Understand Electric Terms

Below is list of electrical terms. Waverly Light and Power is committed to educating residents about electricity.

• Absolute Humidity - The ratio of the mass of water vapor to the volume occupied by a mixture of water vapor and dry air.
• Active Power - The power (in Watts) used by a device to produce useful work. Also called input power.
• AMPS - Amps are the amount of electricity or current flowing through a wire, similar to the flow of water through a pipe. A typical residential heating service capacity is 100 amps. 200 amps or more are required for electric heating.
• Air Conditioner - A device for conditioning air in an interior space. A Room Air Conditioner is a unit designed for installation in the wall or window of a room to deliver conditioned air without ducts. A Unitary Air Conditioner is composed of one or more assemblies that usually include an evaporator or cooling coil, a compressor and condenser combination, and possibly a heating apparatus. A Central Air Conditioner is designed to provide conditioned air from a central unit to a whole house with fans and ducts.
• Air Conditioning - The control of the quality, quantity, and temperature-humidity of the air in an interior space.
• Air Space - The area between the layers of glazing (panes) of a window.
• Array (Solar) - Any number of solar photovoltaic modules or solar thermal collectors or reflectors connected together to provide electrical or thermal energy.
• Attic Fan - A fan mounted on an attic wall used to exhaust warm attic air to the outside.
• Attic Vent - A passive or mechanical device used to ventilate an attic space, primarily to reduce heat buildup and moisture condensation.
• Audit (Energy) - The process of determining energy consumption, by various techniques, of a building or facility.
• Circuit Breaker - An automatically-operated electrical switch designed to protect an electrical circuit from damage caused by overload or short circuit. Its basic function is to detect a fault condition and, by interrupting continuity, to immediately discontinue electrical flow.
• Fuel - Any material that can be burned to make energy.
• Furnace (Residential) - A combustion heating appliance in which heat is captured from the burning of a fuel for distribution, comprised mainly of a combustion chamber and heat exchanger.
• Fuse - A safety device consisting of a short length of relatively fine wire, mounted in a holder or contained in a cartridge and connected as part of an electrical circuit. If the circuit source current exceeds a predetermined value, the fuse wire melts (i.e. the fuse 'blows') breaking the circuit and preventing damage to the circuit protected by the fuse.
• Gasket/Seal - A seal used to prevent the leakage of fluids, and also maintain the pressure in an enclosure.
• Generator - A device for converting mechanical energy to electrical energy.
• Geothermal Energy - Energy produced by the internal heat of the earth; geothermal heat sources include: hydrothermal convective systems; pressurized water reservoirs; hot dry rocks; manual gradients; and magma. Geothermal energy can be used directly for heating or to produce electric power.
• Greenhouse Gases - Those gases, such as water vapor, carbon dioxide, tropospheric ozone, methane, and low level ozone that are transparent to solar radiation, but opaque to long wave radiation, and which contribute to the greenhouse effect. 
• Grid-Connected System - Independent power systems that are connected to an electricity transmission and distribution system (referred to as the electricity grid) such that the systems can draw on the grid's reserve capacity in times of need, and feed electricity back into the grid during times of excess production.
• Heat - A form of thermal energy resulting from combustion, chemical reaction, friction, or movement of electricity. As a thermodynamic condition, heat, at a constant pressure, is equal to internal or intrinsic energy plus pressure times volume.
• Joist - A structural, load-carrying building member with an open web system that supports floors and roofs utilizing wood or specific steels and is designed as a simple span member.
• Kneewall - A wall usually about 3 to 4 feet high located that is placed in the attic of a home, anchored with plates between the attic floor joists and the roof joist. Sheathing can be attached to these walls to enclose an attic space.
• Load Leveling - The deferment of certain loads to limit electrical power demand, or the production of energy during off-peak periods for storage and use during peak demand periods.
• Loose Fill Insulation - Insulation made from rockwool fibers, fiberglass, cellulose fiber, vermiculite or perlite minerals, and composed of loose fibers or granules can be applied by pouring directly from the bag or with a blower.
• Mean Power Output (of a Wind Turbine) - The average power output of a wind energy conversion system at a given mean wind speed based on a Raleigh frequency distribution.
• Mean Wind Speed - The arithmetic wind speed over a specified time period and height above the ground (the majority of U.S. National Weather Service anemometers are at 20 feet (6.1 meters).
• Natural Gas - A hydrocarbon gas obtained from underground sources, often in association with petroleum and coal deposits. It generally contains a high percentage of methane, varying amounts of ethane, and inert gases; used as a heating fuel.
• Nuclear Energy - Energy that comes from splitting atoms of radioactive materials, such as uranium, and which produces radioactive wastes.
• Panel (Solar) - A term generally applied to individual solar collectors, and typically to solar photovoltaic collectors or modules.
• Peak Demand/Load - The maximum energy demand or load in a specified time period.
• Phase - Alternating current is carried by conductors and a ground to residential, commercial, or industrial consumers. The waveform of the phase power appears as a single continuous sine wave at the system frequency whose amplitude is the rated voltage of the power.
• Phase Change - The process of changing from one physical state (solid, liquid, or gas) to another, with a necessary or coincidental input or release of energy.
• Photovoltaic (Conversion) Efficiency - The ratio of the electric power produced by a photovoltaic device to the power of the sunlight incident on the device.
• Photovoltaic (PV; Solar) Array - A group of solar photovoltaic modules connected together. 
• Power - Energy that is capable or available for doing work; the time rate at which work is performed, measured in horsepower, Watts, or Btu per hour. Electric power is the product of electric current and electromotive force.
• Power Transmission Line - An electrical conductor/cable that carries electricity from a generator to other locations for distribution.
• Radiant Barrier - A thin, reflective foil sheet that exhibits low radiant energy transmission and under certain conditions can block radiant heat transfer; installed in attics to reduce heat flow through a roof assembly into the living space.
• Radiant Heating System - A heating system where heat is supplied (radiated) into a room by means of heated surfaces, such as electric resistance elements, hot water (hydronic) radiators, etc.
• Steam - Water in vapor form; used as the working fluid in steam turbines and heating systems.
• Thermal Energy - The energy developed through the use of heat energy.
• Transformer - An electromagnetic device that changes the voltage of alternating current electricity. It consists of an induction coil having a primary and secondary winding and a closed iron core.
• Transmission - The process of sending or moving electricity from one point to another; usually defines that part of an electric power provider's electric power lines from the power plant buss to the last transformer before the customer's connection.
• Transmission and Distribution Losses - The losses that result from inherent resistance in electrical conductors and transformation inefficiencies in distribution transformers in a transmission and distribution network.
• Transmission Lines - Transmit high-voltage electricity from the transformer to the electric distribution system.
• Voltage - The amount of electromotive force, measured in volts, that exists between two points.