repositioned if moved.
Power delivery using PoE is designed to intelligently protect network equipment from overload, underpowering, and incorrect installation. It also eliminates the danger of working with or around dangerous high-voltage power sources.
PoE power comes from a central and universally compatible source and not from a collection of distributed wall adapters. It can be backed up by an uninterruptible power supply (UPS), allowing for continuous operation even during power failures. PoE also allows for devices to be easily disabled or reset from a centralized controller.
PoE lighting uses Power over Ethernet technology to connect, monitor, and control LED light fixtures used in smart building solutions. Smart PoE lighting reduces installation and operating costs by more than half and helps building owners meet wellness and sustainability goals.
Using PoE to power low-voltage DC-powered LED lighting has many benefits over both traditional lighting options (incandescent, fluorescent and CFL, and halogen) and newer AC-powered LED options.
Using low-voltage LED lighting alone can offer a dramatic reduction in energy required per lumen compared to incandescent and halogen equivalents. But using PoE to power and connect lighting has several significant advantages. It can:
- Reduce up-front construction costs and time to completion when used for cabling, installation, and configuration. There is also a dramatic reduction in carbon footprint, since no conduit or high-voltage copper wiring need to be installed.
- Lower capital expenditures, labor, and materials costs related to construction and maintenance.
- Allow for greater flexibility in design and placement.
- Enable the optimization and quantification of energy consumption by using the building’s network as a sensor and interconnecting shades. This saves money and reduces carbon footprint.
- Require less energy, run cooler, and be a smaller form factor since no AC/DC transforming or transformer is required.
- Power, monitor, and control LED lighting, IoT devices, and centralized and automated environmental controls.
- Improve lighting through automation. Personalized environments can attract tenants and increase revenue per square foot.
There are several key differences between DC-based PoE lighting and AC-powered LED lighting.
LED lights need DC power to operate, so AC-powered LED fixtures need a transformer to convert their power source to DC. This can result in a 20 percent loss in power. In addition, the transformer itself can be bulky, and it emits heat because of the conversion.
AC power also requires heavier gauge wire, a conduit, and an electrician to install. With PoE, common Ethernet cabling is used. And because of the low power, it can be safely installed without an electrician. This reduces installation costs, speeds time to completion, and allows for more flexible fixture placement.
PoE lighting can be readily paired with sensors, shades, and HVAC controllers without requiring a separate data cable.
A smart building (often referred to as property technology or PropTech) converges buildingwide systems—such as HVAC, lighting, alarms, and security—into a single, IT-managed network infrastructure. It often uses foundational technology such as Power over Ethernet to accomplish this convergence.
PoE has evolved from providing 15W of power across Ethernet cabling to providing 90W. With that evolution, the number and types of devices that can be powered and connected by PoE have grown dramatically. Using PoE to power and interconnect devices has several advantages:
- Greater flexibility for hybrid workplace
- Lower cost to deploy than using AC power
- Lower cost to operate than using AC power
- Greater insight, control, interconnectivity, and automation
In a smart building, PoE can power devices such as lighting, sensors, HVAC systems, shades, and alarms, as well as USB-C laptops, TV and computer monitors, refrigerators, and room air conditioners.
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