MH Controls Corner: PoE Lighting and Its Challenges

This article was written by Mike Bogomolov, our Controls Engineering Supervisor. Mike can be reached at 720.904.8537 or mike@mhlighting.com.

The inevitable next frontier for the commercial lighting industry is controls integrated into light fixtures. It makes sense, as the controls industry has claimed an ever increasing footprint in lighting design, and both lighting and controls must coexist. Why not wrap it all up into a single package? In doing so, we can consolidate on delivery, installation, and maintenance of a lighting package for any given project, all of which lead to cost savings for the end user which is usually a main objective. Few options in the foreseeable future stand to provide this level of integration more than the concept of PoE (Power over Ethernet) lighting. However, as we all know, no concept goes to market without a slew of inherent problems that must first be addressed.

The idea of a PoE lighting solution is certainly an enticing one with numerous benefits that make it a hard concept to ignore. Powering fixtures off of low voltage DC power would allow for any IT professional to maintain the lighting in a space much like they would a Wi-Fi access port. The ability to address fixtures individually would allow for reconfiguration of lighting in a space without having to ever touch the fixtures. And, perhaps the icing on the cake that might give this solution the boost that it really needs is the world of data and data collection…the world of IoT (Internet of Things). Having a network connection to each fixture in a space means that light fixtures—the one item that covers more area of any given building outside of the floor, walls, and the ceiling—can now be integrated with sensors and other data gathering devices powered and monitored by the same backbone that supports the lighting in the space. Agreeably, it just makes sense, but will come with its own set of challenges since all integration requires a great level of timing and coordination.

One of the challenges will be getting the lighting industry to accept, and then turn their fixture production to support low power DC as a power source. Performance using this power source has to meet or exceed the performance levels that govern today’s commercial LED lighting sources. Can a high output LED really be powered off of PoE and still have the ability to provide the lumens required? And, if so, how many fixtures can we hang off of a single patch cable? That is going to be the balance that needs to be monitored and maintained as the concept of PoE moves forward. Today, applications, such as warehouses and gymnasiums, and site lighting applications, such as parking lots, are not even on the horizon. Current IEEE limitations on CAT5 wire are capped at 960mA and 100W, with only 71W making it to the device. That limits room for data transmission with all four pairs pushing power. Fixture manufacturers will have to push the efficacy of their fixtures until there is a sensible approach to the fixture per PoE port ratio in most, if not all, lighting applications, from classrooms and offices, to the big box stores, where data collection would be of most value.

The other side of this, of course, is the power source and data management side. PoE fixtures will require a DC power source, and the cable to supply that power source to the fixture, along with any data required for control of the fixtures, as well as any monitoring of power draw additional data. Today’s network switches, along with cables, are mainly set up for data transmission. Data, as well as the switches, are expensive. If every fixture required its own PoE port, we would need an excessive amount of switches, the cables to support individual home runs, and the space allocated in each building to house all of those switches and cables. Architectural floorplans would suddenly need more IT rooms than they would janitor closets! With PoE switches costing somewhere in the neighborhood of $7,000 for 48 ports, we would be looking at $150 per fixture from port allocation alone, not taking into account the cost of patch cable, as well as the space required to house those ports. And, of course, there’s the cost of the fixture itself. That is a heavy price to pay, and perhaps one of the leading reasons that might be deterring the fixture manufacturers from exploring support of the PoE lighting infrastructure today.

In order for things to really come together, we will need to witness efficacy of fixtures increasing (and that also has its limits), as well as provisions for data collection integration into fixtures to take to market. The price of switches would have to drop drastically, and perhaps a lighting-specific market for PoE switches and cables will have to emerge. Data collection markets will also have to do their part in exploring fixture-based data collection methods, and play a role in funding this frontier. Agreeably, there is much to look forward to in the world of PoE lighting, but collaboration and timing will be key in assuring this concept truly moves forward.

Whenever you have a technical controls question on any project or application, simply email piccontrols@mhlighting.com. This email address is monitored by our entire controls team. During our normal business hours, we are committed to a four-hour response time for all emails sent to this email address!