Only 50 or so years ago, lighting control was simple. Most projects included a time clock for outdoor lighting. If the engineer felt like getting fancy, a photocell was added. If more than a couple of circuits were involved, a lighting contactor was contacted. 

Interior lighting controls were most often simple local switching. If more advanced controls were needed, a few relay-based systems were available, such as Bryant, GE, Pyramid/Remcon, Sierra and Touch Plate. These systems were fairly simple to control, with hard wiring between remote switches and relay panels. 

The lighting controls described above were mostly designed to meet customers’ requirements. Saving money on the electric bill was a concern, but the ability to turn lights off that were not needed was voluntary. Then, the 1973 oil crisis started a series of events leading to extreme energy shortages in much of the western world. California responded in 1975 by creating the California Energy Commission to address energy issues. 

California leads the way

California’s Title 24 lighting code was first enacted in 1978 as part of the California Energy Code, which regulates energy efficiency standards for buildings. I am writing about California’s codes as they most often lead the rest of the nation when it comes to saving energy through lighting control. Many of today’s lighting control system features have been inspired and shaped by California’s Title 24.

Living and working in California has made me very aware of our energy codes. However, some of my customers are not in California. I have learned from them that not every state has adopted the same codes. Some have, and others may soon follow, so it is important that most electrical estimators understand energy-saving lighting control systems. 

Now, with a few exceptions, California requires that lighting fixtures in new construction and some remodels must be automatically turned off or dimmed, depending on where they are located. Some of the exceptions are egress lighting, floor, wall, window and case displays, art displays and special effects lighting. In most of these spaces, Title 24 requires manual controls, with on, off and optional dimming control. These areas must be independently controlled, each with their own switch. 

Sensors and controls

Let’s take a look at how California’s Title 24, Part 6, mandatory controls accomplish some of the various functions required for commercial buildings. Automatic shutoff devices are required to turn off or reduce lighting in most areas when vacated. This is most often accomplished with motion or vacancy sensors. From an installation perspective, these devices are the same. 

Functionally, motion sensors are completely hands free, while vacancy sensors require manual activation but automatically turn off the lights after motion is not detected for a set period. These devices are available as wall- and ceiling-mounted. The wall-mounted devices are fully functional by themselves and are most often used in smaller rooms, such as an office for one or two people. Ceiling-mounted devices are used for areas such as large offices, conference rooms and large open spaces. Additionally, areas with windows may require installing daylight sensors, which dim or reduce the lighting based on the available sunlight. 

Most ceiling-mounted devices do not handle line voltages, such as 120V or 277V. A power pack, or several, may be required for the installation. These power packs are almost never shown on the drawings. It is up to you to add them to the design and include them in your estimate. The power pack is essentially a relay between the low-voltage sensors and the line voltage circuit. For larger rooms, several power packs can be connected to one or more sensors, allowing for on, off and dimming control from multiple locations.

Another function required by California’s Title 24 is the ability to turn off a portion of the 120V receptacles in areas such as offices, conference rooms and lobbies. This is accomplished by linking one or more receptacle circuits to the motion or vacancy sensors for the area. Depending on which manufacturer’s system is being used, this requires another device such as a room or receptacle controller. Controlled receptacles must be marked to indicate they are controlled. Most of the specifications I read require the marking to be on the receptacle.

The California-style lighting control systems requirements can be complex. I will admit, when this code first came out, I was baffled. Even the engineers could not design one of these systems. As it turned out, the lighting control manufacturers’ representatives are the best source of information.

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