If you don't know the answer to this question, it's time to get up to speed
Is there a positive relationship between the National Electrical Code (NEC) and the International Energy Conservation Code (IECC) in the area of lighting, or do they compete with each other? The answer to the first question is “maybe.” The answer to the second is “no.”
Known as the most widely adopted electrical code in the United States, the NEC provides rules and regulations for the practical safeguarding of persons and property from hazards arising from the use of electricity. Moreover, it has grown well beyond domestic borders and is now used in a number of other countries. Considered a “living” document, the NEC is updated on a three-year cycle. For electrical installation of conductors, raceways, equipment, overcurrent devices, and grounding systems in support of lighting systems, the use of the NEC is appropriate and mandatory in the vast majority of installations.
In the design of energy-efficient buildings, the IECC offers a code development process and an international forum for energy professionals to discuss the latest performance and prescriptive code requirements. Internationally, code officials recognize the need for a modern, up-to-date energy conservation code that addresses the design of energy-efficient building envelopes and the installation of energy-efficient mechanical, lighting, and power systems through requirements that emphasize performance.
The IECC is designed to meet the needs of energy-efficient buildings through model code regulations, which hopefully result in the optimal use of fossil fuel and renewable resources.
Like the NEC, the IECC is available for adoption by jurisdictions internationally. Its use within a governmental jurisdiction must be through adoption by reference, in accordance with proceedings establishing the jurisdiction's laws. At the time of adoption, jurisdictions often insert the appropriate information in provisions requiring the addition of specific local information.
But how do these two codes differ in the area of lighting? Are there similarities in some areas, or are they drastically different? Let's take a closer look to see how these two important codes address the topic of lighting.
The 2005 NEC. The NEC lists requirements for the switching of lighting outlets in dwelling units in 210.70. Sec. 210.70 also includes the switching of lighting outlets in guest rooms and guest suites of hotel and motels, and in attics and under floor spaces containing equipment that requires servicing. In addition, 110.26(D) and 110.34(D) require illumination for the working spaces about electrical equipment.
However, what may become a challenge for electrical designers is the application of 410.73(G), which calls for a disconnecting means at each luminaire. The effective date of this requirement is January 1, 2008.
The challenge could be how to apply the disconnecting means (when required) to luminaires served by more than one ballast (which is an IECC requirement for light reduction controls). Conversely, from the IECC perspective, a challenge may arise when the luminaires feature three or four lamps and are supplied by only one ballast.
The 2003 IECC. Sec. 805 of this code covers lighting systems controls, the connection of ballasts, the maximum lighting power for interior applications, and minimum acceptable lighting equipment for exterior applications. This section does not apply to dwelling units. It is intended for commercial buildings only.
The IECC states that each area enclosed by walls or floor-to-ceiling partitions shall have at least one manual control for the lighting serving that area. The required controls shall be located within the area served by the controls or be a remote switch that identifies the lights served and indicates their status.
There are two exceptions to this requirement. In areas designated as security or emergency areas that must be continuously lighted, a switch is not required. Also, lighting in stairways or corridors that are elements of the means of egress is not required to have a switch installed.
Light reduction controls are also required for the areas enclosed by walls or floor-to-ceiling partitions. These areas shall have the capability of reducing lighting levels to 50% of the maximum light level. The reduction shall also be in a reasonably uniform pattern. This may be the most important requirement of the IECC with respect to lighting.
There are four choices listed to comply with this requirement:
Control all lamps or luminaires;
Dual switching of alternate rows of luminaires, alternate luminaires, or alternate lamps;
Switching the middle lamp of the luminaire independently of the outer lamps; or
Switching each luminaire or each lamp independently.
Light reduction controls are not required in:
Areas that have only one luminaire;
Areas that are controlled by an occupant-sensing device;
Corridors, storerooms, restrooms or public lobbies;
Spaces that use less than 0.6 watts per square foot (or 6.5 watts per square meter).
Automatic lighting shutoff is required for buildings larger than 5,000 square feet (465 square meters). This shall be accomplished by use of an automatic control device, which will function on either one of the following:
A scheduled basis, using time-of-day, with an independent program schedule that controls interior lighting in areas not exceeding 25,000 square feet (2,323 square meters) and on not more than one floor; or
An unscheduled basis by occupant intervention.
Where an automatic time-switch control device is installed, it shall incorporate an override switching device that:
Is readily accessible;
Is located so that a person using the device can see the light or the areas controlled by the switch, or so that the area being lit is annunciated.
Is manually operable.
Allows the lighting to remain on for no more than 2 hours when an override is initiated.
Controls an area not exceeding 5,000 square feet (465 square meters).
Exterior lighting controls, whether automatic or photocell action, shall be provided for all exterior lighting not intended for 24-hour operation. Automatic time switches shall have a combination seven-day and seasonal daylight program schedule adjustment, and a minimum 4-hour power backup.
When it comes to the installation of luminaires, the IECC has a requirement for “tandem” wiring. The following luminaires shall be “tandem” wired:
Fluorescent luminaires equipped with one, three, or odd-numbered lamp configurations, which are recess mounted within 10 feet (3,048 mm) center-to-center of each other.
Fluorescent luminaires equipped with one, three, or odd-numbered lamp configurations, which are pendant- or surface-mounted within 1 foot (305 mm) edge-to-edge of each other.
Guestrooms in hotels, motels, boarding houses or similar buildings, shall have at least one master switch at the main entry door that controls all permanently wired luminaires and switched receptacles, except those located in the bathrooms(s). These sites shall have a control at the entry into each room or at the primary entry to the suite that meets these requirements.
In the end. The bottom line is the NEC and the IECC are setup to address different subject matter.
The purpose of the NEC is the practical safeguarding of persons and property from hazards arising from the use of electricity. The intent of the IECC is to regulate the design of building envelopes for adequate thermal resistance and low air leakage and the design and selection of mechanical, electrical, service water-heating, and illumination systems and equipment that enable effective use of energy in new building construction. Therefore, it's in your best interest to stay abreast of the latest changes implemented in both of these important industry codes.
Owen is the owner and president of National Code Seminars in Pelham, Ala.