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Industry Insights

CTD: The Convergence of Power, Light and Data

Wednesday, October 19, 2016 | by Rudy Montgelas

The Convergence of Power, Light and Data

Data: Enabling An IoT Infrastructure With Ethernet

With devices and applications leveraging the IP for communication and the Ethernet providing a standard method for delivery, we are seeing the convergence of connected devices over Ethernet. This allows for IoT networks to be designed and managed alongside existing and evolving industry standards, including the TIA and IEEE, to ensure safe and consistent operation of devices on a common infrastructure.
 



PoE: Ethernet Cabling Systems Are A Viable Path For Power
 

Applications converging over IP allow communications to occur over Ethernet, a common standard which has evolved to support both data and low voltage power over industry standard category cabling. Many of the applications mentioned previously are also leveraging devices, or “Things”, that have become more power efficient. With these devices having lower power requirements, they are now able to be powered using low-voltage direct current (DC) over a single twisted pair cable. The IEEE sets the standard for Power over Ethernet (PoE) which allows for the simultaneous transmission of data and low-voltage power over twisted pair cabling. There are also other solutions in the market that support transmission of power and data, including Cisco’s UPOE solution and the A/V industry’s Power over HDBaseT (PoH).

Current IEEE PoE standards allow for devices under 30 watts to be powered and networked using a single category cable. This power and data delivery allows for the convergence onto traditional structured cabling infrastructures that are already being utilized in many commercial buildings today. Voice over IP Phones (VoIP) found in most offices today are already being powered using this method, where a single cable is providing both voice (data) and power. With the upcoming ratification of 4-Pair PoE, 802.3BT, the latest IEEE standard will allow up to 100 watts of DC power to be delivered from the power source equipment alongside data transmissions in a single category cable. 
 


 

Cabling and Connectivity Considerations

Cabling must support enough power throughput and efficiency in addition to the heat dissipation capabilities mentioned above.

Connectivity must be robust, durable and provide power headroom for current carrying capacity. Arcing is inevitable with PoE systems, but Legrand’s connectivity locates the last point of contact away from the mated connection, protecting the critical area from spark gap erosion. 50 microinch gold plating of the full mated surfaces and maximum contact area in the full mated position extend the life and performance of the connection. In addition, the connector should have a minimum current carrying capacity of paired traces for structured cabling of 1 amp. Legrand’s connectivity provides up to an additional amp of headroom for superior performance.
 

Increased Power, Increased Heat On The Cabling Infrastructure 

With the upcoming IEEE standard 802.3BT for 4-Pair PoE, the increase to 100 watt power delivery through twisted pair cabling will place additional requirements on the cabling and infrastructure used to support IoT applications.

With an increased power load, heat dissipation must happen efficiently to ensure proper performance of the cable. The ambient temperature of the pathway, as well as cabling temperature ratings must be taken into account.

The TIA recommends that a single cable delivering power and data not exceed an increase of 15° Celsius temperature from the ambient temperature around the cable. The amount of cables bundled together has a direct impact on the temperature rise. When evaluating your category cable, ensure it can provide enough temperature headroom in most cable bundle sizes to not exceed the 15° limit when 100W of power is being delivered.
 

Power And Data Considerations

When deploying IoT applications that utilize twisted pair cable, it’s important to take into consideration the mix of power and data that a device requires. Applications like LED lighting require higher power, but low data bandwidth. In contrast, applications like multi-band and multi-antenna Wireless Access Points require high bandwidth and high power throughput.