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A momentary high level of amperage flowing in a circuit such as those associated with motorized equipment loads.
120/208-volt, 3Ph, 4W, wye System
A distribution system generated with three individual sine waves separated by 120 electrical degrees that are identified as phases A, B, and C. One leg of each of the three phase coils is electrically connected to the others at a common point, forming a wye, which when grounded, becomes the fourth wire (or neutral) in the system. This allows for each of the three individual phase voltages to supply 120 volts to the ground point, while the lone voltage across each of the phases produces 208 volts. The line-to -line voltages can supply both 208-volt, 3-phase and 208-volt single phase. Because the three individual phases each can supply 120 volts, this system is commonly used in commercial office applications where 120 volts is desired because the 120-volt loads can be balanced across each of the three phases.
277/480-volt, 3Ph, 4W, wye System
A distribution system generated with three individual sine waves separated by 120 electrical degrees that are identified as phases A, B, and C. One leg of each of the three phase coils is electrically connected to the others at a common point, forming a wye, which when grounded, becomes the fourth wire (or neutral) in the system. This allows for each of the three individual phase voltages to supply 277 volts to the ground point, while the lone voltage across each of the phases produces 480 volts. The line-to -line voltages can supply both 480-volt, 3-phase and 480-volt single phase. Because the three individual phases each can supply 120 volts, this system is commonly used in commercial applications where 480 volts is required for machinery loads and in applications to serve 277-volt lighting loads.
A/B Switching Method
A dual switching method to control lighting that reduces the connected lighting load by at least 50 percent, maintains reasonably uniform illumination, and helps meet mandated lighting energy requirements.
American National Standards Institute (ANSI)
An organization that oversees the development of standards created by manufacturers throughout the industry to promote safety and other standards.
An electrical distribution system in which the ungrounded conductors carry equal currents. In distribution systems that also include a grounded conductor, the grounded conductor will carry the imbalance of the currents in the ungrounded conductors.
The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s)
A switch installed to override and automatic lighting shut-off device. (e.g., time clock)
C Value (for conductors)
Multipliers that have been developed for conductors that are derived by including bothe the resistance and the impedance of a conductor (X\R) installed in electrical systems. These multipliers are used in short-circuit calculations and result in calculation of more accurate short-circuit current values.
Color Rendering Index (CRI)
The ability of a lighting source to correctly represent and illuminated object in relation to natural daylight.
A load where the maximum current is expected to continue for three hours or more.
Counter Electromotive Force (CEMF)
An induced voltage that results in a force opposite in direction to the applied voltage; in AC circuits with magnetic properties (such as motors and transformers), this induced voltage can cause the circuit current to lag the applied voltage, resulting in lower power factor values.
The ratio of power consumed by a system at any one time to the maximum power that would be consumed if the entire load connected the system were to be operating at the same time.
Effective Grounding Path
A grounding path of low resistance that ensures, either through raceway methods or additional wiring methods, that the operation of protective devices will occur to isolate a faulted system and thus protect personnel, from the dangers of electrical shock or explosion.
Electrical Apparatus and Service Association (EASA)
An organization that provides information and education about sales, service, and maintenance materials for motors, generators, and other electro-mechanical equipment.
Equipment Grounding Conductor
The conductive path installed to connect normally non-current-carrying metal parts of equipment together and to the system grounded conductor, the the grounding electrode conductor, or to both.
Foot Candel (fc)
A measurement of illumination intensity. One foot candle is the intensity of light on a surface 1 foot from a light source of 1 candlepower.
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