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Light the Way

Jan 1, 2012 9:00 AM, By Mike Holt, NEC Consultant

How to install luminaires, lampholders, and lamps in accordance with Art. 410.

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 Art. 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. Part VI focuses on wiring. The rest of this Article addresses specific types of lighting, except for parts 7, 9, and 10, 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 Luminaires in Clothes Closets).

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] (click here to see Fig. 1).

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 Art. 410 make for a more user-friendly Code. Although the changes are editorial — not technical — they are welcome, all the same.

Don’t forget that Art. 250 applies to all electrical installations. The “grounding” requirements for luminaires are actually bonding requirements (see Art. 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 Art. 250, Part V (click here to see Fig. 2).

The rules governing cord- and plug-connected electric-discharge luminaires have been updated to include LED luminaires in Art. 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 (click here to see Fig. 3).

Luminaires as Raceways

In previous editions of the NEC, if you wanted to find out whether or not you could use a luminaire as a raceway, you would 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 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 these lampholders to 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. Although 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, the new section 410.97 was added. 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 Art. 410, Part X apply to luminaires installed in the recessed cavities of walls and ceilings. Over the years, the applicability of this application has been called into question. Many users of the NEC have seen a nonexistent 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.

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