Luminaires and Lighting Systems

Chapter 4 of the NEC, Equipment for General Use, is concerned with pieces of equipment, not with the wiring methods that bring power to them (which are covered in Chapter 3 of the Code).

Article 410 - Luminaires, Lampholders, and Lamps

Article 410 covers line-voltage lighting systems. That is, our common 120-volt, 240-volt, and 277-volt light fixture installations. In particular, it covers luminaires (also called lighting fixtures), lampholders, pendants, receptacles, rosettes, incandescent filament lamps, arc lamps, electric-discharge lamps, and the wiring and equipment that form such items, as well as their installation [410.1].

Let’s begin by clarifying the term, luminaire. As indicated, it is basically another name for “lighting fixture,” but when discussing a book of specific and precise engineering and construction requirements such as the National Electrical Code, it is necessary that we understand the full meanings of the words used. In Article 100, it is defined as follows:

Luminaire. A complete lighting unit consisting of a light source such as a lamp or lamps, together with the parts designed to position the light source and connect it to the power supply. It may also include parts to protect the light source or the ballast or to distribute the light. A lampholder itself is not a luminaire.  

In the 2008 Code, this definition was revised to clarify that a luminaire can include parts for protection of components and parts for light distribution and to specify that an individual lampholder is not a luminaire.  

General Requirements

The most general requirements for lighting system installations are covered in the earliest sections of Article 410. They include the following:

•       No live parts may be normally exposed on any luminaire (including portable luminaires), lampholder, or lamp. An exception is made for cleat-type lampholders, provided they are at least 8 feet above the floor [410.5].
•      All luminaires and lampholders must be listed. This requirement means that they must be “included in a list published by an organization that is acceptable to the authority having jurisdiction . . . and whose listing states that either the equipment, material, or service meets appropriate designated standards or has been tested and found suitable for a specified purpose.” (See the definition in Article 100.) In practice, this requirement (in the United States, anyway) is accomplished by the product being listed by Underwriters Laboratories. Any fixture that is not clearly listed should NOT be installed.

Clothes Closets

A critical portion of Article 410 concerns clothes closets. This area is one that has been prone to problems. Flammable items such as paper and cloth are frequently put into closets and are often crammed into place by hurried individuals. This situation, combined with the high heat of many light sources, has led to numerous fires. For just this reason, the NEC contains very specific requirements for lighting in clothes closets.

The installation of various types of lighting fixtures in clothes closets is regulated by the proximity of the fixture to what is defined as storage space. Closet storage space is defined in 410.2 as follows:

Storage space includes the area within 24 inches from back and walls of the closet, from the floor up to the highest clothes hanging rod or 6 feet, whichever is higher and above the highest rod or 6 feet, whichever is higher.

The area within 12 inches of the back or walls is considered storage space. If shelves are wider than 12 inches, the area above the shelves (whatever the width of the shelves) must be considered a storage area.

The following types of lighting fixtures ARE permitted in clothes closets [410.16(A)]:

• Surface-mounted or recessed incandescent luminaires that have a completely enclosed lamp
• Surface-mounted or recessed fluorescent luminaires
• Surface-mounted fluorescent or LED luminaires that are identified as suitable for installation in a storage area

The following types ARE NOT permitted in clothes closets [410.16(B)]:

• Incandescent luminaires with open or partially exposed lamps
• Pendant luminaires or lampholders

Note that pull-chain and keyless lampholders may not be installed in clothes closets.

Luminaires in clothes closets must be installed as follows [410.16(C)]:

1.       Surface-mounted incandescent or LED luminaires with a completely enclosed light source can be installed on the wall above the door or on the ceiling if they are at least 12 inches from any storage space.
2.       Surface-mounted fluorescent luminaires can be installed on the wall above the door or on the ceiling if they are at least 6 inches from any storage space.
3.       Recessed incandescent or LED luminaires with a completely enclosed light source can be installed in the wall or the ceiling if they are at least 6 inches from any storage space.
4.       Recessed fluorescent luminaires can be installed in the wall or the ceiling if they are at least 6 inches from any storage space.
5.       Surface-mounted fluorescent or LED luminaires are permitted to be installed within the storage space if they are identified for this use.  

Article 411 - Lighting Systems Operating at 30 Volts or Less

The requirements for these systems are much less stringent than for line-voltage systems, simply because, at 30 volts or less, theses systems are much less likely to cause injury or property damage.

All components of these low-voltage systems must be listed. Additionally, only items described in 411.3(B) are permitted. One clarification for the 2008 NEC is that these systems may be built from components of different manufacturers, provided they are all listed components for these systems.

Another clarification is that the output circuits for these systems (the circuits that deliver power to the lamps) are limited to 25 amperes.

A few other common issues in low-voltage lighting systems are these:

•       Conductors of these systems that pass through a wall, floor, or ceiling must be in a standard wiring method of Chapter 3 or supplied by a Class 2 source and installed according to 725.130.
•       Secondary circuits are not to be grounded [411.5(A)].
•       The primary side of these systems is to be supplied by a branch circuit of no more than 20 amperes.

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