Glossary of Electrical Terms Flashcards
a metal or plastic box with a blank cover for insertion into a conduit run, raceway, or metallic tubing, which facilitates the drawing of conductors
pull box
a channel for holding wires or cables; constructed from metal, wood, plastics, rigid metal, electrical metal tubing, cast-in-place, underfloor, surface metal, surface wooden types, wireways, busways and auxiliary gutters
raceway
constructed, protected or treated so as to prevent rain from interfering with the successful operation of the apparatus under specified test conditions
rainproof
constructed or protected so that exposure to a beating rain will not result in the entrance of water under specified test conditions
raintight
is the voltage to which operating and performance characteristics are referred
rated voltage
is a contact device installed at the outlet for the connection of an attachment pulg
receptacle
an outlet where one or more receptacles are installed
receptacle outlet
a device that converts alternating current to direct current
rectifier
a physical property that opposes current and dissipates real power in the form of heat
resistance
a circuit that provides a complete path for current and has its components connected end-to-end
Series circuit
service conductors made up in the form of a cable
service cable
the conductors from the service point to service disconnecting means
service conductors
the overhead service conductors from the last pole or other aerial support to and including the splices, if any, connecting to the service entrance conductors at the building and other stuctures
service drop
the service conductors between the terminals of the service equipment and a point usually outside the building, clear of building walls , where joined by tap or splice to the service drop
service entrance conductors (Overhead system)
the service conductors between the terminals of the service equipment and the point of connection to the service lateral
service-entrance conductors (underground system)
the necessary equipment, usually consisting of a circuit breakers, or switches and fuses and their accessories connected to the load end of service conductors to a building or other structure or an otherwise designated area and intended to constitute the main control and cutoff of the supply
service equipment
the underground service conductors between the street main, including any risers at a pole or other structure or from the transformers, and the first point of connection to the service entrance conductors in a terminal box or meter other enclosure, inside or outside the building wall
service lateral
the point of connection between facilities of the serving utility and the premises wiring
servie point
the raceways that encloses the service-entrance conductors
service raceways
the value of the current at which the circuit breaker is set to trip
setting
a generator for providing emergency power during power outage; sometimes called emergency generator
standby generator
a protective device for limiting surge voltage on equipment by discharging or bypassing surge current; it prevents continuous flow of follow current to ground and is capable of repeating these functions as specified
surge arrester
the reciprocal of impedance
admittance
a transformer cooled by forced circulation of air through its core and coils
air blast transformer
a circuit breaker in which the interruption occurs in air
air circuit breaker
a switch in which the interruption of the circuit occurs in air
air switch
a periodic current, the average value of which over a period is zero
alternating current
a synchronous alternating-current machine that changes mechanical power into electrical power
alternator (synchronous generator
an instrument for measuring electric current
anmeter
the current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating
ampacity
a charge of flow of one coulomb per seconf
ampere
current-consuming equipment, fixed or portable, such as heating or motor0operated euqipment
appliance
a branch circuit that supplies energy top one or more outlets to which appliances are to be connected, and that has no permanently connected lighting fixtures that are not a art of an appliance
appliance branch circuit
a cable provide with a wrapping of metal, usually steel wires, primarily for the purpose of mechanical protection
armored cable
a synthetic non=flammable insulating liquid which, when decomposed by electric arc, evolves only non-flammable gaseous fixture, usually used in transformers as insulator
askarel
a device used to transfer load from one power source to another e.g. transfer switch, switchboard assembly, etc.
automatic transfer equipment
a transformer in which part of the winding is common to both the primary and secondary circuits; output voltage adjusts automatically depending on required voltage of utilisation equipment
autotransformenr
a device or equipment which aids the main device or equipment
auxiliary
a sheet metal enclosure for conductors, cables, and bus bars at switchboards, meter centers, distribution centers and similar points
auxiliary gutter
a device used with fluorescent and high-intensity discharge lamps to provide the necessary circuit condition for starting and operating the lamp
ballast
the circuit conductors between the final over current device protecting the circuit and the outlets
branch circuit
a conductor that branches off at an angle from a continuous run of conductor
branch conductor
a synthetic rubber insulation used on wires, cables and other electrical apparatus
buna
a conductor or group of conductors that serves as a common connection for three or more circuits in a switchgear assembly
bus
a metallic bar used to provide common contact or termination for a group of all wires or cables such as in an auxiliary gutter, panelboard or a switchboard assembly
busbar
the protective covering such as non-metallic materials as plastic, applied over a cable
cable sheath
a device designed to open and close a circuit by non-automatic means and to open the circuit automatically on a predetermined over-current without damage to itself when properly applied within its rating
circuit breaker
in a wiring diagram, an arrow having circuit number designating the point at which such branch circuit will be connected
circuit homerun
a unit for measuring the cross-sectional area of a conductor (used in MCM conductors); wires and cables are presently measured by its diameter (mm) or cross-sectional area (sq. mm.)
circular mil
a measure of permissiveness to charge flow; the reciprocal of reisstance
conductance
a substance that has free electrons or other charge carriers which permit charge flow when an emf (electromotive force) is applied across the substance
conductor
a conductor having no covering or electrical insulation whatsoever
bare conductor
a conductor encased within material of composition or thickness that is not recognised by code as electrical insulation
covered conductor
a conductor encased within material of composition and thickness that is recognized by code
insulated conductor
a measure of the ability of a material or substance to conduct electric current, equal to the reciprocal of the resistivity of the substance
conductivity
a structure containing one or more ducts; commonly formed from iron pipe or other tubing
conduit
accessories used to complete a conduit system, such as boxes, bushings and access fitting
conduit fittings
an outlet which receives the plug with flexible cord of electrical appliances or equipment such as lamps, refrigerator, television set, power tools, etc.
convenience outlet
conductors drawn from a copper-clad aluminum rod with the copper metallurgical bonded to an aluminum core. the copper forms ten 910) percent of the cross-sectional area of a solid conductor or each strand of a stranded conductor
copper-clad aluminum conductor
an electric charge of 6.28 x 10^18 electrons and is transferred when a current of 1 ampere continues past a point for 1 second
coulomb
the rate of charge flow
current
an enclosure designed for surface mounting that has swinging doors secured directly to and telescoping with walls of the box proper
cutout box
the ratio of the maximum demand of a system, or part of a system, to the total connected load of a system or part of the system under consideration
demand factor
a unit of an electrical system that is intended to carry but not utilize electric energy
device
an unidirectional current with a constant value
direct current
a device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply
disconnecting means
a point at which energy is divided among feeders or branch or combination of both, and where overcurrent devices are usually located
distribution center
a conducting path through which electric charges may flow. a dc circuit is a closed path for a charge flow; an ac circuit is not necessary closed and may conduct in part by means of an electric field
electric circuit
a device for converting electrical energy into mechanical energy
electric motor
the entire system of conductors, equipment and devices that are interconnected to sources of potential difference for distribution and or utilization of electrical energy
electrical system
in practical system, electrical units comprise the volt, ampere, ohm, watt, watt-hour, coulomb, henry, farad, joule, etc.
electrical units
a transient wave of current, potential or power in the electric circuit
electrical surge
a physical entity associated with the atomic structure of matter that occurs in polar forms (positive and negative) and that are separable by expenditure of energy
electricity
a process of emf (electromotive force) generation induced by movement of magnetic flux which cuts an electrical conductor
electromagnetic induction
an energy-charge relation that results in electric pressure, which produces or tends to produce charge flow
electromotive force (EMF)
a branch of electrical science dealing with the laws of electricity at rest
electrostatics
a temporary source of light provided by a lamp powered by storage battery within the unit
emergency light
a unit of capacitance defined by the production of one volt across the capacitor terminals when a charge of one coulomb is sotred
farad
all circuit conductors between the service equipment, the source of a separately derived system, or other power supply source and the final branch-circuit over-current device
feeder
a disruptive electrical discharge around or over (but not through) an insulator
flashover
non-rigid conduit which conductors may be drawn
flexible conduit
the number of periods occurring in unit time of a periodic periodic process such as in the flow of electric charge
frequency
a protective device with a fusible element that opens the circuit by melting when subjected to excessive currentq
fuse
an instrument for indicating or measuring comparatively circuit by melting when subjected to excessive current
galvanometer
a branch circuit that supplies a number of outlets for lighting and appliances
general purpose branch circuit
a machine that converts mechanical energy into electrical energy utilitizing electromagnetic induction principle
generato
also know as alternator. a generator that produces alternating current
ac generator
a conducting connection, whether intentional or accidental, between an electric circuit or equipment and the earth, or to some conducting body that serves in place of the earth
ground
a circuit in which one conductor or point (usually the neutral conductor or neutral point of transformer or generator winding) is intentionally grounded, either solidly or through a grounding service
grounded circuit
a system or circuit conductor that is intentionally grounded
grounded conductor
a device installed in circuits where current leakage can be especially dangerous, such as outdoor or bathroom circuits; shuts off current flow within 0.025 second at the onset of leak as small as 5 milli-amperes
ground-fault circuit interrupter (GFCI)
a conductor used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes
grounding conductor
the conductor used to connect the grounding electrode to the equipment grounding conductor, to the grounded conductor, or to both, of the circuit at the service equipment or at the source of a separately derived system
grounding electrode conductor
a unit of inductance; it permits current increase at the rate of 1 ampere per second when 1 volt is applied across the inductor terminals
henry
the magnetic property of a substance which results from residual magnetism
hysteresis
opposition to AC current by a combination of resistance and reactance; impedance is measured in ohms
impedance
a branch circuit that supplies only one utilization equipment
individual branch circuit
separated from their conducting surfaces by dielectric permanently offering high resistance to the passage of current and to disruptive discharge
insulated
a material or substance that does not allow the flow of electricity through it
insulator
the highest current rating at rated voltage that a device is intended to interrupt under standard test conditions
interrupting rating
a device used to convert direct current to alternating current
inverter
a switch intended for isolating an electrical circuit from the source of power
isolating switch
a short length of conductor used to make a connection between terminals or around a break in a circuit, r around an instrument. it is usually a temporary connection
jumper
a box with a blank cover which serves the purpose of joining different runs of raceway or cable, and provided with sufficient space for connection and branching of the enclosed conductors
junction box
a unit of energy, equal to the energy transferred or expended by one kilowatt in one hour
kilowatt-hour
an instrument or device used to measure power consumption measured in kilowatt-hours
kilowatt-hour meter
a switch in which the circuit is closed by moving a blade engaging contact clips; such type is used in safety switch design
knife switch
an outlet used for direct connection of a lampholder, lighting fixture, or a cord that supplies a lampholder
lighting outlet
device for providing path by which lightning disturbances or other static discharges are passed to earth; this is primarily intended to prevent damage to electrical apparatus due to lightning
lightning arrestor
device for providing path by which lightning disturbances or other static discharges are passed to earth; this is primarily intended to prevent damage to electrical apparatus due to lightning
lightning arrestor
partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold storage warehouse.
damp location
a location not normally subject to dampness or wetness. a location classified as dry may be temporarily subject to dampness of wetness, as in the case of a building under construction
dry location
installations underground or in concrete slabs or masonry in direct contact with earth, and locations subject to saturation with water or other liquids, such as vehicle washing areas, and locations exposed to weather and unprotected
wet location
is the largest of all the demands which have occurred during the specified period of time
maximum demand
a component so constructed that the conducting parts are entirely enclosed in metal casing or enclosure
metal-clad
a point or a place where all meters in a building may be located; usually located in the service area of a building for convenience and easy access
meter center
a device, equipment or conductor so constructed or treated that exposure to a moist atmosphere will not readily cause injury or harmful effect in its quality
moisture-resisant
the unit of conductance defined as the reciprocal of the ohm
mho
the unit of resistance
ohm
an instrument for measuring resistance values
ohmmeter
a law stating that current is directly proportional to the applied voltage and inversely proportional to resistance, reactance or impedance
ohm’s law
a point in a wiring system from which current is taken for supply of fixtures, lamps, heaters, etc
outlet
any current in excess of the rated current of the equipment or the ampacity of the conductor; it may result form overload, short circuit or ground fault
overcurrent
operation of equipment in excess of normal, full load rating or of a conductor in excess of rated ampacity that, when it persists for a sufficient length of time, would cause damage or dangerous overheating
overload
a single or group of panel units designed for assembly in the form of a single panel; including buses, automatic overcurrent devices and equipped with or without switches for the control of light, heat, or power circuits; designed to be places in a cabinet or cutout box placed in or against a wall or partition and accessible only from the front
panelboard
a device inserted into a receptacle for connection of a cord to the conductor terminations in the receptacle
plug
is produced when 1 unit of work is done in separating unit charges through unit distance
potential difference
the rate of doing work, or rate of converting energy when 1 volt is applied to a load and the current demand is 1 ampere, the rate of energy conversion is 1 watt
power
an enclosed assembly that may include receptacles, circuit breakers, fuseholders, fused switches, buses and watt-hour meter mounting means
power outlet
a device for making, breaking, or rearranging the connections of an electrical circuit
swicth
in switch installation, a place or a point in a building where group of switches used to control group of lamps may be located
switch bank
a large single panel frame or assembly of panels on which are mounted, on the face or back or both , switches, over-current and other protective devices, buses, usually instrument
switchboard
a general term which covers switching and interrupting devices or apparatus
switchgear
a device used for transferring one or more load- conductor connections from one power source to another such as an automatic transfer switch or manual transfer switch
transfer switch
a static alternating current device used to change voltage by increasing or reducing it; it consists of windings, with or without taps, with or without magnetic core, used for introducing mutual coupling by induction between circuits
transformer
a type of transformer used for increasing voltage
step-up transformer
a type of transformer used for decreasing voltage
step-down transformer
a fire-rated room containing a transformer and auxiliary equipment for a large building, usually located on grade or below ground and ventilated directly to the outside air
transformer vault
the drop in voltage due to transmission of electricity in wires which is attributed to several factors such as resistance and length of conductor and temparature
transmission loss
a term denoting interruption or disconnection of contact in devices such as circuit breaker, ground fault circuit interrupter and other similar devices
tripping
a cable designed, constructed and specified for use below grade application
underground cable
an emergency system designed to provide power automatically and instantaneously upon failure of the normal power supply
uninterruptible power supply
equipment which utilises electric energy for mechanical, chemical, heating, lighting or similar purposes
utilisation equipment
a metallic or non-metallic box intended for receptacle outlet or switch plate installation
utility box
the unit of emf; it produces a current of 1 ampere in a resistance of 1 ohm
volt
the drop in electric pressure in a circuit due to resistance of the conductor
voltage drop
constructed so that moisture will not enter the enclosure under specified test conditions
watertight
the unit of electrical power, equal to the product of 1 volt and 1 ampere in dc values, or in rms ac values
watt
constructed or protected so that exposure to the weather will not interfere with successful operation
weatherproof
