Mike Holt Newsletters

Luminaires - Based on the 2011 NEC

By Mike Holt for EC&M

Article 410 of the NEC covers luminaires, lampholders, lamps, decorative lighting products, lighting accessories for temporary seasonal and holiday use, including portable flexible lighting products, and the wiring and equipment of such products and lighting installations. Even though Article 410 is highly detailed, it’s broken down into 16 parts. The first five are sequential, and apply to all luminaires, lampholders, and lamps, providing mostly mechanical information, and Part VI is Wiring. The rest of Article 410 addresses specific types of lighting except for parts seven, nine, and ten which provide requirements for manufacturers to follow.

The 2008 NEC added allowances for LED luminaires in clothes closets, but inadvertently allowed an LED luminaire to be installed in a clothes closet only if it was identified for that application. The true intent is to allow an LED luminaire to be installed directly within the closet storage space when it’s identified for that application.

Due to the remarkably low amount of heat created by LED luminaires, they’re acceptable anywhere in the closet without special identification for the application—except in the actual storage area. The Code is now clear on the requirements for installing an LED luminaire in a clothes closet. The word “only” was added to the opening statement of 410.16(A), clarifying that only the luminaire types in this section are permitted in a clothes closet (see Sidebar 1).

Another way the NEC recognizes the increasingly widespread use of LED luminaires is seen in the updated requirements for boxes and wiring methods for electric-discharge luminaires to include LED luminaires [410.24].

Grounding/bonding

In previous editions of the NEC, the rules addressing the grounding and bonding of luminaires have been a hodgepodge of requirements in an illogical arrangement. Changes to Part IV of Article 410 make for a more user friendly Code. The changes are editorial, not technical. But they are welcome, all the same.

Don’t forget that Article 250 applies to all electrical installations. The “grounding” requirements for luminaires are actually bonding requirements (see Article 100 definitions). Ensure your lighting system is properly bonded by attaching it to the equipment grounding conductor in accordance with the requirements of 410.44 and Article 250, Part V. Wiring

The rules governing cord-and-plug-connected electric-discharge luminaires have been updated to include LED luminaires in Article 410, part VI.

Because LED drivers and electric-discharge luminaires are quite similar, the logical place to include LED requirements is alongside those of electric-discharge luminaires. Where LED luminaires are supplied by means of a cord-and-plug-connection, they must comply with the provisions of 410.62.

Luminaires as raceways

In previous editions of the NEC, if you wanted to find out whether you could use a luminaire as a raceway, you’d find the answer in 410.64. The answer was a resounding “no.” Section 410.65, however, acted as an exception to this rule.

The problem with this arrangement is that the NEC user probably had stopped looking for allowances to the rule of 410.64, because there were no exceptions to that section. By deleting (2008) 410.65 and incorporating its text into 410.64, the Code becomes an easier document to navigate, understand, and correctly apply.

Installation of lampholders

Previous editions of the Code specified that lampholders in damp or wet locations must be of the weatherproof variety. While this makes sense for wet locations, it doesn’t seem to make sense for a damp location. The 2011 NEC now requires that these lampholders be listed for the environment in which they’re installed [410.96].

Section 410.11 has long required that luminaires installed near combustible material contain shades or guards to prevent the ignition of surrounding products. While that requirement certainly makes sense, there’s a gaping hole in the rule—it doesn’t address lampholders.

Lampholders often contain lamps that produce more heat than a standard luminaire, and seldom has an apparatus been designed to contain that heat. Because lampholders aren’t included in the definition of luminaires, a new section was added: 410.97. The location of this new requirement in Part VIII (Installation of Lampholders) also is logical.

Lampholders must be constructed, installed, or equipped with shades or guards so that combustible material isn’t subjected to temperatures in excess of 90°C (194°F).

Recessed luminaires

The requirements of Article 410 Part X apply to luminaires installed in the recessed cavities of walls and ceilings. Over the years, the applicability of this has been called into question. Many users of the NEC have seen a non-existent loophole that provides an exception for luminaires in suspended ceilings.

Consequently, the technical committee provided a long-standing formal interpretation to clarify that these rules do, in fact, apply to suspended ceilings. This Code change takes that formal interpretation and puts it right in the NEC text, alerting Code users to this fact.

“410.110 General. Luminaires installed in recessed cavities in walls or ceilings, including suspended ceilings, must comply with this part.”

With the 2011 revision of the NEC, the recessed luminaire installation requirements specifically mention LED luminaires [410.116(B)]. Where LED luminaires are of the recessed type, they must be marked as “Type IC,” or have a clearance of 3 in. from thermal insulation.

Discharge lighting

Since its inception in the 2005 NEC, the ballast disconnect in fluorescent luminaires has increased the safety of electricians and maintenance workers. New to the Code with the 2011 revision is a requirement that when you change the ballast on an existing luminaire, you must add a disconnecting means [410.130(G)(1)]. These inexpensive disconnects can provide several benefits (see Sidebar 2).

Design considerations

Article 90’s statement that the NEC is not a design guide is arguably the most true when applied to lighting. A lighting design must account for aesthetics, lumen density, color rendition, energy efficiency, automation and control needs, and many other considerations the NEC does not cover.

Lighting may serve any of several purposes, and often serves two or more at the same time. These include general illumination, task lighting, security, emergency exit, and even complex choreographed lighting for entertainment. Making it even more interesting, indoor lighting, outdoor lighting, and entry way lighting all have differing requirements.

Good lighting design begins with a hard look at the specific areas being lit and the intended use. The architect, industrial engineer, and plant engineer have different ideas on what is most important in a lighting design for a given facility. And the electrical engineer drawing up the plans to power the lighting is probably the only one thinking in terms of lighting transformers and lighting panels.

Whatever the final design is, the luminaires, lampholders, and lamps must be installed in accordance with Article 410.

Sidebar 1. Luminaires in Clothes Closets

Incandescent luminaires with open or partially open lamps and pendant-type luminaires must not be installed in a clothes closet [410.16(B)].

Only the following types of luminaires are permitted to be installed in a clothes closet [410.16(A)]:

Surface or recessed incandescent or LED luminaires with an enclosed light source.
Surface or recessed fluorescent luminaires.
Surface-mounted or recessed LED luminaires identified for use within the closet storage space.

And even then, there are minimum spacing requirements away from storage spaces, depending on the type of luminaire. Luminaires must maintain a minimum clearance from the closet storage space as follows [410.16(C)]:

12 in. for surface-mounted incandescent or LED luminaires with an enclosed light source.
6 in. for surface-mounted fluorescent luminaires.
6 in. for recessed incandescent or LED luminaires with an enclosed light source.
6 in. for recessed fluorescent luminaires.
Surface-mounted fluorescent or LED luminaires are permitted within the closet storage space if identified for this use.

Sidebar 2. Benefits of Ballast Disconnects

Ballast disconnects, now mandated by the NEC, easily justify their cost. The first and foremost consideration is, of course, increased safety. But another benefit is that the use of ballast disconnects can shorten the downtime required to properly change a ballast. In some cases, changing out a ballast may include:

Lockout/tagout to prevent shock hazard to the electrician.
Roping off the work area to prevent any conceivable injury to other workers, such as falling tools.

Changing the ballast while the circuit feeding the luminaire is energized has been a standard practice where there’s no local disconnect. But it’s an unsafe practice to work with energized conductors. Even if the worker does not sustain a fatal shock, a subsequent fall off a ladder can cause death or injury.

With ballast disconnects installed, you don’t need lockout/tagout or the use of PPE, and that shortens your task list, which can result in an increase of overall productivity. But ultimately, any safety innovation that will help make sure that you come home in one piece at night is certainly well worth the bother and expense.

Taken from Mike Holt’s 2011 Understanding the NEC Volume 1 Textbook. To order your copy, please click here, or call 888-632-2633