Voltage: Electrical pressure that pushes current; measured in volts
Current: Flow of electric charge; measured in amperes
Resistance: Opposition to current; measured in ohms
Power: Rate of using energy; measured in watts
Ohm's law: Volts = amps x ohms
Watt's law: Watts = volts x amps
Conductor: Material that carries current easily, like copper
Insulator: Material that resists current, like rubber
Circuit: A complete path for current
Open circuit: A broken path; no current flows
Short circuit: An unintended low-resistance path causing very high current
Series circuit: Components in one path
Parallel circuit: Components on separate branches
AC: Alternating current, which changes direction
DC: Direct current, which flows one way
Hot wire: Carries current from the source; usually black or red
Neutral wire: Returns current to the source; usually white
Ground wire: Safety path to earth; bare copper or green
Circuit breaker: Switch that opens automatically when current is too high
Fuse: A safety device with a link that melts on overcurrent
GFCI: Ground fault circuit interrupter, which cuts power when current leaks
AFCI: Arc fault circuit interrupter, which guards against arcing
Panel (breaker box): Enclosure holding circuit breakers
Service entrance: Where utility power enters a building
Meter: Device measuring electricity use
Receptacle: Outlet where plugs connect
Switch: Device that opens and closes a circuit
Three-way switch: Allows control of a light from two places
Junction box: Enclosure for wire connections
Conduit: Protective tube for wiring
EMT conduit: Electrical metallic tubing, a thin-walled metal conduit
Romex: Common brand name for non-metallic sheathed cable
Wire gauge (AWG): Size of wire; a smaller number means thicker wire
14 AWG wire: Commonly used on 15-amp circuits
12 AWG wire: Commonly used on 20-amp circuits
Ampacity: Maximum current a conductor can carry safely
Voltage drop: Loss of voltage along a wire
Wire nut: Cap used to join wires
Lug: A connector point for a wire
Terminal: A screw or clamp point where wire attaches
Strip: Remove insulation from a wire end
Pigtail: A short wire used to connect multiple wires to one terminal
Load: A device that uses electrical power
Line side: The side of a device connected to the power source
Load side: The side leading to the devices
Multimeter: Tool measuring voltage, current and resistance
Voltage tester: Tool that detects live circuits
Lockout/tagout: Safety procedure keeping a circuit off while working on it
NEC: National Electrical Code, setting US wiring standards
Permit: Official permission to do regulated electrical work
Inspection: Official check that work meets code
Journeyman electrician: A licensed electrician who has completed an apprenticeship
Master electrician: A highly experienced, licensed electrician
Apprentice: A trainee learning the trade on the job
Transformer: Device that changes voltage levels
Step-down transformer: Reduces voltage
Motor: Device converting electrical energy to motion
Capacitor: Component that stores charge
Relay: A switch operated by an electromagnet
Contactor: A heavy-duty relay for high-current loads
Phase: One of the alternating currents in a power system
Single-phase: Power common in homes
Three-phase: Power common in industry
120 volts: Standard household outlet voltage in the US
240 volts: Higher household voltage for appliances like dryers
Frequency: Cycles per second; 60 Hz in the US
Kilowatt-hour: A unit of energy used on electric bills
Load calculation: Figuring the total power demand of a building
Overcurrent: More current than a circuit is designed to carry
Arc flash: A dangerous explosion of energy from an electrical fault
Electrical shock: Current passing through the body; potentially deadly
PPE: Personal protective equipment, such as insulated gloves
Bonding: Connecting metal parts to make them electrically continuous
Grounding electrode: A rod or pipe that connects the system to the earth
Dimmer: A switch that varies light brightness
Smart switch: A switch controlled by an app or voice
Solar panel: Device turning sunlight into DC electricity
Inverter: Converts DC power to AC
Surge protector: Device limiting voltage spikes
Extension cord rating: Must match or exceed the load's amperage
Knockout: A removable circle in a box for cable entry
Fish tape: A tool for pulling wire through walls and conduit
Lineman's pliers: Heavy pliers for cutting and twisting wire

Free flashcards from Peabody at peabody.kids/flashcards/tp-trades-electrical