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DLVP: The efficiencies of line-voltage in, low-voltage out

DLVP in retail store

A growing number of electrical contractors struggle to find qualified labor for their job sites. Unfortunately, the skilled trades are shrinking, with fewer people seeking official certification each year. And, as seasoned professionals near retirement, the already disproportionate gap on job sites is widening.

This development helped create the demand for an uncomplicated power system that eradicates the need for complex wiring and commissioning, instead using plug-and-play cables that lower labor costs and foster expedited installation. Distributed Low-Voltage Power (DLVP) is a brilliant solution, as it simplifies system installation and reduces costs by changing the power structure of the LED lighting and controls. While a certified electrician is required to install some limited pipe and wire and distributed power modules throughout a building, everything on the outfit side is simple, safe plug-and-play.

We had an opportunity to speak with Chris Andrews, product marketing manager, Eaton Lighting Control Systems, to get a firsthand perspective on the power of DLVP.

What built environments or applications stand to benefit the most from DLVP?

CA: Health care, education, retail, data centers and office spaces are examples of spaces that can benefit from DLVP. We’re currently focused on schools and retail, just because of the innate simplicity of these spaces.

For example, if you’re building a new school, you could easily run line-voltage hidden above hallway ceilings and place a power module in every classroom. Since line-voltage is typically high-voltage (class 1), it would require a certified electrician for installation. But beyond those initial steps, all of the lighting controls in the classroom can be installed by an apprentice, general laborer or — in many cases for school systems — the maintenance staff employed by the school. It’s a great way for schools to save money by using resources they’re already paying for.

In retail, DLVP is best applied in areas of less than 10,000 square feet such as strip mall stores, fast food restaurants, convenience stores or gas stations.

We’re currently working with one of the top five fastest-growing restaurant chains in the nation. They’re planning to open 100 to 150 new restaurants per year. The rate at which electrical contractors are retiring is alarming compared to the unimpressive rate at which the industry is recruiting new apprentices. Compound that with the fact that it can take another three to eight days after installation for the current lighting controls manufacturer to come out and commission the project, and you can imagine how easy it is for projects to get delayed. If you’re opening more than 100 restaurants per year, the faster you get doors open, the faster you start filling cash registers.

What are the benefits of using both AC line-voltage and DC low-voltage?

CA: You can look up almost anywhere in the country and see high-power transmission lines. All of those humongous towers are easily up into the hundreds of kilovolts, and they are as high-voltage as can be safely maintained.

The reason power transmission lines utilize such high-voltage goes back to Ohm’s Law and physics. You want the current as low as possible and the voltage as high as possible to minimize losses and efficiently transmit power across distances.

By design, DLVP is a low-voltage system. Low-voltage is less efficient for transmission for the same load size, in terms of watts, as a high-voltage system. The beauty of DLVP is that rather than distribute low-voltage for the entire building, DLVP uses the line-voltage alternating current to distribute power efficiently throughout the building. Then, in discreet locations distributed throughout the building, DLVP power modules convert from Class 1 high-voltage down to safe, Class 2 low-voltage.

Using line-voltage for power transmission and low-voltage for connectivity makes the entire process simple, extremely fast and electrically efficient. DLVP enables the installer to configure the system at the same time as it is being installed. Most importantly, by using pre-terminated lighting and control cables of standard lengths, DLVP eliminates wiring errors, which directly account for 10 to 30 percent of field support time. The result is a system that installs with 25 to 40 percent fewer man hours than comparable line-voltage systems.

What impact does DLVP have on the cost of installation?

CA: The total installed system cost is reduced by 10 to 20 percent on average. DLVP eliminates many of the materials you may have needed before, like conduits, armored cable and junction boxes. You’re also able to employ someone with a lower labor rate who doesn’t require a Class 1 certification.

In a pre-existing building where you want to make use of low-voltage, the installed cost savings aren’t quite as large, but over time you’ll save on maintenance, which is a major selling point for school systems. Rather than having to use an electrician to troubleshoot, the general maintenance staff can just maintain the lighting in each classroom at a labor rate roughly 40 to 50 percent lower than that of a Class 1 electrician.

Why is lighting an ideal platform for housing this technology?

CA: Lighting is an ideal platform because LEDs inside the light fixtures are inherently direct current devices. Also, the power consumption of light fixtures has decreased considerably in the past 10 years, making them the ideal fit when constrained by the Class 2 definition of not more than 100W. Ten years ago, the typical light fixture in an office might have had three or four T12 fluorescent tubes at 34 watts each, totaling about 136 watts.

Today, for the same amount of light output using DLVP, the light fixtures in the space consume power at about a quarter of previous levels. That means I can connect two light fixtures on a 100-watt, low-voltage circuit. Previously, I wouldn’t have been able to consider low-voltage, because the power level was so high, and we were using technology, filaments, gases and electrodes that all worked well off line-voltage alternating current.

While alternating current may be great for its transformative properties, we’re now questioning whether it’s the only answer. I think we’re starting to see, in our ceilings and walls, that direct current makes a lot of sense.

The Lighting reSource