What's Inside?
When designing the lighting for a space, there is always a debate concerning what lighting control system is best, and a large part of this involves cost. Owners want a simple, cost-effective solution that meets their needs and the building code requirements.
Traditionally, this was accomplished by timeclocks, contactors, switches and other standard lighting control equipment found at a local distributor or electrical supply house. Recently, the need for advanced lighting controls, including dimming, have complicated this issue.
Is it better to stay with the traditional timeclock, contactors and switches, or is it time to make the switch to a lighting control panel or even an architectural dimming panel? Some consider lighting control and dimming panels expensive, complicated, and not worth the trouble.
Dialectic will examine lighting control systems to compare their benefits, drawbacks, and approximate cost by looking at a typical installation and some common systems.
Additionally, we will provide an overview for those new to lighting controls, explore why controls have become more complicated, and examine common issues encountered with dimming different load types.
First, to enhance reader understanding, an explanation of the following terms:
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Lighting controls have become increasingly important and complicated. This can be attributed to evolving energy codes, an increased desire for “smart” buildings with intelligent control systems and changing lighting sources with demanding dimming needs.
A toggle switch at the door is no longer acceptable to building officials or occupants, who require a higher level of lighting control design. For the past 20 years, energy codes have been implemented across the United States.
In the beginning, energy codes were focused on restricting the amount of wattage installed. For the past 10 years, there have been increased requirements for manual and automatic lighting controls to further reduce energy use.
Below is a short summary of lighting control requirements commonly required by energy codes.
Manual controls are initiated by the occupant. They give the ability to adjust lighting in the space with the assumption that occupants will turn off lighting they do not need or want and consume less energy.
Wiring for inboard/outboard switching Inboard/outboard switching is a common way of providing multilevel lighting control.
Depending on the space type and load, general lighting within a space is usually required to be multilevel. While older codes allowed 50-50 or bilevel switching, newer codes may require dimming under certain circumstances.
Each space is required to have individual controls so the occupant can control the lighting. The controls have to be within the space or placed remotely with some way of indicating the on/off status of the lighting.
Automatic controls work without the occupant initiating them, with the assumption that there is some lighting usually left on. By providing automatic controls to turn off or dim unnecessary lighting, less energy will be consumed.
All energy codes allow or require the occupant to have the ability to override automatic controls for a limited amount of time.
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Wall switch occupancy sensor
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Digital timeclock
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All lighting is required to be connected to automatic shut-off controls. This can be accomplished by a timeclock or occupancy/vacancy sensors.
Depending on the space type and wattage, general lighting near a window or skylight may be required to automatically turn off or dim in response to available daylight.
Secondary Sidelit Daylit Zone Diagram 1
2016 Nonresidential Compliance Manual, Page 5-31
CALIFORNIA ENERGY COMMISSION © 2018 State of California
Different dimming standards are required depending on the fixture type. All dimmers have specific considerations which must be followed for them to perform properly, and there can still be compatibility issues which must be addressed in the field.
Below are the three most common dimming types and their design considerations.
Wiring for typical line voltage wall dimmer Line voltage dimmers include incandescent, MLV (magnetic low voltage) and ELV (electronic low voltage) dimmers. They are wired the same way, but the resistive dimming device is different for each.
Wiring for typical 0-10V wall dimmer
© 2018 Acuity Brands Lighting, Inc. All rights reserved.
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Track head with electronic Magnetic low voltage power supply |
Magnetic low voltage power supply |
We will use an example space with common control requirements, and compare the differences in equipment, installed costs, setup, use, benefits and drawbacks between four common dimming systems.
A retail sales floor has been chosen, but many of the issues encountered would also occur for restaurants or offices. The back of house spaces will not be addressed to simplify the comparison.
The lighting in the space has both ELV and 0-10V dimming requirements. Automatic controls are required to shut off all lighting at the end of the day and dim the daylight zone near the window.
Manual controls are required to:
| Timeclock and Contactors | Smart Breaker Panel | Relay Panel w. 0-10V Dimming | Architectural Dimming Panel |
We will compare four systems: timeclock and contactors, a smart breaker panel, a relay panel with 0-10V dimming, and an architectural dimming panel. All systems will provide the same control functions.
Light fixture schedule
For each system we have developed a bill of material, switchbank elevation, riser diagram and one-line control diagram. Because we have not included the equipment that is the same for each installation, the calculated cost can only compare costs differences between the systems, not the total costs of each system.
Setup is performed by the electrical contractor and is limited to setting the timeclock on and off schedule. This could also be done by the occupant.
Occupants adjust light levels as needed with the local switches. They can override the timeclock for up to two hours with the override switches and adjust the lighting fixtures in the daylight zone with the remote.
We have assumed that this system can be set up by the electrical contractor and added additional labor to the cost estimate to account for this. Setup requires setting the on or off status of the breakers based on triggers from the associated low voltage switches.
Occupants can turn lights on and off using the low voltage switches. These can also be programmed to override the timeclock, so separate timeclock override switches are not required. Dimming requires separate dimmers, and the daylight zone is adjusted using the remote.
We have assumed that this system can be set up by the electrical contractor and added additional labor to the cost estimate to account for this. Setup requires setting the on or off status of all lighting, the dim level of dimmed 0-10V lighting, and the dimming response of the photocell.
Occupants turn lights on and off, adjust the dimming level of 0-10V fixtures, override the timeclock and adjust the daylight zone using the low voltage control switches. Dimming the ELV fixtures requires use of local dimmer switches.
We have assumed that setup will require a site visit by a factory representative and added additional labor to the cost estimate to account for this. Setup requires setting the on or off status of all lighting, the dim level of dimmed 0-10V and ELV lighting, and the dimming response of the photocell.
Occupants control all functions of the lighting control system through the low voltage switches.
Each system has its own benefits and drawbacks and, depending on the needs of the client, any one could be considered the correct choice. Below are some reasons why an owner may choose each system.
They require an inexpensive system, though owners may not realize that the least expensive option may be a basic relay panel or some other system depending on their needs. Scenes are not needed at different times of the day or for special occasions.
If owners do require a special scene, it is acceptable to create that scene manually and then adjust back regular settings manually when done. Owners do not have the facilities management staff available to modify the programming of a more complicated system.
Space in the electrical room is at a premium and eliminating as much additional wall mounted equipment as possible is required. Lighting control is limited to switching scenes of large groups of fixtures, for instance, if a client has a large space that needs to switch lighting in three groups such as millwork, downlights, and signage.
Smart breaker panels are popular with many big box retailers, and commercial and industrial facilities. While this solution was more expensive in our example, in the correct application it can provide a cost savings.
If the owners are building a new facility and will already be purchasing new panelboards, there could be a cost savings.
Dimming is required, and most of it is 0-10V. If this system is used, it is beneficial to select fixtures that have 0-10V dimming over other dimming types during the lighting design. Switching scenes are required at different times of day and for special occasions.
If a lighting scene is created manually for a special occasion, lighting must return to the regularly scheduled scene the next scheduled occurrence. Owners have the facilities staff available to modify the relay panel as needed.
Many relay panel manufacturers do offer remote programming. If the relay panel is connected to the internet or provided with a telephone line connection, trained staff are available to dial into the system and make any changes desired with clients while they are on the phone.
Multiple types of dimming are required and they must all be controlled by an integrated system in order to set scenes. Specific scenes are required and these must be determined and programmed at the time of commissioning.
For example, high-end retailers with windows facing busy streets may require specific scenes for store open, daytime, stocking, night, and special events. The clients are comfortable using an architectural dimming panel and facilities staff are available to modify it or know how to contact with the manufacturer if changes are required.
Other lighting control systems are available in addition to those listed. For example, distributed controls have gained popularity and offer many advantages for some projects.
Dialectic’s team of design engineers are always happy to help answer your questions. Contact us today.