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Industry Insights

CTD: Connecting Low Voltage PoE LED Lighting

Wednesday, September 21, 2016 | by Rudy Montgelas

Did you know that to save energy and provide enhanced occupant experiences, lighting systems in commercial buildings are emerging that utilize energy saving LED troffers powered by low voltage power over Ethernet (PoE) networks?  There is a significantly reduced operating energy cost and higher reliability with the LEDs compared to incandescent or fluorescent lights.  In addition, the safety and efficiency of DC power, in conjunction with the ability to converge the data over twisted pair cabling, is a compelling reason why this technology is being considered.
 

What’s Low voltage LED lighting?
 

LEDs (light Emitting Diodes) are efficient and compact semiconductor devices that give off light (photons) when a direct electrical current of sufficient voltage is applied to the (P-N) junction of the device.  
 


 

LED technology has been heavily under research for automobiles for many years and this research has lead to significant advances in LED materials and reliability.  Because LEDs do not have filaments like common household electrical light bulbs, they don’t generate nearly as much heat as the filament lamps.  Also, they use only a fraction of the energy to generate the equivalent amount of light from both incandescent and fluorescent bulbs. 
 

Why consider low voltage LED lighting systems?
 

When you head to the hardware store today, you’ll hardly see filament light bulbs anymore.  Those bulbs are rapidly being replaced by LED bulbs and the prices are dropping significantly as more LEDs light bulbs are being produced. Even the US Department of Energy is promoting the effort to replace incandescent light bulbs with LED bulbs and has some interesting statistics on energy savings and LED lighting at their website 1.  

 


 

This low voltage LED lighting technology is permeating into the commercial office space as well.  One of the key reasons is the advantages afforded by using low voltage (about 45 to 60 volts DC) PoE based power, cabling and connectivity to the lights at 60 watts.  PoE can now power LED lights over low voltage four pair twisted copper cabling rather than having to use conventional high voltage 120VAC copper cabling.  In a sense, Power, Lighting and Data can now converged over the same cable.  One might think of it as PLD convergence.
 

What should I think about when considering a PLD network infrastructure?
 

Cisco recently released a Catalyst® 3850 (UPoE) switch on the market that delivers DC PoE power at 60 watts.  This switch can be used to power LED lighting fixtures (troffers) installed in the raised ceilings of office buildings. 
 

 



Recently, Legrand teamed up with Platformatics, who makes the software/firmware and the system controllers for the LED troffers, Superior Essex, with their PoE optimized PowerWise cabling, and Cisco’s with their 3850 UPoE switches, to produce a low voltage UPoE LED lighting installation solution in Fishers Indiana.2
 
The LED lights in the building have color tune ability and the intensity is adjustable through a user interface application which resides on wireless mobile devices and PCs.  The Platformatics Area Controllers provide security and application programs to handle control and manage the LED troffers.  Wall switches, and temperature and occupancy sensors converge the temperature, occupancy and day lighting harvesting data onto the single PoE cable integrally connected to the system.
 



When planning and installing such a LED lighting system, it is important for the infrastructure designers and installers to think about some of the following considerations:

  • Cabling distance runs and number of copper cables in a bundle contributing to power and signal loss as well as heat generation.
  • Centralized or Decentralized PoE  
  • Proper heat dissipation for the UPoE switches
  • The use of copper UTP cables capable of handling the PoE voltages and currents required by the LED lights such as Superior Essex’s PowerWise™ cabling is recommended which has the industry’s lowest loss and heat rise for PoE applications

Catalyst is a registered trademark of Cisco Systems.

 

  • The selection of robust copper RJ-45 jacks and plugs capable of carrying 1.5 amps of PoE power or more, such as Legrand’s Clarity series CAT5E or CAT6A jacks that do not suffer from contact signal degradation due to “spark gap” erosion when disconnected

Legrand’s HDJ series patch panels offer hybrid modularity and connection flexibility for quick and easy multimedia insertions into a high density patch panel footprint. So, the 24 and 48-port HDJ series angled patch panels, CAT5E Jacks and 2-port surface mount boxes were ideal to interconnect the switches and the LED ceiling troffers.  More importantly, the Clarity 5E jacks are designed with additional power and data “headroom” to support the distributed power demands for the LED lights while at the same time assuring up to 10 gigabit per second error-free data connections.
 

 

Summary

Future buildings will continue to require the need for more advanced, converged power, lighting and data solutions. This will include the support for high speed data communications, lighting and power delivery through a sophisticated network infrastructure for its occupants.2 Converged power, LED Lighting and data, over carefully selected PoE DC low voltage cabling and connectivity components, can offer potentially significant energy savings, features and costs for these office buildings of the future.  This technology may even possibly have potential applications for residential and smart home applications in the future as well.  
Stay tuned for more exciting developments in commercial LED lighting as the technology evolves through the Legrand ELIoT initiative, the addition of Pinnacle Lighting Systems to the Legrand family and Legrand’s partnership with Cisco in the Digital Ceiling Platform.3
 

References:

1 US Department of Energy Website: http://go.legrand.us/e/84502/energysaver-led-lighting/5s3n47/162460196
2 “Lighting the Way Through innovation at Launch Fishers with Digital Ceiling PoE LED Solutions” Legrand White Paper - 2016
3 Press releases on Legrand’s Digital Ceiling Initiative