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An Introduction to Power Over Ethernet (PoE)

Smart city

The building revolution is upon us, and today’s cabling technologies lead the way, connecting current speed requirements to tomorrow’s technologies. Nowadays, we can open our garage doors via Wi-Fi, identify people with a fever from a distance, conduct meetings a thousand miles away, and detect vaping in office buildings without ever leaving our cubical.

Poe single cableAs impressive as the technologies are, they did not mature overnight. From copper to fiber optics, wired technologies to wireless, each has matured as industry standards are introduced and innovation takes hold. It is commonly believed the exponential growth of all technology relates to Moore’s Law*, sometimes called the law of exponential growth. Just as semiconductors have become smaller and more powerful using less power, cabling has seen similar technological advancement in support of end devices that have been traditionally powered by high-voltage AC.

Power over Ethernet (PoE) is one such technology. PoE is a continually maturing technology that allows network communications and electrical power delivery through a single cable. For example, a digital security camera that generally would require two connections to be made when installed (one to carry the video signal and another delivering electrical power) can now be made with a single cable.

Why use POE in lighting?

Lighting costsLighting alone can account for about 20% of a company’s utility costs.

High-efficiency light fixtures have driven down utility and maintenance costs, but this is one of only a few reasons why lighting is going through a significant transformation. The way lighting is controlled makes it possible to bring illumination and IT together.

Applying PoE to control lighting is at the core of a digital building revolution. PoE lighting merges technological advances in low voltage (DC) LED lighting with innovations in PoE IP networking. Integrating these advances creates an exciting Internet of Things (IoT) component that could provide significant cost savings and unforeseen benefits to how we work and live.

The integration allows for data collection, such as analytics software to help facilities managers determine when an area is occupied and when lighting and the HVAC system can be turned off, maximizing energy savings. Additionally, analytics can provide valuable information on space utilization and occupancy levels.

PoE also lets equipment be installed remotely or outside of the building without requiring an AC connection. This allows power delivery to more locations without requiring additional electrical infrastructure or power outlets at every endpoint. Comparatively, utilizing low-voltage Category cabling as the medium is less costly than traditional AC power, which requires conduit and high-voltage wiring.

What are the advantages of PoE?

Installing Power over Ethernet brings several advantages in an installation:

  1. Poe cabling infrastructureTime and cost savings – Licensed electricians can get expensive. With PoE, low-voltage Category network cables are the primary medium, and labor costs are typically lower with low-voltage contractors. Not to mention, because PoE can be located anywhere, there is no need to drop or install AC power at the end device.
  2. Scalability – Power available anywhere means your network can grow with you. You can use your existing cables to upgrade your PoE switch or injector if you need more power, or you can just expand your existing cabling infrastructure with additional Category cables.
  3. Safety – PoE Type 3 and 4 voltages are typically less than 90 volts. This is considered a low-voltage circuit, with 120 volts of DC power considered the “safe limit” for direct contact. Conduit and metal cladding are also not required. The fewer steps and hazards and the simplicity of Cat5e or Cat6 cabling remove the need to have a licensed electrician.
  4. Flexible placement – Electrical outlets can limit where you place cameras, access points, and other devices. With the need for an outlet, you are not tethered to a specific location. Move them wherever they are needed most and repositioned them as required.
  5. Scalable Power – Need a device that only requires 4 watts? It will only use 4 watts. PoE allows devices to draw as much energy as needed. In cases like PoE Lighting, the lighting fixtures can be cascaded together rather than having independent Category cabling for each fixture.

Power over Ethernet Applications

Poe environmental sensorsInitial PoE developments covered Voice over IP (VoIP) phones and wireless access points but have steadily increased to include several diverse applications. Within smart buildings, PoE is ideal as an aggregation point for numerous wireless devices. More than just room lighting management, occupancy detection, and heating, ventilation, and air conditioning control (HVAC), external environmental sensors can optimize building management platforms, syncing with big data to support energy savings and improve occupancy comfort and safety. Key applications include:

  • VoIP phones – Using PoE enables phones to have a single connection to a wall socket and be powered down remotely, similar to older analog systems.
  • IP cameras – Networked surveillance cameras enable rapid deployment and easy repositioning.
  • Wireless technologies – Wi-Fi and Bluetooth APs and RFID readers are commonly PoE-compatible to allow remote location away from AC outlets and relocation following site surveys.
·       Ethernet Extenders

·       PoS Kiosks

·       LED Lighting Systems

·       Network Switches

·       Routers

·       Wireless Access Points

·       IP/Pan-Tilt-Zoom Cameras

·       VoIP Phones

·       Security Access Controls

·       Industrial Controls

·       Digital Signage

·       Smart Clocks

Are you feeling a bit more enlightened? Let PoE Lighting and NCS show you the benefits.

Poe building managementMerging the traditional power sources into ethernet cabling provides smart buildings an effective approach to extending the reach of cameras, sensors, and other platforms. It is part of a complete energy management system that makes intelligent buildings even smarter.

For more information about the technologies and applications discussed in this article, contact your NCS representative or visit our website at

*Moore’s law states, “The number of transistors in an integrated circuit (IC) doubles approximately every two years.”


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