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Ground School · Reference

The Electrical Glossary

22 electrical terms in plain English — every word you'll see in a quote, an inspection report, or a Top Flight Learning Center guide.

A
AFCI (Arc-Fault Circuit Interrupter)
A breaker or outlet that detects the electrical signature of arcing — sputtering current from damaged wires or loose connections — and cuts power before the arc can start a fire. Modern code requires AFCI protection on most living-area circuits. GFCI vs AFCI, explained →
Amperage (Amps)
The measure of electrical current flow. Your main breaker's amp rating (100, 150, 200) is the total your home can draw at once; each branch breaker limits its own circuit to what the wiring behind it can safely carry. How your panel works →
Arc Fault
Electricity jumping a gap it shouldn't — across a damaged wire, a loose termination, or a nail through a cable. Arcs generate intense localized heat and are a leading cause of electrical fires, often without ever tripping a standard breaker.
Automatic Transfer Switch (ATS)
The device that lets a standby generator take over from utility power automatically — and, critically, makes it physically impossible for generator and utility power to feed the same wires at once. Generator buying guide →
B
Backfeeding
Illegally feeding generator power into home wiring through an outlet (like a dryer receptacle) without a transfer switch. It can energize the utility line outside your home and electrocute line workers — never do this.
Branch Circuit
One protected path from a breaker to a set of outlets, lights, or an appliance. General-purpose circuits are typically 15 or 20 amps; large appliances get dedicated circuits sized to their load.
Breaker (Circuit Breaker)
A resettable switch that automatically cuts power when a circuit carries more current than its wiring is rated for. Breakers protect the wire, not the appliance — which is why 'upgrading' a breaker without upgrading the wire is dangerous. Why breakers trip →
D
Dedicated Circuit
A circuit serving exactly one appliance — range, dryer, AC, EV charger, microwave. Required for high-draw equipment so its startup and running load can't starve or trip anything else.
Double-Tap
Two circuit wires landed under one breaker terminal designed for one. A common inspection finding in full panels; it causes loose connections and heat, and usually signals the panel is out of space.
G
GFCI (Ground-Fault Circuit Interrupter)
A device that compares outgoing and returning current and trips in milliseconds when even a few milliamps leak — the threshold that protects people from shock. Required wherever water and electricity share a room. GFCI vs AFCI, explained →
Grounding
The system that gives fault current a safe, low-resistance path to earth so breakers trip fast and metal surfaces can't stay energized. Ungrounded (two-prong) circuits are common in pre-1960s homes and have modern remediation paths.
L
Level 2 Charging
EV charging on a 240-volt circuit, adding roughly 20–40+ miles of range per hour. Requires a dedicated circuit sized by a load calculation — it's among the largest continuous loads in a modern home. Home EV charger guide →
Load Calculation
The code-prescribed math that adds up a home's square footage, appliances, HVAC, and large loads (with demand factors) to determine what service size it needs. The honest basis for any panel-upgrade recommendation. Panel upgrade guide →
M
Main Breaker
The large breaker at the top of your panel that limits total household draw and shuts off everything downstream. Its rating (100/150/200) is your service size — and knowing where it is matters in an emergency.
N
NEC (National Electrical Code)
The model electrical code adopted (with state amendments) by Florida. It sets the safety requirements for wiring, protection, and equipment; 'to code' means to the edition in force when the work is permitted.
P
Panel (Load Center / Breaker Box)
The metal cabinet where utility power is divided into branch circuits, each protected by a breaker. Its capacity, condition, and brand history determine most of what's possible — and safe — in your electrical system. How your panel works →
Permit (Electrical)
The municipal authorization and inspection that accompanies significant electrical work in Florida — panel changes, new circuits, service upgrades. Pulled by the licensed contractor; a bid that skips it is a red flag, not a savings. How to vet an electrician →
S
Service Drop / Weatherhead
The overhead utility conductors reaching your home and the mast fitting where they enter. Trees into the drop and water past the weatherhead are two of the most common storm-season service problems.
Short Circuit
A hot conductor touching neutral or another hot, sending current on an unintended low-resistance path. Current spikes instantly and the breaker should trip immediately — a short never fixes itself. Why breakers trip →
Surge Protective Device (SPD)
A panel-mounted device that clamps voltage spikes from lightning activity and grid events before they reach branch circuits. The first layer of surge defense in lightning-heavy Central Florida; point-of-use protectors are the second. Surge protection guide →
T
Transfer Switch (Manual)
A licensed-installed switch that lets a portable generator safely power selected circuits through an exterior inlet — the code-compliant alternative to extension cords, and the safety heart of any portable backup setup. Generator buying guide →
V
Voltage (120V / 240V)
US homes receive two 120-volt legs. Standard outlets use one leg (120V); large appliances — dryers, ranges, AC, EV chargers — bridge both (240V). Losing one leg after a storm makes exactly half the house go dark.
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