AFCI
A special breaker that watches for dangerous sparks inside wiring that you cannot see. Sparking usually happens when cords are damaged, wires loosen, or nails/screws hit wires in walls. Regular breakers cannot detect this. AFCI breakers shut the power off before a spark becomes a fire.
AMPS
A measurement of how much electricity is flowing through a circuit at one time. Think of it like the “amount of water” moving through a pipe. Every wire and breaker is designed to handle only so many amps. Too many amps causes heat and trips breakers.
Backfed Breaker
A breaker that is connected so power flows into the panel through the breaker instead of out to a branch circuit. Backfed breakers are most commonly used for generators or solar systems and must be properly secured in the panel so they cannot be removed while energized.
Bonding
The act of connecting metal parts of a home so they are all electrically linked together. This prevents metal from building up different electrical charges. If a fault occurs, the electricity travels safely back to the panel instead of shocking someone. Bonding applies to water pipes, gas pipes, metal boxes, and equipment.
Branch Circuit
A wiring path that sends electricity from the breaker panel to a room or device. Each branch circuit has its own breaker designed for the outlets, lights, or appliances it powers. Modern code requires some rooms (kitchens, bathrooms, laundry) to have multiple dedicated branch circuits.
Breaker
A switch designed to shut off automatically if a circuit becomes unsafe. Breakers protect wires from overheating by stopping electricity when too much current flows. They prevent house fires and equipment damage.
Cable
A group of insulated wires wrapped in a protective outer jacket. Cable allows multiple conductors (hot, neutral, ground) to run together safely behind walls. Different sizes of cable are used depending on how much power the circuit needs.
Circuit
A complete loop that electricity travels through. Power leaves the panel through a hot wire, runs through lights or devices, and returns on the neutral wire. If any part is broken or interrupted, the circuit stops working.
Combo Breaker
A breaker that includes both AFCI and GFCI protection in one device. This means it watches for sparks (arcs) and for shock hazards (ground faults). These are becoming required in many rooms as code modernizes.
Conduit
Tubing that shields and guides electrical wires, typically in garages, concrete walls, or outdoors. Conduit protects wires from physical damage, pests, sunlight, and moisture. It also keeps wiring organized and accessible for future changes.
Continuity
A measurement that shows whether electricity can travel unbroken through a wire, switch, or device. If continuity is lost, power cannot flow. Electricians test continuity to locate broken wiring or failed components.
Dedicated Circuit
A circuit designed to power only one appliance. Large appliances like microwaves, refrigerators, and air conditioners require their own circuits so they do not overload shared wiring.
Disconnect
A manual switch that shuts off power to a specific device or entire service. Common disconnects are found near air conditioners, spas, well pumps, or outside near the meter. They allow a tech to safely work without live power.
EMT
Electrical Metallic Tubing, also called thin-wall conduit. Lightweight metal tubing used to protect wiring on surfaces like garage walls or commercial buildings. It bends easily and provides physical protection.
Feeder
Wiring that carries power from one electrical panel to another location. Feeders are larger wires than branch circuits because they supply multiple circuits downstream. Examples include power to a detached garage, shed, or subpanel.
Fixture
A permanently installed lighting device connected directly to building wiring. Fixtures are different from plug-in lamps because they are part of the home’s electrical system. They must be properly supported and wired to a junction box for safety.
Fuse
A safety device used before modern breakers. A fuse contains metal that melts and opens the circuit when too much current flows. Once a fuse melts, it must be replaced instead of being reset like a breaker. Many older homes still use them.
GFCI
A device that protects people from shock by turning off power if it senses electricity leaking to ground. Required near water: kitchens, bathrooms, garages, outside outlets.
Ground
A safety path that directs stray electricity safely into the earth. Grounding prevents metal surfaces and appliances from becoming energized if something fails. It also gives breakers a path to react and shut off power.
Ground Rod
A metal rod driven deep into the soil and connected to the house grounding system. It provides a physical connection to earth for fault current, lightning energy, and other abnormal electrical events. Most homes require one or two rods.