George W Flach wrote the Code Q&A column For roughly 40 years; regular readers are likely used to a certain format and style could not and did not wish to replicate. He was truly one-of-a-kind. That said, we want to maintain an outlet for all your National Electrical Code (NEC) questions. So we’re continuing the column, with a different spin. This column will replace Code Q&A. We welcome Charlie Trout, a well-known NEC expert. He already has experience answering questions, with his “Code Question of the Day” feature on the National Electrical Contractors Association (NECA) Web site. If you have a Code-related problem, are experiencing difficulty in understanding a NEC requirement, or are wondering why or if such a requirement exists, then ask Charlie, and he’ll let the Code decide.
So let’s get started. This month is all about lighting.
Why does the NEC refer to lighting fixtures as “luminaires?”
For the 2002 edition of the NEC, the Code-making panel accepted a proposal to change all lighting fixture references to luminaires. The basic substantiation was that lighting fixtures were generally referred to simply as fixtures, and fixtures could be plumbing, household or any one of many other fixture designations. The Code-making panel decided that luminaire would more accurately describe the lighting unit. Additionally, luminaire is the international term used for lighting fixtures. For the 2002 Code, in Article 410, luminaire was substituted for the word fixture with the term “fixture(s)” following the word luminaire. For subsequent editions, the term “fixture” was eliminated.
The definition of luminaire in Article 100 calls for a complete lighting unit, including a light source, such as a lamp or lamps. When I purchase a fluorescent luminaire or any other type of luminaire, it does not include the lamp. Isn’t this inconsistent with the definition?
No. There are many types of lamps that can be properly used in luminaries, and it is the installer’s responsibility to put the proper type of lamp together with the luminaire to complete it.
Compact fluorescent lamps (CFLs) are now being used extensively to conform to global energy conservation. What is the advantage in using these lamps, and where in the Code are these types of lamps recognized?
The NEC does not specifically use the term “compact fluorescent lamps” and relies on compliance with the manufacturers’ requirements [110.3(B)] and the listing information shown in “The Guide Information for Electrical Equipment” (White Book), published by Underwriters Laboratories Inc., under Lamps, Self-Ballasted (OOKH). CFLs can be used to replace most medium-base incandescent lamps. A CFL produces more lumens per watt than an incandescent lamp. A lumen is a measurement of visible light output from a lamp. A 23-watt CFL produces the same lumen output as a 100-watt incandescent lamp. CFLs with ratings of 12, 19 and 28 watts that take the place of three-way 50W, 100W and 150W lamps are available. Some CFLs even are dimmable.
What are these new light-emitting diode (LED) luminaires that are permitted to be used in clothes closets?
LED luminaires are a new technology with a very low energy source. LEDs are solid-state devices that depend on a self-contained power supply (driver) for operation. The 2008 NEC recognized LED luminaires; they are specifically referred to in 410.16(A)(3) and 410.16(C)(1), (3) and (5) for use in clothes closets. An LED luminaire must be listed as suitable for use in a clothes closet. According to “Electric Wiring Residential” by Ray Mullin, published by Delmar, there are LED lamps that are direct replacements for a 40-watt fluorescent lamp. You just replace the existing fluorescent lamp with an LED lamp. They will work on both magnetic and electronic ballasts. The LED lamp has a 10-year life, and its power consumption is 20 percent less.
How are track-lighting loads for a residential application calculated?
It is not necessary to add more volt-amperes to the load calculations for track lighting in a residential application. Residential track-lighting loads are a part of the general lighting loads based on the 3 volt-amperes (VA) per square foot shown in Table 220.12. A track-lighting load installation in other than a residential application requires a loading factor of 150 VA for each 2 feet of lighting track. NEC 410.151(B) requires that the connected load on a lighting track must not exceed the rating of the lighting track, and the branch-circuit rating must not exceed the rating of the lighting track.
Is all track lighting rated at 20-amperes?
No. There is heavy-duty lighting track, which is identified for use exceeding 20 amperes. NEC 410.153 requires each fitting attached to a heavy-duty lighting track to have individual overcurrent protection. Keep in mind that a lighting-track fitting is not the same as a fitting defined in Article 100. A lighting-track fitting is a device that is used to fasten a luminaire to the lighting track. It usually performs both an electrical and a mechanical function.
I was asked to replace an existing lighting fixture with a ceiling paddle-fan combination in an existing dwelling-unit bedroom. The unit weighs less than 30 pounds. Can I hang it on the existing box?
NEC 422.18 requires ceiling-suspended paddle fans to be supported independently of an outlet box or by a listed outlet box and installed in accordance with 314.27(D). This NEC section requires the outlet box to be listed for the application. The existing outlet box probably is not listed or identified for this application. Read the manufacturer’s instructions for methods to support the unit independently from the outlet box.
Some manufacturers supply 3-in.-long brass wood screws to be used to secure the fan unit hanger to a ceiling joist if the box is mounted close to it. Check the instructions, and do what is necessary to comply with the requirements. A falling fan unit could be a dangerous result of a thoughtless installation.
Can Type NM cable be used as an exposed wiring method for 277V high-bay fixtures in a warehouse?
No, Type NM cable is permitted to be installed in other than dwelling-type occupancies that are of Types III, IV and V construction. However, in accordance with 334.10(3) in these occupancies, Type NM cable must be concealed within walls, floors or ceilings that provide a thermal barrier that have a 15-minute finish rating. The voltage rating is not the problem. Type NM cable is rated for use at 600 volts.
Does a split-circuit receptacle, which is controlled by a wall switch in a residential bedroom and qualifies as a lighting outlet, also qualify as the receptacle required by 210.52?
Yes, 210.70(A)(1) requires at least one wall-switch-controlled lighting outlet in every habitable room and bathroom in dwelling units. Exception No. 1 permits in those spaces other than bathrooms and kitchens one or more receptacle outlets controlled by a wall switch in lieu of lighting outlets. Remember, a duplex receptacle outlet consists of two receptacles in one outlet, and where 210.52 requires a receptacle outlet, this requirement can be satisfied by a single receptacle.
Is the lighting outlet installed in the attic over a garage required to be a wall switch that is controlled at the bottom of the fold-up ladder?
No, NEC 210.70(A)(3) requires either a switch in the lighting outlet (pull chain) or a wall switch. The switch must be located at the point of entry. The point of entry is at the top of the ladder. If the attic contains equipment that requires servicing, a lighting outlet must be provided at or near the equipment requiring that service.
Are three-way switches required for residential stairways?
If an interior stairway has six risers or more, 210.70(A)(2)(c) requires a wall switch to control the lighting at each floor level and landing level that includes an entryway. This would require three-way and four-way switching, depending on the installation.
Well, that concludes this month’s adventure into NEC lighting requirements. I hope to see you next month same spot, same station, where we will go into questions regarding the NEC requirements for “Motors, Motor Circuits and Controllers.”
TROUT answers the Code Question of the Day on the NECA Web site. He can be reached at 352.527.7035.