Building Utilities (Electrical) Flashcards
The science dealing with the physical phenomena arising from the existence and interaction of electric charges.
Electicity
Potential difference or electromotive force expressed in volts; analogous to pressure in water flow.
Voltage
An amount of power, esp. the power required to operate an electrical device or appliance, expressed in watts.
Wattage
The complete path of an electric current, including the source of electric energy.
circuit
The basic SI unit of electric current, equivalent to a flow of one coulomb per second or to the steady current produced by one volt applied across a resistance of one ohm.
Ampere
The intrinsic property of matter giving rise to all electric phenomena, occurring in two forms arbitrarily given positive and negative algebraic signs and measured in coulombs. Opposite charges attract while like charges repel each other.
Electric charge
The SI unit of electric charge, equal to the quantity of electricity transferred across a conductor by a current of one ampere in one second.
Coulomb
The product of potential difference and current in a direct-current circuit. In an alternating current circuit, power is equal to the product of the effective voltage, the effective current, and the cosine of the phase angle between current and voltage.
Power
The SI unit of power, equal to one joule per second or to the power represented by a current of one ampere flowing across a potential difference of one volt.
Watt
The opposition of a conductor to the flow of current, causing some of the electric energy to be transformed into heat and usally measured in ohms.
Resistance
A machine that converts mechanical energy into electrical energy.
Generator
An electric device consisting of two or more windings wound on the same core, which employs the principle of mutual induction to convert variations of alternating current in a primary circuit into variations of voltage and current in a secondary circuit.
Transformer
The supplying of utilities, such as water, gas and electricity, required or demanded by the public.
Service
The decrease in voltage between two points on a power line, usually caused by resistance or leakage along the line.
Line Drop
Device measuring and recording the quantity of electric power consumed with respect to time.
Watt-hour meter
An auxiliary power station where electrical current is converted, as from DC to AC, or where voltage is stepped up or down.
Substation
Any of the conductors extending from the service equipment to various distribution points in a building.
Feeder
The Fractional part of a period or cycle through which time has advanced, measured from a specified reference point and often expressed as an angle.
Phase
A conducting connection between an electric circuit or device and the earth or other point of zero potential.
Ground
An abnormal, usually accidental condition of low resistance between two points in an electric circuit, resulting in a flow of excess current.
Short circuit
A device containing a strip or wire of fusible metal that melts under the heat produced by excess current, thereby interrupting the circuit.
Fuse
A switch that automatically interrupts an electric circuit to prevent excess current fro damaging apparatus in the circuit or fro causing a fire.
Circuit breaker
A board on which are mounted the switches, fuses, and circuit breakers for controlling and protecting a number of similar branch circuits, installed in a cabinet and accessible from the front only.
Panel
Any of several conducting rods installed at the top of a structure and grounded to divert lighting away from the structure.
Lighting rod
A device for protecting electric equipment from damage by lighting or other high-voltage currents, using spark gaps to carry the current to the ground without passing through the device.
Lighting arrester
The power delivered by a generator or transformer, or the power consumed by an appliance or device.
Load
The greatest load delivered to an electrical system or circuit over a specified interval or time.
Maximum demand
The ratio of the maximum demand to the connected load of an electrical system, used in estimating the required capacity of the system to account for the probability that only a portion of the connected load may be applied at any time.
Demand factor
The portion of an electrical system extending from the final over current device protecting a circuit to the outlets served by the circuit.
Branch circuit
The ratio of the average load on an electrical system over a specific period of time to the peak load occurring in that period.
Load factor
A panel for distributing power to other panels or to motors and other heavy power-consuming loads.
Distribution panel
Of or pertaining to a circuit in which alternating current below 50 volts is supplied by a step-down transformer from the normal line voltage, used in residential systems to control doorbells, intercoms, heating and cooling systems, and remote lighting fixtures.
Low-voltage
A single insulated conductor or a bound or sheathed combination of conductors insulated from one another
Cable
Electric cable consisting of two or more insulated condustors protected by a flexible, helically wound metal wrapping.
Armored cable
Electric cable consisting of a tubular copper sheath containing one or more conductors embedded in a highly compressed, insulating refractory mineral.
Mineral-insulated sheathed cable
Electric cable consisting of two or more insulated conductors enclosed in a nonmetallic, moisture-resistant, flame-retardant sheath.
nonmetallic sheathed cable
A cable for transmitting high-frequency telephone, digital, or television signals, consisting of an insulated conducting tube enclosing an insulated conducting core.
Coaxial cable
An electric cable enclosed within a metallic sheath in order to reduce the effects of external electric or magnetic fields.
Shielded cable
A tube, pipe, or duct for enclosing and protecting electric wires or cables.
Conduit
Heavy-walled, tubular steel conduit joined by screwing directly into a threaded hub with locknuts and bushings.
Rigid-metal conduit
Thin-walled, tubular steel conduit joined by compressions or setscrew couplings.
Electrical metallic tubing
A flexible, helically wound metal conduit, used for connections to motors or other vibrating equipment.
Flexible metal conduit
A channel expressly designed to hold and protect electric wires and cables.
raceway
A raceway designed for exposed installation in dry, nonhazardous, noncorrosive locations.
surface raceway
A surface-mounted raceway designed to house the electrical wires for a circuit and a series of receptacles.
multi-outlet assembly
A substance, body, or device that conducts heat, sound, or electricity.
conductor
A material that is a poor conductor of electricity, used for separating or supporting conductors to prevent the undesired flow of current.
insulator
The minimum applied voltage at which a given insulator breaks down and permits current to pass.
breakdown voltage
The maximum voltage that can be applied to a given material without causing it to break down, usually expressed in volts or kilovolts per unit of thickness.
Dielectric strength
A non-conducting substance.
Dielectric
An enclosure for housing and housing and protecting electric wires or cables that are joined together in connecting or branching electric circuits.
Junction box
A panel in a casing or box that can readily be removed, as by punching, hammering or cutting, to provide an opening into the interior.
Knockout
A rubber or plastic washer inserted in a hole in a metal part to prevent grounding of a wire passing through the hole.
Grommet
An insulating and protective lining for one or more conductors passing through a hole.
Bushing
An enclosed raceway for housing conductors or cables.
Duct
A rigid metal housing for a group of buses insulated from each other and the enclosure.
Bus duct
An open metal framework for supporting insulated electrical conductors.
Cable tray
A switch in which the interruption of a circuit occurs in air.
Air Switch
A form of air switch in which a hinged copper blade is placed between two contact clips.
Knife switch
A switch controlled by a conductor floating in a liquid.
Float switch
A rheostat or similar device for regulating the intensity of an electric light without appreciably affecting spatial distribution.
Dimmer
A resistor for regulating a current by means of variable resistances.
Rheostat
A protective plate surrounding an electric outlet or light switch.
Faceplate
A device for making, breaking, or directing an electric current.
Switch
A switch in which a lever or knob, moving through a small arc, causes the contacts to open or close an electric circuit.
Toggle switch
An obsolete wiring system consisting of single, insulated conductors secured to and supported on porcelain knobs and tubes.
Knob-and-tube wiring
A single-pole, double-throw switch used in conjunction with another to control lights from two locations.
3-way switch
A switch used in conjunction with two three-way switches to control lights from three locations.
4-way switch
A point on a wiring system at which current is taken to supply an electric device or apparatus.
Outlet
A junction box designed to facilitate connecting an electric device or receptacle to a wiring system.
Outlet box
An outlet usually mounted on a wall and housing one or more receptacles for portable lamps or appliances.
Convenience outlet
A female fitting connected to a power supply and equipped to receive a plug.
Receptacle
An outlet having an additional contact for a ground connection.
Grounding outlet
Male fitting for making an electrical connection to a circuit by insertion in a receptacle.
Plug
A plug having a blade for ground connection.
Grounding plug
A small, flexible, insulated cable fitted with a plug to connect a portable lamp or appliance to a receptacle.
Cord
A plastic connector containing a threaded metal fitting for screwing onto the intertwined ends of two or more conductors.
Wire nut
Any of various devices for joining two or more conductors without a permanent splice.
Connector
A flexible insulated conducted for electrically connecting an apparatus to another or to a circuit.
Lead
A short, flexible conductor used in connecting a stationary terminal having a limited range of motion.
Pigtail
A conductive element or device for establishing an electric connection to an apparatus.
Terminal
