midterms utilities

87問 • 1年前

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a single insulated conductor or a bound or sheathed combination of conductors insulated from one another.

cable

a pliable metallic strand or a twisted or woven assembly of such strands, often insulated with a dielectric material and used as a conductor of electricity

wire

a substance, body, or device that conducts heat, sound, or electricity

conductor

a material that is poor conductor of electricity, used for separating or supporting conductors to prevent the undesired flow of current

insulator

electric cable consisting of two or more insulated conductors protected by a flexible, helically wound metal wrapping. Also called BX cable

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 cable

electric cable consisting of two or more insulated conductors enclosed in a nonmetallic, moisture-resistant, flame-retardant sheath. Also called Romex cable

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 cable

conduit

heavy-walled, tubular steel conduit joined by screwing directly into a threaded hub with lock nuts and bushings

rigid-metal conduit

thin-walled, tubular steel conduit joined by compression or setscrew couplings

electric metallic tubing

a flexible, helically wound metal conduit, used for connections to motors or other vibrating equipment. Also called Greenfield conduits.

flexible metal conduit

an enclosure for 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

a device for making, breaking, or directing an electric current

switch

a conductor having no covering insulation

bare conductor

encased within a material of composition and thickness not recognized by code

covered conductor

encased within a material of composition and thickness not recognized by code

insulated conductor

consists of (1) cotton, silk, paper and materials of paper composition impregnated or immersed in an insulating liquid; (2) molded or laminated materials with cellulose filler, phenolic resin, or resins or similar resins; (3) films or sheets of cellulose acetate or similar cellulose products; and (4) varnishes or enamel applied to conductors

class a

consists of mica, asbestos, or fiberglass, all with a binder

class b

consists entirely of mica, porcelain, glass, quartz, or similar materials

class c

consists of cotton, silk, paper or similar materials that are not impregnated or immersed in an insulating liquid

class o

term given to insulated stranded wire that is flexible

cord

are electrical conductors larger than wires

cable

enclosed channel designed expressly for holding wires, cables, or busbars with additional functions.

raceway

that part of a switch, which is used for making or breaking a connection, and which is electrically insulated from other contact

pole

the direction from a given position in which the contact is made it also indicates the number of times a contact is made

throw

one which will make a close circuit only when a circuit is thrown in one position.

single throw switch

makes a close circuit in either one of the two positions

double throw switch

switches are rated in the following manner

voltage

general use or safety switches intended for general light and power circuits may be of heavy duty (HD), normal duty (ND), or light duty (LD)

duty

a switch may be constructed with or without provision for fusing

fusibility

all switches except snap switches or knife switches mounted on a switchboard must be enclosed in an appropriate cabinet as a protection from external damage

enclosure

these are free standing assemblies of switches, fuses, and/or circuit breakers, which normally provide switching and feeder protection to a number of circuits connected to a main source

switchboard

serves basically the same function as a switchboard, except on a smaller scale that is, it accepts relatively large blocks of power and distributes it in smaller blocks

panelboards

point in the wiring system at which current is taken to supply utilization equipment

outlet

a device that by insertion into a receptacle establishes connection between the conductor of the flexible cord and the conductors connected permanently to the receptacle. The common wall outlet is called

convenience outlet

outlet intended for direct connection to a lamp holder, lighting fixture, or a pendant cord, terminating in a lamp holder

lighting outlet

identified by the number of poles and wires, and whether or not the device is designed for connection of a separate grounding wire

receptacle outlet

due to mechanical overload or internal or external electrical faults

overcurrent

due to short-circuiting between primary and secondary wiring or due to lightning strikes

overvoltage

cutting off or disconnection of the supply current

tripping

overcurrent protective device with a circuit opening fusible element, which is heated and severed by the passage of overcurrent through it

fuse

vented fuse unit in which the expulsion effect of gases produced by the arc and lining of the fuse holder, either alone or aided by a spring, extinguishes the arc

expulsion fuse unit

a vented, non-vented or controlled vented fuse in which the arc is extinguished by being drawn through solid material, granular material, or liquid, either alone or aided by a spring

power fuse unit

fuse with the provision for the escape of arc gases, liquids or solid particles to the atmosphere during circuit interruption

vented power fuse

a fuse with provision for controlling discharge circuit interruption such that no solid material may be exhausted into the surrounding atmosphere

controlled vented power fuse

it is enclosed in porcelain or rubber commonly used in various electrical appliances, with ratings 1, 3, 5, 6, 8, 15, 20, 25 & 30 amps

plug fuse

it is enclosed in insulating tube (e.g. porcelain, rubber or hard paperboard), with ratings: 1, 3, 6, 10, 15, 20, 25, 30, 35, 40, 50, 60, 70, 80, 90, 100, 110, 150, 175, 200, 250, 275, 300, 325, 350, 400, 450, 500, 600 & larger

cartridge fuse

open wire of low melting point commonly used in the safety power switch

fuse wire

these devices operate on the same principle as any other receptacle but with one exception, when supplying power, it monitors the current at the same time

ground fault circuit interrupter

the supplying of utilities, 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

operated on, powered by, or transmitting high voltage

high voltage

an auxiliary power station where electrical current is converted as from DC to AC, or where voltage is stepped up or down

substation

the overhead portion of service conductors extending from the nearest utility pole to a building

service drop

the underground portion of service conductors extending from a main power line or transformer to a building

service lateral

the portion of a service conductor extending from a service drop or service lateral to the service equipment of a building

service entrance conductor

a meter for measuring and recording the quantity of electric power consumed with respect to time

watt-hour meter

a fire-rated room housing 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

a room containing the service equipment for a large building

switchgear room

the equipment necessary for controlling, metering, and protecting the electric power supply to a building, located near the entrance of the service conductors and usually consisting of a main disconnect switch and secondary switches, fuses, and circuit breakers

service equipment

a generator for providing emergency power during a power outage. Also called emergency generator

standby generator

an emergency system designed to provide power automatically and instantaneously upon failure of the normal power supply

uninterruptible power supply

normally tapped onto the utility lines at a mutually agreeable point at or beyond the property line. The service tap may be a connection on a pole with an overhead service drop to the building, an underground service lateral to the building, or a connection to an underground utility line with a service lateral to the building.

electric service

depending on terrain and other factors, the cost of overhead as compared to underground installation is in the range of 10% to 50%

overhead service

consists of a raceway (conduit) extending from the building to the property line where it is tapped to the main

underground service

transformer” between the high voltage incoming utility lines and the secondary service conductors is required whenever the building voltage is different from the utility voltage

service equipment

are device that changes or transforms alternating current of one voltage to alternating current of another voltage

transformers

the electric meter is generally installed outside the building at the property line wall, or electric post for ready access to the meter reader, making it more difficult to tamper or to install jumpers

electric service metering

to disconnect all the electric service in the building except emergency equipment

service switch

an electrical switch is a device intended for on/off control of an electrical circuit and is rated by current and voltage, duty, poles and throw, fusibility and enclosure.

switches

when initiating the wiring design of a building, it is important to be able to estimate the total building load in order to plan such spaces as transformer rooms, chases, an

load estimating

technical term for the House Wiring Installation

branch circuit

employs the principle of converting electrical energy into heat at a temperature that causes the filament to be incandescent (red or white hot)

incandescent lamp

mercury vapor, electric arc is produced between the opposing electrodes generating some visible light

fluorescent lamp

requires a starter which preheats the cathodes so that less voltage is required to strike an arc

pre-heat lamp

when the lamp is first switched on, a sufficient voltage is applied between the electrodes to strike the arc without preheating them

rapid start lamp

are the most recent developments and the one that is most widely used

instant start fluorescent lamp

contains mercury vapor in a clear quartz arc tube, which when electrically excited, produces visible light of characteristically blue-green colo

mercury lamp

modification of the mercury vapor with an arc of improved color

metal halide lamp

are the newest addition to the HID field

high pressure sodium lamp

monochromatic lamps in the yellow region of the spectrum

low pressure sodium lamp

the tungsten-halogen (also called quartz or quartz-iodine) lamps use a halogen gas cycle to prevent rapid depreciation of the lamp filament and darkening of the transparent envelope

tungsten-halogen lamp

bilat ni muski

KRYZL CHARYNE MICU · 54問 · 1年前

bilat ni muski