PoE (Power over Ethernet)

Powering devices in buildings – A Revolution is taking place.

Networks in buildings continue to expand, growing more versatile and complex. Wireless access points (WAPs), security cameras, building automation and control systems, voice-over-IP (VoIP) phones etc —are now important network assets. As more devices are added, the cabling infrastructure needs to support them and the option to power them over structured cabling becomes more attractive, providing both power and data to many network devices via Power over Ethernet (PoE) over one UTP cable. Since 2002, PoE has gradually gained momentum in the market. Today, PoE is the new power grid in buildings.

The original PoE standard—IEEE 802.3af, adopted by the IEEE PoE Task Force in 2003, limited the technology to devices requiring less than 12.95 watts of power. Less than three years after the first standard was published, growing demand for PoE applications beyond 12.95 watts led to efforts to update it. The revised PoE standard, IEEE 802.3at—also known as PoE Plus or PoE+—was adopted in 2009 and raised the PoE power supply to 25.5 watts. Since then, the industry’s interest in, and demand for, higher power PoE solutions has continued to snowball. IEEE 802.3bt is the latest PoE standard and allows for a twisted pair cable to carry data and 90W of electricity to devices like wireless access points, the most robust security cameras, and digital signs. PoE now delivers 99Watts


New PoE standard 2X increase in pairs, 50% increase in current, 3X increase in power.

PoE describes a system to safely transmit electrical power—along with data—to remote devices over standard structured cabling. PoE is designed so Ethernet data and power signals do not interfere with each other, thereby enabling simultaneous transmission without signal disruption.

PoE works by converting the mains power supply into a low-voltage supply, then transmitting the power over structured cabling to PoE-enabled devices.

The PoE system consists of the power sourcing equipment (PSE), which supplies the power, and the powered device (PD), which receives the power. PSEs are typically designed as end-span or mid-span power supplies. The end-span PSE is typically built into an Ethernet switch port, with an estimated 100 million PoE-enabled ports shipping annually. As the name suggests, the end-span PSE resides at the LAN endpoint opposite the PD.


So, why should you use PoE to power devices in your building?

Why? Because it’s simple:

  • Easier installation
  • Cost effective installation
  • Easier network management
  • Uses smart power technologies
  • Uses DC power
  • Ability to perform power/energy management

PoE runs over the same copper cabling that is supplying bandwidth to your WAP, security camera, or lights. The one cabling contractor installs and commissions the cabling that now delivers data and power. Plug-and-play features further simplify the installation. Install the device and cabling, connect to the PoE switch, and you are up and running. Add in Cyber security and that’s it.


Need to add or move devices, change density, or adjust the locations?

PoE provides flexibility to do just that, with no electrical outlets to install or move. LED lighting powered by PoE is one of the most meaningful developments. Our need to add or move WAPs to address density, or adjust the location of a camera is also great. Easy with PoE. Benefits include increased energy savings and lower deployment costs, along with simplified installation, flexibility, and improved reliability for powered devices.

It is important to understand that the cables and connectors, by themselves, can handle the current and power levels associated with delivering PoE. The concerns with running PoE in cables is to do with heat and temperature rise that occurs when the cables are bundled, and the concern with connectors is the arcing that can occurs when a plug is removed from a connector with live PoE. Concerns include:

  • Some temperature rise will increase cable insertion loss and may create bit errors for your application.
  • Extreme temperature increase past the recommended cable operating range can create long term damage to cable
  • Arcing can damage plug and jack contacts and make transmission difficult

In summary, it has never been more important to specify a cable manufacturer that takes testing seriously and an authorised Installer that knows what they are doing!


Some recommendation to allow margin and flexibility for 4-pair PoE:

Category 6A cabling – To improve thermal performance and energy efficiency while minimising the cost of moves, adds, changes, the recommendation is to use Category 6A cabling to each powered device, preferably using a zone cabling architecture. The TIA TSB-184-A and ISO/IEC TS 29125 recommend the use of Category 6A cabling for 4PPoE.

Reliability testing – If connectors are unplugged under load, an inductive current is created within the connector that may spark at one or more contact surfaces, causing the surfaces to corrode. It is recommended that connecting hardware be qualified to support PoE and 4-pair PoE applications by using the test schedules in IEC 60512-99-001.

Bundle size – for heating and mechanical reasons, bundle size should be limited to 24 cables.



As IoT devices are set to reach 50 billion, PoE has become the defect standard for power and data delivery. High performance cable infrastructure is the base layer for these smart technologies. Cyber Security is a must-have skill set, so your selection of a competent contractor has just become even more challenging. Kedington have all these skill sets in-house. We are the contractor that can prevent your clients’ networks from being hacked. We can design, supply and install a secure PoE Building Services Network, offering a robust platform for all these different devices that need to run over a single network. With lower installation costs, fewer hazards, more flexibility, PoE is a proven, viable, cost-effective solution.

Please ask Kedington to help.