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The use of LED (light-emitting diode) technology reduces the power necessary for lighting. Various studies have explored the efficiency of PoE LED connected lighting systems, and how the energy use compares to either AC-based LED lighting or AC-based fluorescent lighting. After extensive testing of our nLUMINAIRE products, we have found that our PoE connected lighting system can be up to 40% more efficient than AC-based LED lighting, and up to 95% more efficient than AC-based fluorescent lighting, depending on parameters such as cable category or length, among others. These energy savings are undoubtedly substantial, and we are dedicated to being a frontrunner in the field of PoE connected lighting systems to create sustainable, energy-saving lighting solutions. Developments in PoE technology have increased, and are continuing to increase, the amount of power delivered over a single cable. LED usage and PoE connected lighting technology combine for optimized energy savings. Well-designed systems such as our nLUMINAIRE technology provide further savings and are essential for the future progression of connected lighting systems.

Our nLUMINAIRE system combines the best of smart technology in a PoE networked lighting control solution. Our suite of smart devices works fluently with our nManager software to offer an ideal connected lighting solution. Part of a system’s efficacy is its ease of installation and its overall performance in real-world applications. Studies focusing on the components of connected lighting systems and optimizing a system’s performance help the industry push PoE lighting technology further.

To improve the efficiency of PoE connected lighting systems, we need to consider the system’s design and consider any aspects that may affect cable energy performance, such as conductor DC resistance as estimated by the AWG or installation practices. https://www.energy.gov/sites/default/files/2018/11/f57/cls_poe-cable-pt2.pdf In a recent study, the US DOE found that when the cable length is 50 m or less, the power loss does not exceed 5%, establishing that the guidance in ANSI C137.3-2017 is effective.We will investigate the details of these findings and those determined in the follow-up study.

In the second part of the study completed by the US DOE, further exploration of power losses in PoE connected lighting systems highlighted key aspects necessary to optimize power and data transference. The study delved into how cable selection and installation practices impact the efficiency of a PoE system and the efficacy of the ANSI C137.3 guidance. In this exploratory study, the testing set-up was comprised of a PoE switch, luminaires, and a reference meter for testing various cable models and designs. Let’s explore the three focus areas for this study: cable selection, bundle testing, and bend testing.

Focus Area 1: Cable Selection

The first focus area of cable selection is essentially a continuation of the first exploratory study completed by the US DOE to determine the effectiveness of the ANSI C137.3 guidance. The second study included cables that were acquired but not used in part 1 of the study due to compatibility problems, as well as an additional unshielded 24 AWG Category 5e cable.

In the first cable configuration to be tested, short (1.5 m) and long (49 m) cables were field-terminated using RJ45 plugs. Short and long unterminated cables were used with .5 m patch cords in the second configuration. Finally, the third configuration used a jack-terminated cable (45 m) with plug-terminated patch cords (2.1 m).

ANSI C137.3 includes the recommendation of limiting input power to less than 55 W for 4-pair PoE at 24 AWG. Power losses varied slightly with differences in AWG as larger AWG corresponds to greater DCR per unit length; this results in greater I2R. Further testing showed that the 44 W luminaire consistently stayed below 5% loss (3.0%-3.7%) for all tested cable models at 49m.

Focus Area 2: Cable Bundling

Testing on bundled cables demonstrated the impact of temperature variation on power loss. The two configurations tested included cables loose in a cable tray, which was used to establish a baseline, and cables bundled in a conduit with a fill ratio of ≥ 40%. Input and output power were recorded at 5 min intervals for 16 hours, providing much valuable data.

Focus Area 3: Cable Bending

The study also included bend testing to determine the effect of multiple small-radius bends on power loss. As you might expect, excessive bending could damage the insulation, affect connectivity, and even increase DCR unbalance. This focus area considered real-world applications of PoE lighting systems in realistic installment scenarios. A baseline test was done using loose cables. Comparison tests included wrapping the cable around a metal shelving unit 24 times, creating 90o angles at each of the bends. Each test in this focus area used a 44 W luminaire and a range of parameters such as cable diameter, AWG, shielding, and category. 

Summary of Findings

As previously mentioned, variations in cable installation practices can include cable bending, bundling, and the use of conduits. These variations were not found to substantially impact cable power loss if the ambient temperature of the environment is under 30^o C. However, environments with ambient temperatures above 30^o C saw increased power losses. This increase results from a higher conductor DC resistance. The real-world setting of a system must be considered when trying to optimize the performance of a PoE connected lighting system. As more powered devices that reach 90 W are introduced, we anticipate more impact from installation practices. Additional energy losses in PoE cables may become apparent as the power limit for powered devices increases.  

According to Part 2 of the US DOE study, cable losses decrease as the conductor diameter increases, with smaller AWG. However, variations in other characteristics did not produce an appreciable difference in power loss. However, this does not necessarily mean that specific parameters do not affect loss, given that the cable set used for the study was limited. As technology advances and connected lighting systems gain more traction, additional studies will reveal more detailed findings.

The overall takeaway is that the guidance offered by ANSI C137.3 is consistently effective in limiting the power loss to 5% of PSE output, given that the cable length does not surpass 50m. Additionally, with room temperatures below 30^o C and the usage of 44 W luminaires, neither bundling nor bending substantially impacts power loss.

What’s next?

Various components must work seamlessly together for an optimized, high-performing, energy-saving connected lighting system. With nearly countless variables within each component, numerous configurations and product options exist in the field, and more are being developed. The nLUMINAIRE system combines the fields of smart technology from IoT and PoE to AI and data analysis to offer an energy-saving, sustainable lighting solution. Through developing new technology and testing our innovations, we will continue to challenge the boundaries and expectations of PoE connected lighting systems and simplify the future of lighting.