Electrician Journeyman Flashcards
Flashcards
Term
Definition
Ampacity
The maximum current a conductor can carry continuously without exceeding its temperature rating.
Capacitor
A component that stores electrical energy in an electric field.
Relay
An electrically operated switch used to open or close a circuit.
Direct Current (DC)
Electric current that flows in only one direction.
Watt
Unit of electrical power equal to one joule per second.
Volt
Unit of electrical potential difference or pressure.
Ampere
The unit of electric current, equivalent to one coulomb per second.
Circuit
A complete path for current to travel from source to load and back.
Admittance
The ease with which current flows, measured in siemens.
Current
The flow of electric charge in a conductor.
Diode
A semiconductor device that allows current to flow in only one direction.
Fuse
A protective device that melts to break a circuit when current is too high.
Frequency
The number of AC cycles per second, measured in hertz (Hz).
Generator
A machine that converts mechanical energy into electrical energy.
Hertz
Unit of frequency, one cycle per second.
Inductance
The property of a conductor to resist a change in current, measured in henries.
Impedance
Total opposition to alternating current, including resistance and reactance.
Ohm
The unit of electrical resistance.
Power
The rate at which energy is used or transferred, measured in watts.
Resistance
The opposition to the flow of electric current, causing heat.
Transistor
A semiconductor device used to amplify or switch electronic signals.
Alternating Current (AC)
Current that periodically reverses direction.
Ambient Temperature
Temperature of the surrounding environment.
Ammeter
Instrument for measuring current in a circuit.
Box Fill
The number of conductors/devices permitted in an electrical box.
Branch Circuit
Circuit from the final overcurrent device to the outlets.
Busbar
A conductive bar for distributing electricity inside a panel.
Code Violation
An installation that fails to meet NEC requirements.
Dead Front
Panel design with no exposed live parts.
Demand Factor
Ratio of actual load to maximum possible load.
Derating
Reduction of ampacity due to conditions like temperature.
Disconnect Switch
A switch used to isolate electrical equipment.
Distribution Panel
Main point where electrical power is divided into circuits.
Diversity Factor
Used to reduce total load when not all devices run simultaneously.
Electrical Load
Total power consumed by a system.
EMI
Electromagnetic interference affecting signal transmission.
EER
Energy Efficiency Ratio, rating HVAC performance.
Farad
The unit of capacitance.
Fault Current
Current flowing through an abnormal fault path.
Ground Rod
Electrode driven into the earth for grounding.
High-Resistance Grounding
Limits fault current using resistors.
Inductive Load
Load that causes phase shift due to magnetic field (e.g., motor).
kWh
Kilowatt-hour, unit of energy consumption.
Lighting Load
The power demand of lighting systems.
LOTO
Lockout/Tagout safety procedure.
Megger
Device for testing insulation resistance.
NFPA
National Fire Protection Association, NEC publisher.
Overload Protection
Prevents excessive current in normal operation.
Parallel Circuit
Multiple current paths; voltage is the same.
Phase
The time difference between multiple AC waveforms.
Photovoltaic System
Solar panels converting sunlight to electricity.
Plenum
Building space used for air circulation requiring special cables.
Power Factor
Ratio of real power to apparent power.
Service Entrance
Point where utility power enters a building.
Series Circuit
One current path; voltage is divided.
Single-Phase Power
AC power with one alternating voltage.
Stray Voltage
Unexpected voltage due to grounding or wiring issues.
SPD
Surge Protection Device against voltage spikes.
Three-Phase Power
AC power system with three voltage waveforms.
Transformer
Device that steps voltage up or down.
Voltage
Potential difference driving current through a circuit.
Wire Nut
Twist-on connector for joining wires.
GFCI
Protects against ground faults by cutting off current.
NEC
National Electrical Code, standard for electrical safety.
Service Panel
Main distribution point for electrical circuits.
Romex
Trade name for NM cable used in residential wiring.
THHN
Thermoplastic High Heat-resistant Nylon-coated wire.
Ground Fault
Unintended electrical path to ground.
Breaker Panel
Panel housing multiple circuit breakers.
Overcurrent
Excess current exceeding rated value.
Conduit
Tube protecting and routing electrical wires.
AWG
American Wire Gauge, standard for wire size.
Insulator
Material that resists electric current.
Conductor
Material allowing current to flow.
Short Circuit
Abnormal connection with low resistance.
Load Center
Panel for distributing power to branch circuits.
Receptacle
Outlet for plugging in electrical devices.
Neutral
Returns current to source in AC systems.
Hot Wire
Live conductor carrying current from source.
Green Wire
Used for equipment grounding.
Bonding
Connecting conductive parts to ensure continuity.
Knockout
Removable section in boxes/panels for conduit.
Box Connector
Secures cable/conduit to a box.
Feeder
Conductors supplying power to a panel.
Voltage Drop
Loss in voltage over a conductor run.
Device Box
Enclosure for switches or outlets.
MC Cable
Metal-clad cable used in commercial wiring.
UF Cable
Underground Feeder cable.
AFCI
Arc Fault Circuit Interrupter.
NEMA
National Electrical Manufacturers Association.
Wire Gauge
Size rating of electrical wire.
Multimeter
Device measuring voltage, current, resistance.
Ohmmeter
Measures resistance in ohms.
Wattmeter
Measures power consumption in watts.
Grounding Electrode
Connection to earth for fault current.
Load
Device using electrical energy.
Line
Conductors supplying power to load.
Circuit Breaker
Device protecting circuit from overcurrent.
Disconnect
Manual switch to isolate power.
Lug
Connector for terminating conductors.
Splice
Joining two conductors.
Continuity
Unbroken electrical path.
AC Voltage
Voltage that alternates polarity.
DC Voltage
Voltage with constant polarity.
Clamp Meter
Measures current using a clamp around wire.
Step-down Transformer
Lowers voltage from primary to secondary.
Step-up Transformer
Increases voltage from primary to secondary.
Load Calculation
Determining expected electrical demand.
Demand Load
Load used for sizing electrical systems.
Main Breaker
Primary overcurrent device in a panel.
Neutral Bus
Terminal for connecting all neutral wires.
Ground Bus
Terminal for grounding wires.
Voltage Rating
Maximum voltage equipment can handle.
Amp Rating
Maximum current a device can carry.
Receptacle Rating
Current and voltage limits of an outlet.
Box Fill Calculation
Number of wires allowed in a box.
Tamper-Resistant Receptacle
Outlet with safety shutters.
Weatherproof Cover
Protective outlet cover for outdoor use.
Backstab
Quick push-in wire connection method.
Wire Strip Gauge
Guide for removing insulation.
Grommet
Protective ring for cable holes.
Raceway
Enclosed conduit for electrical conductors.
Flexible Conduit
Bendable conduit for wiring.
Liquidtight
Conduit suitable for wet locations.
Voltage Tester
Tool to detect presence of voltage.
Pigtail
Short wire joining multiple conductors.
120/240V System
Common US residential voltage setup.
Service Disconnect
Main shutoff for utility power.
Load Side
Part of circuit after overcurrent device.
Line Side
Part of circuit before overcurrent device.
Overhead Service
Power from pole via wires above ground.
Underground Service
Power enters property below ground.
Voltage Rating of Cable
Max voltage cable can safely carry.
Electrical Permit
Authorization for electrical work.
Inspector
Verifies code compliance on installations.
AHJ
Authority Having Jurisdiction.
Annex A
NEC list of product safety standards.
Annex B
Guidance for ampacity calculations.
Annex C
Conduit and cable fill tables.
Annex D
Examples for load calculation.
Annex E
Construction types.
Annex F
Critical operations power systems.
Annex G
SCADA supervisory systems.
Annex H
Administration and enforcement.
Annex I
Recommended torque values.
Annex J
ADA accessibility design.
Annex K
Use of medical equipment in dwellings.
