COSC 325 - Electrical Exam

Electrical energy calculations (kWh)

E=PxT

Electrical Metallic tubing (EMT)

a light-gauge electrical pipe often referred to as thin-wall conduit

Quick connector

a mechanical connection method used to secure wires to the backs of switches and receptacles

Type NM cable (aka "Romex")

a nonmetallic-sheathed cable that has the conductors enclosed within a nonmetallic jacket and is typically used for dry interior wiring

Color coding

is a technique used to identify switch terminal screws through use of various colors (bronze, silver, or green)

Tape

many types but plastic insulates against voltages up to 600 V per wrap, typically used in residential wiring

Conductor

material that has very little resistance and permits electrons to move through it easily

Conductor materials

material that has very little resistance and permits electrons to move through it easily

2 methods for grounding an electrical system

metal water pipe and alternative electrode

Pigtail

most common, twisting two ends of wire together (taped-ends bent, nuts-ends cut off)

Three way

used in pairs to control a light or load from 2 locations

DC voltage

voltage that flows in 1 direction only (portable equipment)

AC voltage

voltage that reverses its direction of flow at regular intervals (res,com,indust lighting and power distribution systems)

Portable cord

weak splice because there is no connector to hold the conductors together

LOTO

Lockout/Tagout

Electrical circuit

an assembly of conductors (wires), electrical devices (switches and receptacles), and components (lights and motors) through which current flows

Electron current flow

flow from - to +

Generated electricity

the alternating current (AC) created by power plant generator

Three phase

three distinct wave cycles, 3-wires, 415V

Three

(AC) a combination of three alternating voltage waveforms, each displace 120 electrical degrees apart

Single

(AC) contains only one alternating voltage waveform

Incandescent

(most widely used) is an electric lamp that produces light by the flow of current through a tungsten filament inside a sealed glass bulb sometimes filled with a gas

Soldering

Commonly used with 60% tin & 40% lead, Tin = strength of the solder, Lead = melting point of the solder to the metal surface, Flux added to solder to clean metal surfaces and ensure adheres, Common kinds are rocin core (preferred on small electrical applications) and acid core (never be used on electrical connections)

Converting celsius to fahrenheit

F=(1.8xC)+32

NEMA 1

For indoor use. Protects users against contact with hazardous components and protects the components from the ingress of solid objects, such as fingers and falling dirt.

NEMA 3R

Same as NEMA 3 but without the protection against windblown dust. The standard doesn't say this, but typically the difference is that there is no gasketing on NEMA 3R enclosures.

Resistive circuit

a circuit that contains only resistive components, such as heating elements and incandescent lamps

Circuit

a complete path (when on) for current to take and includes electrical control devices, circuit protection, conductors, and load(s)

Receptacle (not all the different types, just basic function)

a contact device installed for the connection of plugs and flexible cords to supply current to portable electrical equipment

Rectifier

a device that converts AC to DC by allowing the voltage and current to move in only one direction

Wiring plan

a drawing that indicates the placement of all electrical devices and components and the wiring required to connect all the equipment into circuits

GFCI Receptacle

a fast acting receptacle that detects low levels of leakage current to ground and opens the circuit in response to the leakage

Ground Fault Circuit Interrupter (GFCI)

a fast-acting receptacle that detects low levels of leakage current to ground and opens the circuit in response to the leakage

Component grounding

a grounding method where the ground wire is attached directly to an electrical component such as a receptacle

Component plan

a group of schedules that state the required locations for receptacles, lights, and switches according to the NEC and local codes

Rigid Metal Conduit (RMC)

a heavy-duty pipe that is threaded on the ends much like standard plumbing pipe (limited mainly for to risers for service entrance)

Western Union

a splice that is used when he connection must be strong enough to support long lengths of heavy wire (twist ends facing each other cut off ends)

Fuse

an electric overcurrent protection device used to limit the rate of current flow in a circuit

Receptacle box/junction box and where they must be installed

an electrical device designed to house electrical components and protect wiring connections (installed at every point in the electrical system where NM cable is spliced or terminated) (size matters is based on number and size of the wires)

Crimp connector

an electrical device that is used to join wires together or serve as terminal ends for screw connections

Switch

an electrical device used to stop, start, or redirect the flow of current in an electrical circuit

Conductor symbol

an electrical symbol that represents copper and aluminum respectively

Generator

an electromechanical device that converts mechanical energy into electrical energy by means of electromagnetic induction

Insulator

any material that has a very high resistance and resists the flow of electrons

Split

bolt connector - solderless mechanical connection used for joining large cables

Conventional current flow

current flow from + to -

Wire nuts

designed to hold several electrical wires firmly together and insulated cover on connections. Size is determined by the number and size of wires to be connected. Color coding to indicate the maximum number of conductors allowed per connection, colors vary by manufacturer

Kinetic energy

energy of motion (released potential energy)

National Electrical Code (NEC)

is a book of electrical standards that indicate how electrical systems must be installed and how work must be performed. Standards for residential, commercial, and industrial electrical work

Compression connector

is a box fitting that firmly secures conduit to a box by utilizing a nut that compresses a tapered metal ring into the conduit

Set screw connector

is a box fitting that relies on the pressure of a screw against the conduit to hold the conduit in place

Indentor connector

is a box fitting that secures conduit to a box with the use of a special indenting tool (non-reuseable, hacksawed to remove)

Equipment ground

is a circuit designed to protect individual components connected to an electrical system

Flexible Metal Conduit (FMC)

is a conduit that has no wires and can be bent by hand (used where movement or vibration is present)

Compact fluorescent

is a fluorescent lamp that has a smaller diameter than a conventional fluorescent lamp and a folded bulb configuration

Clip grounding

is a grounding method where a ground clip is slipped over the ground wire from the electrical device

Pigtail grounding

is a grounding method where two ground wires are used to connect an electrical device to a ground screw in the box and then to system ground

Electrode

is a long metal rod used to make contact with the earth for grounding purposes

Fluorescent

is a low-pressure discharge lamp in which ionization of mercury vapor transforms ultraviolet energy generated by the discharge into light

Canadian Standard Association (CSA) label

is a marking that indicates that extensive tests have been conducted on a device by the CSA

Insulator materials

is a material that has a very high resistance an resists the flow of electrons (rubber, plastic, air, glass, and paper)

Wire Marker

is a preprinted peel-off sticker designed to adhere to insulation when wrapped around a conductor (resist moisture oil, and dirt)

Knockout

is a round indentation punched into the metal of a box and held in place by punched narrow strips of metal

Conduit

is a rugged protective tube (typically metal) through which insulated conductors are pulled

System ground

is a special circuit designed to protect the entire distribution system of a residence

UL label

is a stamped or printed icon that indicates that a device or material has been approved for consumer use by Underwriters Laboratories Inc

Substation

is an assemblage of equipment installed for switching,changing, or regulating the voltage of electricity

Transformer (XFMR)

is an electric device that uses electromagnetism to change voltage from one level to another or to isolate one voltage from another

Service panel

is an electrical device containing fuses or circuit breakers for protecting the individual circuits of a residence and serves as a means of disconnecting the entire residence from the distribution system

Automatic transfer switch (ATS)

is an electrical device that transfers the load of a residence from public utility circuits to the output of a standby generator during a power failure

Circuit breaker

is an overcurrent protection device with a mechanical mechanism that may manually or automatically open a circuit when an overload condition or short circuit occur

Manually controlled circuit

is any circuit that requires a person ti initiate an action for the circuit to operate

Potential energy

is stored energy a body has due to its position, chemical state, or condition

Capacitance

is the ability of a component or circuit to store energy in the form of an electrical charge

Voltage (AC only)

is the amount of electrical pressure in a circuit. Produced any time there is an excess of electrons at one terminal and deficiency in an other, the greater the difference = higher voltage

Footcandles

is the amount of light produced by a lamp divided by the area that is illuminated

Splice

is the joining of two or more electrical conductors by mechanically twisting the conductors together of by using a special splicing device

Power formula

is the relationship between Power, Voltage, and Current in an electrical circuit P=ExI

Lumens

is the unit used to measure the total amount of light produces by a light source

In

phase - the state when voltage and current reach their mac amplitude and zero level simultaneously

Single phase

power supply has one distinct wave cycle, single wire, 230V

Nonmetallic

sheathed cable - a type of cable that consists of 3 insulated electrical conductors held together and protected by a strong plastic jacket (info printed on outside)

National Fire Protection Association: NFPA 70E

standard for electrical safety in a workplace, addresses electrical safety requirements for employee workplaces that are necessary for safeguarding employees in pursuit of gainful employment

T

tap - a splice that allows a connection to be made without cutting the main wire (most difficult)

True power (PT)

the actual power used in electrical circuit (watts, W)

Current

the amount of electrons flowing through an electrical circuit (amperes)

Ampere/amp

the number of electrons passing a given point in 1 second

Apparent power (PA)

the product of voltage and current in a circuit calculated without considering the phase shift that may be present between the voltage and current in the circuit (Volt amps, VA)

Inductance

the property of a circuit that causes it to oppose a change in current due to energy stored in a magnetic field

Power (P)

the rate of doing work or using energy

Power factor (PF)

the ratio of true power used in an AC circuit to apparent power delivered to the circuit (PF=PT/PA x 100)

Four way

used in combination with two three-way switches to allow control of a load from 3 locations