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Definition
| – flow of electricity; measure in amperes (amps, A) |
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| potential of the flow of electricity; measured in volts (V) |
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Definition
| – path through which an electric current flows |
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| measure of the amount of power consumed |
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Definition
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Definition
| lamps connected together such that if one goes out the entire string goes out (fig. 11.3, p. 137) |
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Definition
| lamps connected together such that if one goes out current is still provided to the other lamps and they stay on (fig. 11.4, p. 137) |
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Definition
| amount of electrical power consumed over time; measured in kilowatt-hours (kWh) |
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Term
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Definition
Power supplied to a building enters through a service panel this is usually located on the lowest level
Calculating the amount of wattage per square foot due to the lighting system can be found by dividing the total wattage from all lights by the area of the space in which they are located |
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Definition
| Cost of electricity is the largest component for lighting costs because it is an ongoing expense |
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•A cost analysis includes:
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Definition
Initial cost of equipment and lamps
Installation
Electricity costs
Labor for maintaining fixtures |
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Definition
| controls the flow of current between two points |
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Term
| A “single pole, single throw” |
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Definition
| switch is located at any point between the luminaire and the power supply; is either on or off |
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Term
| A “single pole, double throw |
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Definition
| switch directs current in two directions; may turn on two luminaires at the same time or may have a separate position to turn on each of the luminaires with a distinct neutral position that turns both off |
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Term
| A “double-pole, single throw” |
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Definition
| switch directs current to two different paths at the same time (for example, a light and exhaust fan) |
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Term
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Definition
| controls current from two different locations |
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Term
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Definition
| controls current from three different locations |
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Definition
| controls current from four different locations |
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Term
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•Alternate control methods
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Definition
Timers can be used to control the periods of time when a light is on or off
Occupancy sensors switch lights on and off based on the presence of movement in the space; used in combination with a manual switch and are a component in an energy-efficient lighting system
Photosensors monitor the amount of daylight in a space and either turn on/off lighting systems accordingly or adjust electric lighting levels to graduated amounts |
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Term
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Definition
Provide variation in the intensity of electric lights
“Full-range” dimmers provide a continuous variation in lighting levels without visible steps
Dimming increases the lifespan of incandescent lamps but changes the light produced to be more orange
Dimming is available for incandescent low-voltage luminaires |
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Term
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Definition
Dimming is available for some types of fluorescent lamps if the ballast is replaced to one compatible with the dimmer, but light will not go completely off
Dimming is rarely done with high intensity discharge lamps
Dimming reduces the lifespan of fluorescents and HID lamps, but energy savings of dimming compensates for more frequent replacement |
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Term
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Definition
| can be used to control the periods of time when a light is on or off |
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Term
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Definition
| switch lights on and off based on the presence of movement in the space; used in combination with a manual switch and are a component in an energy-efficient lighting system |
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Term
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Definition
| monitor the amount of daylight in a space and either turn on/off lighting systems accordingly or adjust electric lighting levels to graduated amounts |
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