Lighting industry journalist and educator Craig DiLouie, LC, CLCP recently had the opportunity to interview David Buerer, Director of Product Management, Leviton Manufacturing Co., Inc. for an article about plug load control, which will be published in the October 2021 issue of tED Magazine, the official publication of the NAED. Transcript follows.
DiLouie: What is plug load control, and what benefits are derived from it? Why should electrical distributors care about or invest in promoting this category?
Buerer: In this modern age, it feels like we’re constantly getting more and more gadgets that require wall receptacle power. While crowded wall outlets are increasingly common, what’s less understood is the potential to save energy by controlling what we’re plugging in. One simple and efficient way to improve energy efficiency is Receptacle Control, also known as Plug Load Control, which automatically de-energizes plug loads when a space is vacated.
Plug loads include devices that plug into a standard electrical outlet, often called “standby” or “vampire” loads. Products not in use or on standby account for as much as 25 percent of total electrical consumption in commercial buildings. These products typically still draw power even in an off state. Examples include:
- Task lighting
- Cell phone chargers
- Personal fans/heaters
- A/V equipment
- Small appliances (toasters, coffee makers)
Any electronic devices that can be switched off at night without causing harmful consequences are perfect candidates for plug load control.
It’s not just smart, it’s the code. Energy codes require Receptacle Control or Plug Load Control. Both ASHRAE Standard 90.1 2010/2013/2016/2019 and 2019 Title 24, Part 6 require controlled receptacles to have the same automatic shutoff function as lighting using either occupancy sensing or schedule-based control. Plug-in strips and devices cannot be used for code compliance.
The National Electrical Code also requires all 15A and 20A, 125V receptacles that are automatically controlled to be marked with a specific symbol and the word “CONTROLLED” on the receptacle.
DiLouie: What are the options for controlling plug loads?
Occupancy Sensing Based Receptacle Control: Utilize a common occupancy sensor to provide control of both lighting and plug loads. This allows users to monitor a space’s state of occupancy and will energize and de-energize a controlled receptacle based on occupancy. Leviton offers Smart Wallbox Sensors and Leviton Occupancy Sensors to address this need.
Schedule-Based Sensing Control: Schedule lighting to automatically turn on and off and plug loads to energize and de-energize based on time of day. Leviton options include the GreenMAX DRC Room Control System, EZ-MAX Plus and GreenMAX Relay Panels.
DiLouie: What are the advantages of controlling plug loads with a lighting control system?
Buerer: Plug loads are automatically de-energized when the lighting control system senses that a space is not occupied. Users can also schedule plug loads to automatically be de-energized based on time of day. In most lighting control systems, plug loads can be taught to follow occupancy patterns of the room even if the lights are off. You can do this by indicating that the occupancy loads should never be controlled by the switch and ensuring that the plug loads are always in “auto on” mode even if the lights are in “manual on” mode.
DiLouie: What types of equipment are required to add on plug load control capability to a lighting control system?
Buerer: The implementation strategy varies based on what type of technology you are deploying in the room.
- If your solution are wallbox sensors, then it can be as simple as adding a second wallbox sensor control receptacle.
- If your solution is ceiling sensors and power packs, then adding a second power-pack in auto-on mode allows you to control the receptacles
- If the technology is more of a system, then you’ll be adding a wireless controlled receptacle, smart pack, wireless power pack, or the like to gain receptacle control
One of the simplest deployments is to use a wallbox room controller like Leviton’s DL057 for your main lighting, a ZSC15 sensor for occupancy detection, and a ZSTLR controlled receptacle for receptacle control. You can add additional switch zones by using Leviton’s ZS057 wallbox switches or LU107 wireless controlled power packs.
DiLouie: What are the advantages of either wiring or going wireless with communication?
Buerer: Wireless solutions eliminate the pain point of pulling new wires to meet energy code requirements for receptacle control or plug load control. like the Leviton Zigbee 3.0 Controlled Receptacle requires no additional control wiring, making it easy to install with little to no interruption to operations. This makes it ideal for both retrofits and new construction. Zigbee uses mesh networking technology to provide quick, reliable, and secure communication.
DiLouie: When proposing integrating plug load control into a lighting upgrade, what approaches are used to estimate future energy savings?
Buerer: If you don’t have access to a plug load energy savings calculator, you can estimate savings based on the difference between keeping plug load devices on 24/7 versus the number of hours that these devices would be turned off after hours and on the weekends. Multiply these hours by the average kWh rate to calculate your savings.
DiLouie: What is an ideal sales pitch for plug load control?
Buerer: Know your energy code and NEC requirements and understand how to calculate estimated energy savings.
Save money by turning off power to things that are not needed when no one is in the room.
DiLouie: Are there any tradeoffs or pitfalls that must be mitigated, such as ensuring users are educated, or putting the wrong equipment on controlled receptacles?
Buerer: Users should always be educated about new technologies installed in a space to eliminate potential complaints and unnecessary calls about equipment not working correctly. The education should also include a list of appropriate electronic devices that can be switched off at night without causing harmful consequences that make it perfect candidates for plug load control.
Installations should always consider whether the application requires a single or duplex controlled receptacle and ensure that the appropriate components are wired correctly and that the appropriate electronic devices are plugged in.