Electrical Glossary


A-Line Lamp: An indoor lamp regularly used in residential homes.

Accent Lighting: Bright, specifically placed lighting used to accent certain parts of residential homes.

Alternating Current (AC): A current of electricity that changes direction according to frequency.

Alternator: A generator that producing a constant alternating electrical current.

Ambient Lighting: General lighting used in resident and commercial areas.

American Wire Gauge (AWG): A standard measurement system to rate the size of electrical wire.

Ampacity: Maximum amount of current that a conductor can carry continuously.

Ampere: An electrical current that is created when one ohm is applied to one volt.

Analog: The standard unit of measure assessing physical restrictions.

Arc Tube: A clear, glass tube made of quartz that houses an arc stream.


Ballast: A limited electrical current device that works to run fluorescent lighting.

Ballast Cycling: When fluorescent lighting cycles on and off to avoid overheating.

Battery: A unit that houses two or more cells that connect to create an electrical current.

Blower Doors: A device used to send a wind current though residential homes and make leaks around doors, windows and other areas become apparent.

Branch Circuit: Circuits that feed devices, appliances and other electrical needs in a residence.

Brownout: A decrease in available power when the generation of electricity cannot keep up with demand.

BTU (British Thermal Unit): Standard unit for measuring heat quantities.


Cable Lighting System: A hanging track wiring system of low voltage spot lighting.

Candlepower/Candela: Unit of measure for light intensity.

Capacitor: Electronic component that holds an electrical charge.

Cathode: An electrode that emits electrons out of a device.

Cell: The part of a battery that converts chemical energy into a working electrical current.

Circuit Breaker: A device designed to control electrical currents without ruining the wiring.

Circuit Extensions: An extension to a circuit that provides an additional power source.

Code Corrections: A citation issued to correct wiring that does not meet required safety regulations.

Colored Glass Filter: Color inserted directly into glass during the forming process, instead of coated after the glass has cooled.

Color Temperature: Range of measurement from warm colors to cool colors, used to measure the color appearance of a light source.

Compact Fluorescent Lamp (CFL): Small, tube shaped fluorescent lighting with a high color illumination.

Constant Wattage (CW) Ballast: Occurs when a primary and secondary coil is isolated in an HID ballast.

Continuous Load: The maximum electrical load current for a whoy is excepted to run a constant 3+ hours.

Contrast: The range of illumination from light and dark.

Controller: The regulator of electricity between the origin of power and the device it is running.

Cornice Lighting: Bar-shaped fixtures that cover ceiling lighting.

Cover Lighting: a ceiling mounted light used to distribute light across an area.

Current: The flow of electricity.

Cut-off Angle: the angle at which the light from a lamp is not visible.


Daylight Compensation: A dimming lighting system that dims at the presence of natural daylight.

Diffuse: Disillusion of light so that it’s softened around an area.

Dimmer: Used to vary the light distributed by a lamp.

Diode: Device used to allow electricity to flow in one direction.

Direct Current (DC): Power rating that allows the current to flow in one direction.

Downlight: Light mounted in a ceiling that is used to direct light downwards.


Efficacy: Term used to measure light produced vs. energy consumption.

Electroluminescent: A new technology used to provide long lamp life in which consumes very little energy.

Electric Resistance Heating: A heating system the creates heat by passing an electrical current through a conductor.

EMI (Electromagnetic Inference): Interference caused by an electronic component that hinders the operation of electrical equipment.

Emergency Lighting: Lighting that illuminates during a power outage or other emergency.

Energy: A unit of measure for mechanical work, measured in kilo-watt hours.

Energy Efficiency Ration (EER): A ratio comparing the rate at which an air conditioner cools to the total wattage of electrical input.

Energy-Saving Ballast: A efficiently performing magnetic ballast.


Fault: A hiccup in an electrical system causing a short circuit.

Filament: The wire within a light bulb that illuminates when electricity is ran through it.

Flexible Track Lighting System: A lighting system on a track that has the ability to be adjusted.

Fluorescent Lamps: Lights that produce light when electricity is passed through gas rather than a wire.

Foot-Candle: A unit of measurement used to measure the amount of light reaching an object.

Four-Way Switch: Three light switches all wired to control a single lighting system.

Frequency: Rate in which a current changes it’s direction.


Generator: Rotating copper wheel that generates electricity.

Glare: An effect caused by direct light entering the eye.

Grid: A network of wires used to distribute electricity.

Ground: Used to direct electricity to a safe location.


Halogen Lamp: A bulb that contains halogen gases to slow the evaporation of the filament.

Hard Wired: A permanent connection to an electrical source.

Hertz: Measurement of frequency.

HID Lamp: High Intensity lamps with an extensive lifespan.

High Bay: Ceiling lighting where the ceiling exceeds a height of 20 feet.

High Output (HO): A lighting system designed to function with higher currents to put out more light.

High-Tech Troubleshooting: A testing system to identify and wiring system issues or failures.

Horsepower: A unit of power that is equivalent to 746 watts.

Hot Restart/Hot Restrike: The action of a HID light source automatically restarting following a loss in power.


Illuminance (Light Level): The amount of light in a particular room or on an object or surface.

Impulse: A temporary electrical current surge.

Incandescent Light Bulbs: Light bulbs specially made to run electricity through a thin layer.

Infared Cameras: Cameras that pick up on any heat source.

Infared Radiation: An invisible radiation that has extended wavelengths.

Instant Start: Fluorescent lamps that function without requiring preheating.

Insulation: Materials used to resist electrical currents.

Inverter: A device that converts an direct electrical current into an alternative one.

Ion: A molecule or atom that is either positively or negatively charged.


Joule: Unit of measure for potential electrical current equal to 1,000 volts.


Kilovolt (kV): A unit of electrical current equal to 1,000 volts.

Kilowatt (kW): Power delivered in a load.

Kilowatt-hour: Measurement comparison for a unit to energy to one kilowatt for one hour.


Layers: The layers of illumination created by multiple light sources.

LED: An energy-efficient light that has an extremely extensive lifespan.

Light Loss Factor (LLF): An allowance that lets lighting systems in less than ideal conditions.

Light Trespass/Spill Light: The lighting of an unintended area.

Life Cycle Cost: The overall cost of buy and operating a total system over the total lifespan.

Limit Switch: A switch that causes an alteration to an electrical current.

Liquid-Filled Transformer: A liquid that cools and insulates a submerged transformer.

Live Parts: Components of electrical wiring that are exposed and deemed dangerous.

Load: The power supplied by an electrical device.

Loadbreak: The successful avoidance of disengaging a load with damaging it’s components.

Load Center: The power center that distributes power to an entire structure.

Load Curve: Electronic demand vs. Time.

Load Factor: A unit of measure for an electrical system’s capacity and efficiency.

Load Switching: Taking one load and transferring it from one source to another.

Louver: A opaque screen created to minimize glare.

Low Voltage: A wiring system that provides electricity to a device under 100 volts.

Lumen: Unit of measure that indicates the amount of light emitted from a light source.

Luminaire: A light system or single fixture.


Mercury Vapor Lamp: A lamp in which light is produced from the radiation of mercury vapor.

Metal Enclosed/Metalclad: A metal casing that surrounds a device.

Metal Halide: A lamp in which light is produced by the radiation of metal halide.

Motors: The device that moves or runs a system.


National Electrical Code: The code of requirements for proper electrical practices and procedures.

Neodymium: A metal used to create a purple-hued glass for certain light bulbs, goggles, filters and lenses.


Occupancy Sensor: An motion sensor light switch system.

Ohm: Unit of measure to properly measure resistance.

Opaque: A material that does not allow light to pass through at all.

Outlet: A current that is borrowed to supply electricity to somewhere outside of the orginally intended power grid.

Overload: An excessive amount of stress on a particular circuit.

Overvoltage: A voltage that is above the recommend capacity.


PAR Lamp: An aluminium reflector lamp.

Pendant: A glare-deflecting shade for ceiling-mounted lamps.

Phase: An AC circuit classification.

Photocell: Device that senses light and controls the lighting system accordingly.

Power: The unit of measure for energy transferred.

Power Outlet: A device intended to distribute power temporarily to other equipment.

Preheat: The heating up of a fluorescent lamp before the use of high voltage.

Puncture: A discharge that temporarily disrupts a solid dielectric.


Radio Frequency Inference (RFI): The disruption of a radio frequency band by another frequency band nearby.

Rapid Start: A fluorescent lighting system that goes to high voltage quickly without warming up first.

Rated Life: Half the expected lifespan of a particular kind of lamp.

Reactive Power: The voltage and current taken up by reactive loads.

Real (Active) Power: The measurment in watts or kilowatts measuring the rate at which energy is transferred.

Receptacles: Power sources within a structure.

Reflector/Refractor: A light fixture’s part that redirects a light’s path.

Regulation: The ability a ballast has to uphold fluctuations in voltage.

Relay: A device used to turn a load on or off during electrical current changes.

Resistor: Any limitation on a current’s flow.

Retrofit: Upgrading a feature based on previous installations.


Sconce: Lighting fixtures that attached to the wall.

Semi-spectacular: Characteristics of a material that creates light reflection.

Service: Materials used to deliver electric energy from a utility into a wiring system.

Series Gap: Areas in the internal system in which voltage is suppose to appear.

Series/Multiple: Two coils wound together to create a series of operating systems.

Service Cable: Cables used to transfer conductors.

Spacing Criterion: The maximum spacing requirement for interior lighting systems for appropriate light.

Specular: A surface that is polished or mirror.

Starter: A device that is used to start a fluorescent lamp.

Stroboscopic Effect: An effect that is created when machinery is rotating, but appears to be standing still.

Switchboard: An assembly of panels that are mounted with protective devices.

Switches: A interruption to a circuit that controls the flow of electricity.

Symmetric: The natural flow of a electrical current.

Systems Capacity: The maximum allowance of electricity allowed for one system.


Tap: Connections made from an outside wiring system.

Tandem Wiring: A ballast shared by two or more luminaries for heightened efficiency.

Task Lighting: Lighting that is installed in particular areas where tasks are performed.

Three-Way Switch: A switch allowing two switches to control a single lighting system.

Track and Accent Lighting: Lighting used to highlight certain areas or walls in residential homes and businesses.

Transfer Switch: A device that can connect to different sources.

Transformer: A device that lets electromagnetic energy transfer from one circuit to another.

Transient: A amplitude that is overlaid onto normal voltage.

Translucent: Any material that allows light to pass directly through with a small amount of distortion.

Transparent: Any material that allows light to pass directly through with little or no distortion.

Troffer: A recessed light fixture that is built in the ceiling.

Turn Ratio: The turn count of a high voltage winding vs. low voltage winding.


UL (Underwriters Laboratories Inc.): A non-profit safety organization.

Uninterruptible Power Supply: A device that constantly puts out a current, even with interruption.

Uplight: Light that is directed at or about 90 degress.

UV Radiation: Invisible light rays


Vandal-resistant: Fixtures that resist breaking or tampering

Vapor-Tight Luminaire: A lighting fixture that is protected against water vapor and gas

VCP (Visual Comfort Probability): A system used to rate the output of direct glare.

Very High Output (VHO): A fluorescent lamp that operates at a high current and thus puts off more light.

Volt: An flow of electricity that carries one ampere.

Voltage Drop: A drop in voltage due to an electrical resistance or failure.


Wall Grazing: Light and shadow effects on a surface.

Wall Washing: A lighting method that produces a constant level of light to reduce surface texture.

Watt: A unit of electricity that is equal to one ampere.

Wiring: The system of wires that distributes electricity throughout the entirety of a building.

Whole-House Fan: A fan that runs ventilation for an entire building.