| HOME | FAQ | Books |
Links |
AMAZON multi-meters discounts AMAZON oscilloscope discounts Energy-Saving Lamps: The Energy Policy Act of 1992 enacted restrictions on lamps. In October 1995, the common 4-ft, 40-watt T12 linear medium bi-pin fluorescent lamp was eliminated. This was replaced by an energy efficient 34-watt T12 lamp, a direct replacement for the discontinued lamp. The Energy Policy Act was amended drastically in 2005, particularly in the electricity section entitled Title XII. Visit this Web site: http://www.gpo.gov/fdsys/pkg/ PLAW-109publ58/pdf/PLAW-109publ58.pdf Some lamps may be designated F40T12/ES, but the lamp draws 34 watts instead of 40 watts. The "ES" stands for "energy saving." ES is a generic designation. Manufacturers may use other designations such as "SS" for SuperSaver, "EW" for Econ-o-Watt, "WM" for Watt-Miser, and others. The older, high wattage incandescent R30, R40, and PAR38 lamps were also discontinued and replaced with lower wattage lamps. See the sections on "Lamp Shapes" and "Lamp Diameters" in this section. T12 lamps are still found in 4-ft shop lights and square luminaires that use U-tube lamps. Most newer square luminaires have U-tube T8 lamps. In new commercial installations, the T8 lamp has taken over from the T12 lamp. Energy-saving fluorescent lamps use up to 80% less energy than incandescent lamps of similar brightness. Fluorescent lamps can last 13 times or more longer than incandescent lamps. It has been estimated that the total electric bill savings across the country will exceed $250 billion over the next 15 years. Table 3 compares the power factor of various types of ballasts. Note the difference in line current for the different types of ballasts. Class P Ballasts In 410.130(E), we find that all fluorescent bal lasts installed indoors (except simple reactance-type ballasts), both for new and replacement installations, must have thermal protection built into the ballast by the manufacturer of the ballast, as shown in Fgr. 13. Ballasts provided with built-in thermal protection are listed by UL as Class P ballasts. Under normal conditions, the Class P ballast has a case temperature not exceeding 194°F (90°C). The thermal protector must open within 2 hours when the case temperature reaches 230°F (110°C). Some Class P ballasts also have a non-resetting fuse integral with the capacitor to protect against capacitor leakage and violent rupture. The Class P ballast's internal thermal protector will disconnect the ballast from the circuit in the event of excessive temperature. Excessive temperatures can be caused by abnormal voltage and improper installation, such as being covered with insulation. The reason for thermal protection is to reduce the hazards of possible fire due to an overheated ballast when the ballast becomes shorted, grounded, covered with insulation, lacking in air circulation, and so on. Ballast failure has been a common cause of electrical fires. See Fgr. 14 for some important requirements for fluorescent and incandescent luminaires. Cold Temperature and Fluorescent Lamps: Conventional fluorescent lamps will operate satisfactorily in ambient temperatures of 60°F (16°C) or more. In cold temperatures, standard fluorescent lamps will start poorly or possibly not even start. Special ballasts and cold-weather fluorescent lamps are needed. Refer to the manufacturer's literature for instructions relating to cold temperature. Lamp Designations for Rapid Start and Preheat Fluorescent Lamps Example: F40T12/WWX/RS "F"-fluorescent "40"-wattage "T"-tubular shape "12"-diameter of lamp in eighths of an inch "WWX"-color (warm white deluxe) === FGR. 14 Some of the most important UL and NEC requirements for fluorescent and incandescent luminaires. Always refer to the UL Standards, the NEC, and the label and/or instructions furnished with the luminaire. (--) LUMINAIRES -- SEE ARTICLE 410, NEC -- WILL BE MARKED WITH INSULATION TEMPERATURE RATING REQUIRED FOR SUPPLY CONDUCTORS IF OVER 60°C. -- READ THE LABEL AND INSTRUCTIONS FURNISHED WITH THE LUMINAIRE. FLUORESCENT: -- IF BRANCH-CIRCUIT CONDUCTORS ARE WITHIN 3 IN. (75 mm) OF BALLAST, USE 90°C. CONDUCTORS. -- DO NOT USE AS RACEWAY UNLESS LISTED AND IDENTIFIED FOR USE AS RACEWAY. -- ALL FLUORESCENT BALLASTS INSTALLED INDOORS MUST BE CLASS P TYPE. INCANDESCENT: SURFACE: -- FOR SURFACE MOUNTING ONLY. SURFACE -- NOT SUITABLE FOR MOUNTING WITHIN 1½ IN. (38 mm) OF THE SURFACE OF LOW-DENSITY CEILING FIBERBOARD UNLESS MARKED ‘SUITABLE FOR SURFACE MOUNTING ON LOW-DENSITY CELLULOSE FIBERBOARD.’ RECESSED -- SUITABLE FOR RECESSED INSTALLATION. -- MAY BE MOUNTED IN SUSPENDED CEILINGS IF PROVIDED WITH APPROPRIATE HARDWARE FOR MOUNTING TO OR IN SUSPENDED CEILINGS. SUSPENDED -- FOR INSTALLATION IN A SUSPENDED GRID ONLY WHERE THE LAY-IN TILES ARE NOT FASTENED IN PLACE, AND WHERE THE TIE WIRES, T BARS, CEILING TILES AND OTHER COMPONENTS DIRECTLY ASSOCIATED WITH THE GRID ARE NOT PART OF THE BUILDING STRUCTURE. -- THE LUMINAIRES ARE INTENDED TO BE MOUNTED IN THE CEILING OPENINGS. SUSPENDED: -- FOR INSTALLATION IN A SUSPENDED GRID ONLY WHERE THE LAY-IN TILES ARE NOT FASTENED IN PLACE, AND WHERE THE TIE WIRES, T BARS, CEILING TILES, AND OTHER COMPONENTS DIRECTLY ASSOCIATED WITH THE GRID ARE NOT PART OF THE BUILDING STRUCTURE. -- THE LUMINAIRES ARE INTENDED TO BE MOUNTED IN CEILING OPENINGS. RECESSED: TYPE IC: -- MARKED TYPE IC -- MAY BE INSTALLED IN INSULATED CEILINGS WHERE INSULATION AND OTHER COMBUSTIBLE MATERIALS MAY BE IN DIRECT CONTACT WITH AND OVER THE TOP OF THE FIXTURE. -- HAS INTEGRAL THERMAL PROTECTION THAT DEACTIVATES THE LAMP IF THE LUMINAIRE IS MIS-LAMPED. -- IS MARKED ‘NOTICE’ THERMALLY PROTECTED LUMINAIRE. BLINKING LIGHT MAY INDICATE IMPROPER LAMP WATTAGE OR IMPROPER LAMP SIZE. -- MAY ALSO BE MARKED WITH OTHER CONDITIONS THAT WILL CAUSE OVERHEATING AND WILL RESULT IN THE LAMPS BLINKING. -- MAY BE USED IN NONINSULATED CEILINGS. -- USUALLY ARE LOW-WATTAGE LUMINAIRES. TYPE NON-IC: -- FOR INSTALLATION IN UNINSULATED CEILINGS. -- IF INSTALLED IN AN INSULATED CEILING, KEEP INSULATION AT LEAST 3 IN. (75 mm) FROM SIDES AND NOT PLACED OVER THE LUMINAIRE SUCH THAT IT WOULD ENTRAP THE HEAT PRODUCED BY THE LUMINAIRE. -- HAS AN INTEGRAL THERMAL PROTECTION THAT WILL DEACTIVATE THE LAMP IF INSULATION COVERS THE LUMINAIRE, RESULTING IN AN OVERHEATING SITUATION. -- UNLESS OTHERWISE MARKED, KEEP LUMINAIRE AT LEAST ½ IN. (13 mm) FROM COMBUSTIBLE MATERIAL (LIKE WOOD JOISTS) EXCEPT AT SUPPORT POINTS. INHERENTLY PROTECTED: -- IF MARKED INHERENTLY PROTECTED, THE LUMINAIRE IS SO DESIGNED THAT THE SURFACE TEMPERATURE WILL NOT EXCEED 194°F (90°C) EVEN IF THE LUMINAIRE IS COVERED WITH INSULATION, IS MIS-LAMPED OR OVER-LAMPED, AN EXAMPLE MIGHT BE “DOUBLE-WALLED” CONSTRUCTION. -- THESE LUMINAIRES ARE NOT THERMALLY PROTECTED. ==== "RS"-rapid start "FC"-shape (circular) "FB" or "FU"-U-shaped, bent Lamp Shapes "A"-standard shape, general use "P" or "PS"-pear shaped (150 watts and larger) "C"-cone shape, like a night light or Christmas tree bulb "F"-flame shape, decorative "G"-globular "PAR"-parabolic shape like a bowl, concentrates light "R"-reflector type; might have reflective material near the base or at the bottom of the lamp; concentrates light. Burn Base Down. Some lamps will be designated as "Burn Base Down." Be sure to follow these words of warning. Lamp Diameters There is a simple way to determine the diameter of a lamp at its widest measurement. The industry uses an "eighths of an inch" rule. For example, the diameter of a T5 fluorescent lamp is 0.625 in. The diameter of a T8 fluorescent lamp is 5 1 in. The diameter of a T12 lamp is 1½ in. Incandescent lamps follow the same system. The diameter of an A21 lamp is 21 / 8 = 2.625 in. The diameter of an R30 lamp is 30 / 8 = 3¾ in. Watts versus Volt-Amperes It is very easy to overload a branch circuit that supplies fluorescent lighting. The most common mistake of making load calculations for fluorescent lighting loads is to use lamp wattage instead of the volt-amperes and total current draw as marked on the ballast's label. The culprits are old-style, low-power factor, low-efficiency ballasts! Let's make a comparison of possibilities for the recreation room lighting where there are six recessed fluorescent luminaires, each containing two 2-lamp ballasts. The nameplate on each ballast indicates a line current rating of 0.70 ampere at 120 volts, which is 84 volt-amperes. The lamps are marked 40-watts. The total current in amperes is 12 x 0.70 = 8.4 amperes The total power in volt-amperes is 8.4 x 120 = 1008 volt-amperes The total lamp wattage is 40 x 24 = 960 watts If we had calculated the load for these luminaires based upon wattage, the result would have been: W/E = 960 / 120 = 8 amperes This result is not much different from the 8.4 amperes using data from the ballast nameplate. Had we used low-cost, low-efficiency ballasts like No. 4 shown in Table 3, the result would be entirely different. The ballasts in Table 3 are single-lamp ballasts. We double the current values for a good approximation of a similar 2-lamp ballast. Using the low-power factor ballast, we find that the total current in amperes is 20.4 amperes The total power in volt-amperes is 2,448 The total lamp wattage is 24 3 40 5 960 watts As previously shown, if we use lamp wattage to calculate the current draw: But we really have a current draw of 20.4 amperes, which would overload the 15-ampere branch circuit B12. In fact, a load of 20.4 amperes is too much for a 20-ampere branch circuit. Two 15-ampere branch circuits would have been needed to hook up the recreation room recessed fluorescent luminaires. Remember, do not load any circuit to more than 80% of the branch circuit's rating. That is 16 amperes for a 20-ampere branch circuit and 12 amperes for a 15-ampere branch circuit. And that is the maximum. It is apparent that the installed cost using cheap luminaires is greater and more complicated than if high-quality luminaires using energy-efficient ballasts and lamps had been used. However, after the initial installation, the energy savings add up significantly. Low-power factor ballasts mean higher light bills! High-efficiency, high-power factor ballasts should always be used. More on the wiring of the lighting in the recreation room is covered in Section 17. === FGR. 15 It is not permitted to install lighting in or on residences where the open-circuit voltage is over 1000 volts. This is a violation of 410.140(B). TRANSFORMER Neon tubing 120-volt supply Open circuit secondary voltage: 15,000 volts === Other Considerations • Because heat trapped by insulation around and on top of a luminaire can shorten the life of a ballast, always follow the manufacturer's installation requirements and the requirements found in Article 410. There is a "nonscientific" rule of thumb referred to as the "half-life rule." It means that for every 21°F (10°C) above electrical equipments (motors, conductors, transformers, etc.) recommended maximum operating temperature, the expected life of that equipment is cut roughly in half. Raising the temperature another 21°F (10°C) will again cut the expected life in half. A 21°F (10°C) temperature rise (Note: This is a tempera ture difference, not an absolute temperature measurement), above the ballast's rated temperature of 90°C can reduce the ballast's life by one-half. This "half-life rule" is also true for conductors, motors, transformers, and other electrical equipment. • Fluorescent lamps that are intensely blackened on both ends should be replaced. Operating a two-lamp ballast with only one lamp working will cause the ballast to run hot and will shorten the life of the ballast. Severe blackening of one end of the lamp can also ruin the ballast. A flickering lamp should be replaced. • Poor starting of a fluorescent lamp can be caused by poor contact in the lampholder, poor grounding, excessive moisture on the outside of the tube, or cold temperature (approximately 50°F [10°C]), as well as dirt, dust, and grime on the lamp. • Most ballasts will operate satisfactorily within a range of 15% to 27% of their rated voltage. The higher quality CBM-certified ballasts will operate satisfactorily within a range of 610%. • Most T12 fluorescent lamps sold today are of the energy-efficient type. Generally, energy efficient fluorescent lamps should not be used with old-style magnetic ballasts. To do so could result in poor starting, reduced lamp life, flickering, or spiraling. Home centers carry the most common T12 fluorescent lamps. Electrical supply houses usually carry different types of fluorescent lamps that can be matched with different types of ballasts. Check the markings on the ballast and the lamp carton, as well as the instructional literature available at the point-of sale of the ballast or lamp, and/or in the manufacturer's catalogs. • Lamp life generally is rated in "X" number of hours of operation based on 3 hours per start. Frequent switching results in shortened expected lamp life. Inversely, leaving the lamps on for long periods of time extends the expected lamp life. Vibration, rough handling, cleaning, and so on, shortens lamp life. • Be careful of the type of conductors you use to connect fluorescent luminaires. Branch circuit conductors within 3 in. (75 mm) of a ballast must have an insulation temperature rating of not less than 90°C, 410.68. Type THHN conductors, the conductors in non metallic-sheathed cable and in Type ACTHH armored cable are rated 90°C. Voltage Limitations The maximum voltage allowed for residential lighting is 120 volts between conductors, per 210.6(A). In or on a home, lighting equipment that operates with an open-circuit voltage over 1000 volts is not permitted, 410.140(B). This pretty much eliminates most neon lighting systems for decorative lighting purposes, as shown in Fgr. 15. Incandescent Lamp Life at Different Voltages Operating an incandescent lamp at other than rated voltage will result in longer-or shorter-lamp life. The following formula predicts the approximate expected lamp life at different voltages. For example, assume that a 120-volt incandescent lamp has a published lamp life of 1000 hours. The calculations show the expected lamp life of this lamp when operated at 130 volts, and the expected lamp life when operated at 110 volts. Incandescent Lamp Lumen Output at Different Voltages Operating an incandescent lamp at a voltage lower than the lamp's voltage rating will result in longer lamp life. A strong case might be made to install 130-volt lamps, particularly where they are hard to reach, such as flood lights located high up. However, the lumen output is reduced. For example, calculate the approximate lumen output of a 100-watt, 130-volt incandescent lamp that has an initial lumen output of 1750 lumens at rated voltage. The lamp is to be operated at 120 volts. Formulae such as these are found in lamp manufacturer's catalogs. These formulae are useful in determining the effect of applied voltage on lamp wattage, line current, lumen output, lumens per watt, and lamp life. A calculator that has a y x power function key is needed to solve these equations. Exponents. Confused? If your calculator does not have a y x function key, take the easy route. Just multiply the number again and again for the value of the exponents (power). Cumbersome… but it works... For example, the number 23 can be read "2 to the third power" or "2 raised to the third power." 2 x 2 x 2 = 8 Another example, the number 85 can be read "eight to the fifth power" or "eight raised to the fifth power." We simply multiply that number 8 by itself five times. = 32,768 Some simple exponents can be read in a certain way for example a2 is usually read as "a squared" and a3 as "a cubed." Fgr. 16 is a graph showing the affect of different voltages on lamp life and lumen output. ==== FGR. 16 Typical operating characteristics of an incandescent lamp. (--) LIFE LUMEN 5040 60 70 80 90 Percent voltage Percent lumen or life Based on the equations: Capital letters indicate rated values for lamp. Lowercase letters indicate actual use values. LIFE VOLTS LUMEN volts VOLTS ==== Keep It Simple! The formulae for lamp life and lumen output are complicated, but here is a quick summary: • An incandescent lamp operating at a voltage less than its rated voltage will last longer but will not burn as bright as it should. • An incandescent lamp operating at a voltage greater than its rated voltage will not last as long but will burn brighter. LAMP EFFICACY: A lumen is a measurement of visible light output from a lamp. One lumen on 1 ft^2 of surface produces 1 foot-candle. Another term you will hear in lighting is efficacy. Efficacy is the ratio of light output from a lamp to the electric power it consumes and is measured in lumens per watt (lm/w). In other words, efficacy is a measurement of input to output. Examples: • Lamp #1: 26-watt compact fluorescent lamp (CFL) produces 1700 lumens at rated voltage, which equates to 65 lm/w. • Lamp #2: 100-watt incandescent lamp produces 1200 lumens at rated voltage, which equates to 12 lm/w. • Lamp #3: 100-watt lamp incandescent produces 1750 lumens at rated voltage, which equates to 17.5 lm/w. The more lumens per watt, the greater the efficacy of the lamp. See Table 2. It is obvious that typical incandescent lamps are very inefficient compared to compact fluorescent lamps. There is a dramatic trend toward the use of CFL lamps: more light for less energy, and less energy means lower electric bills! LAMP COLOR TEMPERATURE Lamp color temperature is rated in Kelvin degrees, and the term is used to describe the "whiteness" of the lamp light. In incandescent lamps, color temperature is related to the physical temperature of the filament. In fluorescent lamps where no hot filament is involved, color temperature is related to the light as though the fluorescent discharge is operating at a given color temperature. The lower the Kelvin degrees, the "warmer" the color tone. Conversely, the higher the Kelvin degrees, the "cooler" the color tone. Incandescent lamps provide pleasant color tones, bringing out the warm red flesh tones similar to those of natural light. This is particularly true for the "soft" and "natural" white lamps. Tungsten filament halogen lamps have a gas filling and an inner coating that reflects heat. This keeps the filament hot with less electricity. Their light output is "whiter." They are more expensive than the standard incandescent lamp. Fluorescent lamps are available in a wide range of "coolness" to "warmth." Warm fluorescent lamps bring out the red tones. Cool fluorescent lamps tend to give a person's skin a pale appearance. Fluorescent lamps might be marked daylight D (very cool), cool white CW (cool), white W (moderate), warm white WW (warm). These categories break down further into a deluxe X series (i.e., deluxe warm white-deluxe cool white), specification SP series, and specification deluxe SPX series. Typical color temperature ratings for lamps are 2800K (incandescent), 3000K (halogen), 4100K (cool white fluorescent), and 5000K (fluorescent that simulates daylight). Note that a halogen lamp is "whiter" than a typical incandescent lamp. Catalogs from lamp manufacturers provide detailed information about lamp characteristics. Fluorescent lamps and ballasts are a moving target. In recent years, there have been dramatic improvements in both lamps and electronic ballast efficiency. First, the now-antiquated T12 fluorescent lamps (40 watts) were replaced by energy-saving T8 fluorescent lamps. These original T8 lamps are becoming a thing of the past. The latest T8 high-efficiency, energy saving (25 watts vs. 32 watts) lamps have an expected 50% longer life than the original T8 lamps. The newer T8 lamps use approximately 40% less energy than the older T12 lamps. At $0.06 per kWh, one manufacturer claims a savings of $27.00 per lamp over the life (30,000 hours) of the lamp. At $0.10 cents per kWh, the savings is said to be $45.00 per lamp over the life of the lamp. Using the newer T8 lamps on new installations and as replacements for existing installations makes the payback time pretty attractive. One electronic ballast can operate up to four lamps, whereas the older style magnetic ballast could operate only two lamps. For a three- or four-lamp luminaire, one ballast instead of two results in quite a saving. Some electronic ballasts can operate six lamps. Hard to believe! You now can have reduced power consumption and increased light output using electronic ballasts. Today's high-efficiency ballasts are available with efficiencies of from 98% to 99%. The only way you can stay on top of these rapid improvements is to check out the Web sites of the various lamp and ballast manufacturers. Today's magnetic and electronic ballasts handle most of the fluorescent lamp types sold, including standard and energy-saving preheat, rapid start, slimline, high output, and very high output. Again, check the label on the ballast. FGR. 17 Some types of LEDs that luminaire manufacturers can use in their product. (A) is a typical single light-emitting diode (LED). (B) is a high light output LED. FGR. 18 LED-powered luminaires. (Hubbell Lighting Outdoor & Industrial ) LED Lighting Light-emitting diode (LED) is pronounced "ell-eee-dee." Reduce the electric bill! Save energy! Reduce energy consumption! Reduce the air-conditioning load! It has been said that the incandescent bulb is from the dinosaur age, having been around since Thomas Edison applied for a patent on May 4, 1880. Coming on strong is a new concept for lighting that uses light-emitting diodes (LEDs) as its source of light. It is called "solid-state lighting." LED lighting has very low power consumption. Electricians had better get ready for this new type of light source in luminaires. Although not quite yet here for general lighting of a room, that will come as the light output of LEDs increases. LEDs are solid-state devices that have been around since 1962. When connected to a dc source, the electrons in the LED smash together, creating light. Think of an LED as a tiny light bulb, but with no filament. Fgr. 17(A) is a typical LED that luminaire manufacturers can cluster in their luminaires to obtain the amount of light output they are looking for. Fgr. 17(B) is a high light output LED that lighting manufacturers can use in their luminaires. Fgr. 18 shows two LED-powered luminaires. Today, LEDs are all around us. They are commonly recognized by the tiny white, red, yellow, green, purple, orange, and blue lights found in the digital displays in TVs, radios, DVD and CD players, remotes, computers, printers, fax machines, telephones, answering machines, Christmas light strings, night lights, "locator" switches, traffic lights, digital clocks, meters, testers, tail lights on automobiles, strobe lights, occupation sensors, and other electronic devices, equipment, and appliances. LEDs for lighting are a rather recent concept. Because the lumens per watt in LEDs are on the increase, it is now making sense to use LEDs in luminaires. Individual LEDs are rather small. Putting a cluster (called an array) of LEDs together (i.e., 5, 20, 30, 60, 120) produces a lot of light. The result is an LED bulb, usable in a luminaire the same as a typical medium Edison-base lampholder incandescent bulb. Fgr. 18 shows three different styles of LED lamps. LED Luminaires and the NEC The 2008 NEC recognized LED lighting for the first time in Article 410, specifically 410.16(A) (3), 410.16(C)(1), and 410.16(C)(3). Other NEC references include 410.24, 410.68, 410.74, 410.116, 410.136, and 410.137. LED lighting is beginning to appear in exit, recessed, surface, and under-cab net luminaires; desk lamps; wall luminaires; down lights; stop-and-go lights; to name a few. LEDs in flashlights have been around for quite a while. Lamp manufacturers have come out with many different types of lamps for accent, task, conventional shape, flood, spots, and so on. They are available with the standard Edison base and candelabra base to replace existing incandescent lamps. The light is white, but with different LEDs other colors are avail able. See Fgr. 19 for an assortment of LED lamps. FGR. 19 An assortment of light bulbs (lamps) powered by a number of individual light emitting diodes (LEDs). These lamps screw into a standard medium Edison-base lampholder. Today's LEDs last 60,000 to 100,000 hours. They produce virtually no heat, have no filament to burn out, can withstand vibration and rough usage, contain no mercury, operate better when cool, lose life and lumen output at extremely high temperatures, and can operate at temperatures as low as 240°F (240°C). The lumen output of LEDs slowly declines over time. The decline varies. The industry seems to be settling on a lumen output rating of 70% after 50,000 hours of use. LEDs use a tiny amount of electricity. Virtually all of the power consumption converts to light, whereas for an incandescent bulb, 5% of the power consumption converts to light and the rest converts to heat. The purpose of lighting is to have illumination-not heat. Heat is a waste. Some LEDs may be dimmed, whereas others may not. Check with the manufacturer of the lamp (bulb) to verify the dimming or no dimming capability. LEDs start instantly with no flickering. LEDs put out directional light as compared to the conventional incandescent lamp that shoots light out in almost all directions. A study was recently made to compare an LED's predicted life of 60,000 hours (that's almost 7 years of continuous burning, or 21 years at 8 hours per day of usage) to a standard 60-watt incandescent lamp that has a rated life of 1000 hours. Over the 60,000 hour life: • 60 standard incandescent lamps would be used compared to one LED bulb. • the standard incandescent lamps would use 3600 kilowatt-hours, resulting in the cost of electricity at $360. The LED lamp would use 120 kilowatt-hours, resulting in a cost of electricity at $12. • the total cost (lamps and cost of electricity) for the incandescent lamps was $400 compared to the cost of operating the LED lamp, which was $47. Today, the lumen output of LED lamps is similar to CFLs, producing approximately 50 lm/w. This is expected to improve to 150 lm/w by 2010. Compare the LED lumen output to a typical incandescent lamp that has a lumen output of 14-18 lm/w. That's a significant increase in lumens per watt! Things Are Changing Fast Recently announced is a line of LED lamps that are direct replacements for the conventional 40-watt fluorescent lamp. Nothing has to be done other than replace the existing fluorescent lamp with an LED lamp. They work on both magnetic and electronic ballasts. When compared to a conventional 40-watt fluorescent lamp, the LED replacement lamp typically has a 10-year life as opposed to a 2- or 3-year life-their power consumption is 20% less and their lumen output is comparable or slightly greater-and they can operate at 32°F (0°C). These LED lamps are currently available in warm white, cool white, daylight, neutral, and bright white. LED lighting is accelerating at a rapid pace. The NEC Code-Making Panels will be seeing more and more proposals for changes in the NEC relating to LED-type luminaires. Keep an eye out for these changes. As with all electrical equipment, carefully read the label on the luminaire to be sure your installation "meets Code." For more information about LEDs and LED lighting, check out the Web site of the LED industry: http://www.ledsmagazine.com. Outdoor Lighting Before installing outdoor lighting, check with the local electrical inspector and/or building official to find out whether there are any restrictions regarding outdoor lighting. A virtually unlimited array of outdoor luminaires is available that provide uplighting, down lighting, diffused lighting, moonlighting, shadow and texture lighting, accent lighting, silhouette lighting, and bounce lighting. After the luminaires are selected, the type and color of the lamp is then selected. Some luminaires have specific light "cut off” data that are useful in determining whether the emitting light will spill over onto the neighbor's property. The method of control must also be considered. Switch control, timer control, dusk-to dawn control, and motion sensors are ways of turning outdoor lighting on and off. In recent years, more and more complaints are coming from neighbors claiming that they are being bothered by glare, brightness, and light spillover from their neighbor's outdoor luminaires. Security lighting, yard flood lights, driveway lighting, "moon lighting" in trees, and shrub lighting are examples of sources of light that might cross over the property line and be a "nuisance" to the next door neighbor. Outdoor "lightscape" lighting considered by a homeowner to be aesthetically wonderful might be offensive to the neighbor. Nuisance lighting is also referred to as light pollution, trespassing, intrusion, glare, spillover, and brightness. Some quiet residential neighborhoods are beginning to look like commercial areas, used car lots, and airport runways because no restrictions govern outdoor lighting methods. This is not a safety issue and is not addressed in the NEC. However, the issue might be found in local building codes. Many communities are being forced to legislate strict outdoor lighting laws, specifying various restrictions on the location, type, size, wattage, and/ or footcandles for outdoor luminaires. Checking building codes in your area might reveal requirements such as these: Light Source: The source of light (the lamp) must not be seen directly. Glare: Glare, whether direct or reflected, such as from floodlights, and as differentiated from general illuminations, shall not be visible at any property line. Exterior Lighting: Any lights used for exterior illuminations shall direct light away from adjoining properties. The International Dark-Sky Association has a lot of information regarding light pollution issues on its Web site: http://www.darksky.org. Replacing a Luminaire in an Older Home: Will There Be Problems? Very possible! Older homes were wired with conductors that were insulated with rubber (Type R) or thermoplastic (Type T). Both of these older style insulations were rated for maximum 60°C. The heat generated by the lamps over the years literally baked the conductor insulation to a hard, brittle material particularly is the luminaires were over-lamped. If you aren't careful, pulling on or moving these conductors can easily break off the conductor insulation, which will result in a hazardous short-circuit or ground-fault situation. Handle with care! Being very careful in handling the conductors while making up the splices and mounting the new luminaire-possibly sliding some readily available tubing-like electrical insulation-or taping over the conductor insulation with plastic electrical tape might be all that is needed. Many modern luminaires are marked by the manufacturer with a requirement for wiring the luminaire with either 75°C or 90°C supply conductors. You may need to do some rewiring using the latest in nonmetallic-sheathed cables Type NM-B, Type NMC-B, or Type NMS-B. If the conductors are in a raceway, replacing the conductors with Type THHN might be a good idea. All of these conductors have a maximum temperature rating of 90°C. Another common correction method is shown in Fgr. 20. Install a junction box approximately 24 inches from the location of the new luminaire. Connect a wiring method having conductors with an insulation system rated for the marked supply temperature from the junction box to the luminaire. It is best if the junction box is located in the attic or other accessible location. Otherwise, install a blank canopy over the junction box if it is exposed on the ceiling. More on this subject is found in Section 4 in the nonmetallic-sheathed cable section. === Type NM Cable Conductors suitable for supply temperature required for fixture Original branch circuit conductors rated at 60°C Luminaire marked as requiring supply wiring rated at 75°C or 90°C FGR. 20 Installing luminaire requiring higher temperature supply conductors on a lower-rated older wiring system. == =
QUIZ
1. Is it permissible to install a recessed luminaire directly against wood ceiling joists when the label on the luminaire does not indicate that the luminaire is suitable for insulation to be in direct contact with the luminaire? This is a Type Non-IC fixture. 2. If a recessed luminaire without an integral junction box is installed, what extra wiring must be provided? 3. Thermal insulation shall not be installed within in. (mm) of the top or in. (mm) of the side of a recessed luminaire unless the luminaire is identified for use in direct contact with thermal insulation. This is a Type Non-IC fixture. 4. Recessed luminaires are available for installation in direct contact with thermal insulation. These luminaires bear the UL mark "Type ." 5. Unless specifically designed, all recessed incandescent luminaires must be provided with factory-installed. 6. Plans require the installation of surface-mounted fluorescent luminaires on the ceiling of a recreation room that is finished with low-density ceiling fiberboard. What sort of mark would you look for on the label of the luminaire? 7. A recessed luminaire bears no marking indicating that it is "Identified for Through Wiring." Is it permitted to run branch-circuit conductors other than the conductors that supply the luminaire through the integral junction box on the luminaire? 8. Fluorescent ballasts for all indoor applications must be type. These ballasts contain internal protection to protect against overheating. 9. Additional backup protection for ballasts can be provided by connecting a(an) __ with the proper size fuse as recommended by the ballast manufacturer. 10. You are called upon to install a number of luminaires in a suspended ceiling. The ceiling will be dropped approximately 8 in. (200 mm) from the ceiling joists. Briefly explain how you might go about wiring these luminaires. 11. The Code places a maximum open-circuit voltage on lighting equipment in or on homes. This maximum voltage is (600) (750) (1000). (Circle the correct answer.) Where in the NEC is this voltage maximum referenced? 12. The letter "E" in a circle on a ballast nameplate indicates that the ballast ___. 13. A 120-volt lamp fluorescent ballast for two 40-watt lamps is marked 85 volt-amperes. What is the power factor of the ballast? 14. Can an incandescent lamp dimmer be used to control a fluorescent lamp load? 15. A good "rule-of-thumb" to estimate the expected life of a motor, a ballast, or other electrical equipment is that for every °C above rated temperature, the expected life will be cut in ___ . 16. A post light has a 120-volt, 60-watt lamp installed. The lamp has an expected lamp life of 1000 hours. The homeowner installed a dimmer ahead of the post light and leaves the dimmer set so the output voltage is 100 volts. The lamp burns slightly dimmer when operated at 100 volts, but this is not a problem. What is the expected lamp life when operated at 100 volts? 17. Does your community have exterior outdoor lighting restrictions? If yes, what are they? 18. Define the following terms. a. A tap conductor is b. A fixture whip is ____ 19. Circle the correct answer for the following statements: a. Always match a fluorescent lamp's wattage and type designation to the type of ballast in the luminaire. (True) (False) b. It really makes no difference what type of fluorescent lamp is used, just so the wattage is the same as marked on the ballast. (True) (False) 20. Circle the correct answer for the following statements. a. When selecting a trim for a recessed incandescent luminaire, select any trim that physically fits and can be attached to the luminaire. (True) (False) b. When selecting a trim for a recessed incandescent luminaire, select a trim that the manufacturer indicates may be used with that luminaire. (True) (False) 21. Have you installed LED lighting? Add comments on your experience involving LED lighting. Prev. | Next |