BU Part 2.2

Admittance

The reciprocal of impedance.

Air Blast Transformer

A transformer cooled by forced circulation of air through its core and coils.

Air Circuit Breaker

A circuit breaker in which the interruption occurs in air.

Air Switch

A switch in which the interruption of the circuit occurs in air.

Alternating Current

A periodic current, the average value of which over a period is zero.

Single Phase Power

Type of Electric Power:Residential Projects

Two Phase Power

Type of Electric Power: Medium Scale Projects

Three Phase Power

Type of Electric Power: Large Scale Commercial and Industrial Projects

Receptacles

Identified by number of poles and wires and whether not the device for connection of separated grounding wire.

2 Pole 3 Wire (Single Outlet)

Alternator (Synchronous Generator)

That changes mechanical power into electrical power

Ammeter

An instrument for measuring electric current.

Ampacity

The current, in amperes, that a conductor can carry continuously under the conditions of use without exceeding its temperature rating.

Ampere

A charge flow of one coulomb per second.

Askarel

A synthetic non-flammable insulating liquid which, when decomposed by electric arc, evolves only non- flammable gaseous mixture

Automatic Transfer Equipment

A device used to transfer load from one power source to another e.g. transfer switch, switchboard assembly, etc.

Autotransformer

A transformer in which part of the winding is common to both the primary and secondary circuits

Auxiliary

A device or equipment which aids the main device

Ballast

A device used with fluorescent and high-intensity discharge lamps to provide the necessary circuit condition for starting and operating the lamp.

Branch Circuit

The circuit conductors between the final overcurrent device protecting the circuit and the outlet(s).

Buna

A synthetic rubber insulation used on wires, cables and other electrical apparatus.

Bus

A conductor or group of conductors that serves as a common connection for three or more circuits in a switchgear assembly.

Cable Sheath

The protective covering such as non-metallic materials as plastic, applied over a cable.

Circuit Breaker

To open the circuit automatically on a predetermined over-current without damage to itself when properly applied within its rating.

Circuit Homerun

In a wiring diagram, an arrow having circuit number designating the point at which such branch circuit will be connected.

Circular Mil

A unit for measuring the cross-sectional area of a conductor (used in MCM conductors)

Conductance

A measure of permissiveness to charge flow; the reciprocal of resistance.

Bare Conductor

A conductor having no covering or electrical insulation whatsoever.

Covered Conductor

A conductor encased within material of composition or thickness that is not recognized by code as electrical insulation.

Insulated Conductor

A conductor encased within material of

composition and thickness that is recognized by

code.

Conduit

A duct or tube for enclosing wires or cables; commonly formed from iron pipe or plastic tubing.

Conduit Fittings

Accessories used to complete a conduit system, such as boxes, bushings and access fitting.

Condulet

A device installed at intermediate points usually at turns to facilitate easy pull through of wires and provide junction of wires

Copper-clad Aluminum Conductor

Conductors drawn from a copper-clad aluminum rod with the copper metallurgically bonded to an aluminum core.

Coulomb

An electric charge of 6.28 x 1018 electrons. One coulomb is transferred when a current of 1 ampere continues past a point for 1 second.

Current

The rate of charge flow. A current of 1 ampere is equal to a flow rate of 1 coulomb per second.

Direct Current

A unidirectional current with a constant value.

Electric Circuit

A conducting path through which electric charges may flow.

DC circuit

A _____ is a closed path for a charge flow

AC circuit

An _____ is not necessarily closed, and may conduct in part by means of an electric field.

Electromagnetic Induction

A process of emf (electromotive force) generation induced by movement of magnetic flux which cuts an electrical conductor; used in generators to produce current.

Electromotive Force (EMF)

An energy-charge relation that results in electric pressure, which produces or tends to produce charge flow

Farad

A unit of capacitance defined by the production of one volt across the capacitor terminals when a charge of one coulomb is stored.

Flashover

A disruptive electrical discharge around or over (but not through) an insulator.

Flexible Conduit

Non-rigid metallic or non-metallic conduit into which conductors may be drawn.

Frequency

The number of periods occurring in unit time of a periodic process such as in the flow of electric charge.

Galvanometer

An instrument for indicating or measuring comparatively small currents.

Fire exit staircase

Where does the standpipe commonly installed?  

Generator

A machine that converts mechanical energy into electrical energy utilizing electromagnetic induction principle.

AC Generator

Also known as Alternator A generator that produces alternating current.

DC generator

A generator that produces direct current

Greenfield

Flexible metal conduit which resembles an armored cable in appearance but is more adaptable than armored cable 

Ground-Fault Circuit Interrupter (GFCI)

A device installed in circuits where current leakage can be especially dangerous, such as outdoor or bathroom circuits

Grounding Conductor

Used to connect equipment or the grounded circuit of a wiring system to a grounding electrode or electrodes

Henry

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.

Individual Branch Circuit

A branch circuit that supplies only one utilization equipment.

Insulated

Separated from other conducting surfaces by dielectric permanently offering high resistance to the passage of current and to disruptive discharge.

Insulator

A material or substance that does not allow the flow of electricity through it.

Inverter

A device that converts direct current (dc) to alternating current (ac).

Jumper

A short length of conductor used to make a connection between terminals, and temporary connection.

Lug

Copper or brass fitting to which electrical wires can be soldered or otherwise connected.

Ohm (symbol: Ω)

The unit of resistance; a resistance of one ohm sustains a current of 1 ampere when 1 volt

Outlet

A point in a wiring system from which current is taken for supply of fixtures, lamps, heaters, etc.

Overcurrent

Any current in excess of the rated current of the equipment or the ampacity of the conductor

Panelboard

A single or group of panel units designed for assembly in the form of a single panel; including buses, automatic overcurrent devices

Pull Box

A metal or a plastic box with a blank cover for insertion into a conduit run, raceway, or metallic

Rectifier

A device that converts alternating current (ac) to direct current (dc).

Resistor

A device designed to introduce resistance into an electric circuit

Series Circuit

A circuit that provides a complete path for current and has its components connected end-to-end.

Service Entrance Conductors (Overhead System)

The service conductors between the terminals of the service equipment and a point usually outside the building

Service-Entrance Conductors (Underground System)

The service conductors between the terminals of the service equipment and the point of connection to the service lateral.

Standby Generator

A generator for providing emergency power during power outage; sometimes called Emergency Generator.

Switch Bank

In switch installation, a place or a point in a building where group of switches used to control group of lamps may be located.

Switchboard

A large single panel, frame or assembly of panels on which are mounted, on the face or back

Switchgear

A general term which covers switching and interrupting devices or apparatus.

Transformer

A static alternating current (ac) device used to change voltage by increasing or reducing it;

Step-up Transformer

A type of transformer used for increasing voltage, e.g. 110 v. to 220 v.

Step-down Transformer

A type of transformer used for decreasing voltage, e.g. 220 v. to 110 v.

Transformer Vault

A fire-rated room containing a transformer and auxiliary equipment for a large building

Tripping

A term denoting interruption or disconnection of contact in devices such as circuit breaker

Volt

The unit of emf (Electromotive Force); 1 volt produces a current of 1 ampere in a resistance of 1 ohm.

Watt

The unit of electrical power, equal to the product of 1 volt and 1 ampere in DC values, or in rms AC values.

André-Marie Ampère (1775 – 1835)

A French physicist who laid the foundations for the science of electrodynamics through his demonstration of the magnetic fields produced by electric currents

Heinrich Hertz (1857 – 1894)

A German physicist who was among the first to demonstrate the existence of electric waves

James Clerk Maxwell (1831 – 1879)

One of the finest mathematicians in history, magnetic fields acting together could produce a new kind of energy called radiant energy

Nikola Tesla (1856 – 1943)

He is best known for developing the alternating current (AC) power system, which revolutionized electricity distribution

Dynamic Electricity (Electrodynamics)

Electricity that flows through a substance or over its surface in the form of an electric current.

 Natural Magnets

Iron ores called magnetite.

Insulation - Class A

What type of Insulation:

(1) Cotton, silk, paper and materials of paper

composition impregnated or immersed in an

insulating

(2) Molded/laminated materials with cellulose

filler, phenolic resin, or similar resins

(3) Films/sheets of cellulose acetate or similar

cellulose products

(4) Varnishes or enamel applied to conductors

Insulation - Class B

What type of Insulation:

Consists of mica, asbestos, or fiberglass; all with a binder.

Insulation - Class C

Consists entirely of mica, porcelain, glass, quartz, or similar materials.

Stranded Wire

Consists of a group of wires twisted to form metallic string

Solid Wire

Consist of a one piece of wire on its entire cross section.

Bus, Busbar

A rigid electric conductor, usually a metal bar, hollow tube, or rod

American Wire Gauge (AWG)

A U.S. standard set of non-ferrous wire conductor sizes

 Open Wiring on Insulators

An exposed wiring method using cleats, knobs, tubes, and flexible tubing for the protection and support of single insulated conductors

Arrmored Cable (Type AC)

A fabricated assembly of insulated conductors in a flexible metal enclosure.

Flat Cable Assemblies (Type FC)

An assembly of parallel conductors formed integrally with an insulating material web

Flat Conductor Cable (Type FCC)

Consists of three or more flat copper conductors placed edge-to-edge and separated

Rigid Nonmetallic Conduit

A type of conduit and fittings of suitable nonmetallic material that is resistant to moisture