Electrical terms,
plain English.

The unit of electrical current. A 20-amp circuit can safely carry 20 amps of current continuously. Your home's service size (100A, 200A) refers to the maximum amperage available from the utility.

A type of circuit breaker or outlet that detects dangerous arcing in wiring and shuts the circuit off before a fire starts. NEC 2020 requires AFCI protection in most living areas. Standard breakers don't detect arcing.

The type of electricity delivered by utilities and used in homes and businesses. Current reverses direction 60 times per second (60Hz) in the US. Contrast with DC (Direct Current), used in batteries and electronics.

The practice of connecting all metal components in an electrical system together so they share the same electrical potential. Prevents dangerous voltage differences between metal surfaces. Different from grounding but works alongside it.

A circuit that runs from the panel to one or more outlets, lights, or appliances. Every circuit in your home is a branch circuit. Kitchen circuits, bedroom circuits, and appliance circuits are all branch circuits.

The metal bar inside your electrical panel that distributes power from the main breaker to individual circuit breakers. Hot (black) wires connect to the hot bus bar; neutral (white) wires connect to the neutral bus bar.

A safety device that automatically shuts off power to a circuit when it detects an overload or short circuit. Designed to be reset after tripping. A breaker that trips repeatedly is protecting you — don't keep resetting it without diagnosing the cause.

Any material that allows electricity to flow through it. In home wiring, conductors are typically copper or aluminum wires inside insulation. The term also refers to any specific wire carrying current.

A protective tube — metal (EMT, rigid) or plastic (PVC) — through which electrical wires are run. Required in exposed locations like garages, basements, and outdoor runs. Protects wires from physical damage.

A panel or outlet cover that prevents accidental contact with live electrical parts. A properly installed panel has a dead front cover that must be removed to access breakers or wiring.

A circuit that serves only one appliance or outlet — not shared with any other device. Refrigerators, dishwashers, EV chargers, microwaves, and electric ranges each require a dedicated circuit.

A utility billing component based on the peak electrical demand (highest 15 or 30-minute average) during a billing period. Commercial customers pay demand charges — a key reason smart load management matters for EV fleet charging.

Electrical current that flows in one direction only — as in batteries and solar panels. DC Fast Charging (DCFC) for EVs converts AC grid power to DC before it enters the vehicle. Most home and commercial power is AC.

Another term for your electrical panel or load center — the box that distributes power from the utility service to individual circuits in your home or building.

A standby generator that can run on either natural gas or propane — switchable between fuel sources. Offers flexibility in areas where one fuel type may be unavailable or interrupted.

Electric Vehicle Supply Equipment — the technical term for an EV charging station. Includes the hardware, wiring, and control electronics that supply power from your electrical system to a vehicle's onboard charger. Commonly called an "EV charger."

Unintended current flowing through an unintended path — such as through a person, ground, or short circuit. Circuit breakers, GFCIs, and AFCIs are all designed to detect fault current and interrupt the circuit.

A large circuit that runs from the main panel to a subpanel or other distribution point. The wires running from your home's main panel to a detached garage subpanel are feeders.

A unit of illuminance — how much light falls on a surface. One footcandle equals the light from one candle at one foot distance. Parking lot lighting standards typically specify minimum footcandle levels for safety.

Ground Fault Circuit Interrupter — an outlet or breaker that detects current leakage to ground and shuts off power in milliseconds, preventing electrocution. Required by code in bathrooms, kitchens, garages, outdoor areas, and other wet locations. Test them monthly.

A safety conductor — typically bare copper or green insulation — that provides a path for fault current to flow safely to ground rather than through people or equipment. The ground wire in a 3-prong outlet is the round bottom pin.

Connecting electrical equipment to the earth (ground) through a conductive path. Prevents dangerous voltage buildup on equipment enclosures and provides a fault current path that trips breakers. Requires both a ground rod and bonding throughout the system.

A copper-clad steel rod driven into the earth to establish a grounding connection for your electrical system. Most homes require at least two ground rods. Part of the grounding electrode system.

The unit of frequency — cycles per second. US electrical power runs at 60Hz (alternating current reverses direction 60 times per second). Most of the world uses 50Hz. Equipment rated for one frequency may not work correctly on the other.

The energized conductor that carries current from the panel to an outlet or device. In standard US wiring, the hot wire has black insulation. In a 240V circuit, there are two hot wires (black and red). Never touch a hot wire without de-energizing and verifying.

Heating, Ventilation, and Air Conditioning. HVAC systems are major electrical loads — central AC typically requires a 240V dedicated circuit and is a common reason for panel upgrade needs.

The non-conductive coating around electrical conductors that prevents accidental contact with live parts. Insulation degrades over time due to heat, moisture, and physical damage. Damaged insulation is a fire hazard.

A device that converts DC power to AC power — used in solar systems, battery storage (like Tesla Powerwall), and UPS systems. Some EV chargers also use inverter technology.

An enclosure where wires are joined (spliced) together. All wire splices must be inside a covered junction box per NEC — never in a wall cavity. Junction boxes provide access for future repairs and protect connections from physical damage.

A unit of electrical power equal to 1,000 watts. Used to describe the capacity of generators, EV chargers, and large electrical loads. A 7.2kW Level 2 EV charger delivers 7,200 watts of power.

The unit of electrical energy used for utility billing. One kWh equals 1,000 watts used for one hour. If you run a 1,000W device for 10 hours, you've used 10 kWh. Average KC residential rate is approximately $0.10/kWh.

Pre-cut circular openings in electrical boxes and panels that can be removed to accept conduit or cable connectors. Knockouts that aren't used must be covered to maintain the enclosure's protection rating.

EV charging using a standard 120V household outlet. Delivers approximately 3–5 miles of range per hour of charging. Suitable for plug-in hybrids or drivers with very low daily mileage. No installation required.

EV charging using a 240V dedicated circuit. Delivers approximately 20–35 miles of range per hour. The most common home and workplace charger type. Requires professional installation of a 240V circuit and EVSE.

Any device or appliance that consumes electrical power. Calculating the total load on a circuit or panel determines whether capacity is sufficient. Electricians perform load calculations to size panels and service upgrades.

Another name for your main electrical panel. The load center distributes electrical power from your service entrance to individual circuits throughout the home or building.

Software and hardware that dynamically distributes available electrical capacity among multiple EV chargers or loads. Allows more vehicles to charge simultaneously without requiring a larger electrical service — critical for fleet charging economics.

The unit of luminous flux — how much total light a source produces. A standard 60W incandescent bulb produces about 800 lumens. An equivalent LED produces the same 800 lumens using only 8–10W.

The large double-pole breaker at the top of your service panel that controls power to all circuits in the panel. Turning it off disconnects all circuits from the utility supply. Rated in amperes — 100A, 200A, 400A.

The enclosure where the utility meter connects to your home's electrical system. Located at the point of utility service entry. Meter socket upgrades are sometimes required during panel upgrades.

National Electrical Code — the standard for safe electrical installation in the United States, published by NFPA. Updated every 3 years. Local jurisdictions adopt the NEC with or without amendments. All licensed electrical work must meet the applicable NEC edition.

The conductor that completes the circuit by carrying current back to the panel from outlets and fixtures. In standard wiring, the neutral has white insulation. The neutral wire is connected to the neutral bus bar in the panel.

The National Fire Alarm and Signaling Code — the standard governing the design, installation, testing, and maintenance of fire alarm systems. Annual inspections and written documentation are required under NFPA 72.

The Standard for Electrical Safety in the Workplace — governs electrical safety practices for workers, including arc flash hazard analysis, PPE requirements, and lockout/tagout procedures. Required for industrial electrical work.

A condition where more current flows through a conductor than it's rated to carry. Circuit breakers and fuses protect against overcurrent by interrupting the circuit before conductors overheat and create a fire hazard.

A condition where a circuit carries more current than it's designed for — typically from too many devices running simultaneously. Causes the circuit breaker to trip. Solution: redistribute loads or add a dedicated circuit.

Authorization from the local Authority Having Jurisdiction (AHJ) to perform specific electrical work. Permits ensure work is inspected for code compliance. Required for panel upgrades, new circuits, EV charger installations, and most significant electrical work. Pure Light Electric handles all permit applications.

In electrical systems, phase refers to how the alternating current cycles are timed. Most homes have single-phase power. Commercial and industrial facilities typically have three-phase power, which delivers more power more efficiently and is required for large motors and equipment.

Any enclosed channel designed to hold electrical wires — including conduit, cable trays, wireways, and similar systems. All raceways must be properly supported and sealed to protect conductors and maintain code compliance.

The point where utility power enters your home — including the service drop (overhead) or lateral (underground), meter socket, and service entrance conductors to the main panel. Service entrance upgrades are part of panel upgrades.

The main electrical panel in your home — also called a load center, breaker box, or distribution panel. Contains the main breaker and all individual circuit breakers. Rated by amperage (100A, 200A, 400A).

A fault that allows current to flow through an unintended path of very low resistance — typically when a hot wire contacts a neutral or ground wire. Creates a massive current surge that trips the breaker. A repeated short circuit requires immediate diagnosis.

The standard electrical service for most residential buildings — two hot conductors (120V each, 240V between them) plus a neutral. Contrasted with three-phase service used in commercial and industrial facilities.

Surge Protective Device — a panel-mounted or point-of-use device that diverts excess voltage (from lightning, utility switching, or other transients) to ground before it can damage equipment. A whole-home SPD protects every circuit simultaneously.

A secondary electrical panel fed from the main panel. Used to distribute power to a specific area — detached garage, basement, addition, or ADU. Allows circuit capacity where it's needed without running individual circuits from the main panel.

An electrical system with three hot conductors, each 120° out of phase with each other. Delivers power more efficiently for large motors and industrial equipment. Common in commercial buildings and required for many industrial applications.

A device that switches an electrical load between two power sources — typically utility power and a generator. An Automatic Transfer Switch (ATS) detects an outage and switches automatically. Required for all permanently installed generators.

Certified by Underwriters Laboratories — a safety certification indicating a product has been tested and meets established safety standards. All electrical equipment installed by licensed contractors should be UL listed or similarly certified.

The unit of electrical pressure (voltage). Standard US outlets are 120V. Large appliances and EV chargers use 240V. Voltage drives current through a circuit — higher voltage means more "push" for the same load.

A tool that measures voltage between two points in a circuit. Used by electricians to verify circuit voltage, check for live wires, and diagnose faults. A basic safety tool before working on any circuit.

The unit of electrical power — calculated as Volts × Amps. A 120V outlet drawing 10A delivers 1,200W. A 240V EV charger circuit at 32A delivers 7,680W (7.68kW).

American Wire Gauge — the standard sizing system for electrical wires. Counter-intuitively, lower gauge numbers mean thicker wire. 14 AWG is standard for 15A circuits; 12 AWG for 20A circuits; 10 AWG for 30A circuits; 6 AWG for EV charger circuits.