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 LED lighting can be readily paired with sensors, shades, and HVAC controllers without requiring a separate data cable.

Low voltage power is transmitted over existing Ethernet cables to operate the luminaires, while high volumes of data are sent and collected. Integrating a LEDCET connected lighting system using Power over Ethernet (PoE) technology into the IoT is an ideal way to meet sustainability goals and realize financing savings from space optimization and employee productivity.

What is a smart building?

A smart building converges building-wide systems (often referred to as building management systems - BMS, or building automation systems - BAS) including HVAC, PoE lighting, shades, alarms, and security—into a single, IT-managed network infrastructure. It often uses foundational technology such as Power over Ethernet to accomplish this convergence.

What is the role of PoE in a smart building?

PoE has evolved from providing 15W(IEEE802.3af) of power across Ethernet cabling to providing 90W(IEEE802.3bt). 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.

What are the IEEE 802.3af, IEEE 802.3at, and IEEE 802.3bt standards?

The IEEE 802.3 standards from the Institute of Electrical and Electronics Engineers (IEEE) define Ethernet. The 802.3af, 802.3at, and 802.3bt standards define common techniques used to transmit power over copper Ethernet cables (PoE).

IEEE PoE standards have significantly evolved since the initial IEEE 802.3af standard, which defined up to 15.4W of DC power. The IEEE 802.3at standard increased power up to 25.5W.

The latest standard, IEEE 802.3bt, was published in 2019 and allows for significantly more power—up to 100W. This ability to deliver high-speed connectivity over LAN connections helps enable many new applications.