Electrical Glossary: A Detailed Glossary of All Electrical Terms

Choose a letter below to navigate to the definition you're looking for:

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

[R]

 

 

Rainproof:

Constructed, protected, or treated so as to prevent rain from interfering with the successful operation of the apparatus under specified test conditions.

 

 

 

Rating:

The rating of an arrester - either duty cycle or MCOV rating.

 

 

 

Reactive Power:

 

The mathematical product of voltage and current consumed by reactive loads. Examples of reactive loads include capacitors and inductors. These types of loads when connected to an ac voltage source will draw current, but since the current is 90^o out of phase with the applied voltage they actually consume no real power in the ideal sense.

 

 

 

Reactor:

A device for introducing inductive reactance into a circuit for motor starting, operating transformers in parallel, and controlling current.

 

 

 

Real Power:

The rate at which work is performed or that energy is transferred. Electric power is commonly measured in watts or kilowatts. The term real power is often used in place of the term power alone to differentiate from reactive power. Also called active power.

 

 

 

Receptacles:

Power sources located throughout a building to provide electricity where needed.

 

 

 

Resistor:

Any device of material that limits the flow of current when voltage is applied.

 

[S]

 

 

Service:

The conductors and equipment for delivering electric energy from the serving utility to the wiring system of the premises served.

 

 

 

Series Gap:

Internal gap(s) between spaced electrodes in series with the valve elements across which all or part of the impressed arrester terminal voltage appears.

 

 

 

Series/Multiple:

A winding of two similar coils that can be connected for series operation or multiple (parallel) operation.

 

 

 

Service Cable:

Service conductors made up in the form of a cable.

 

 

 

Smoke And Carbon Dioxide Detectors:

Wall and ceiling mounted sensors located throughout the home used to alert occupants of deadly gasses and smoke inside the home.

 

 

 

Storm Windows:

An extra pane of glass or plastic added to a window to reduce air infiltration and boost the insulation value of a window. If you are considering adding storm windows, you should compare the costs to installing new energy-efficient windows.

 

 

 

Switchboard:

A large single panel, frame, or assembly of panels on which are mounted, on the face or back, or both, switches, overcurrent and other protective devices, buses, and usually instruments. Switchboards are generally accessible from the rear as well as from the front and are not intended to be installed on cabinets.

 

 

 

Switches:

Circuit interruption devices used to control the flow of electricity to lights, appliances, and outlets.

 

 

 

Switch Limit:

A switch that is operated by some part or motion of a power-driven machine or equipment to alter the electric circuit associated with the machine or equipment.

 

 

 

Symmetric:

A term used to explain the normal, rhythmic ac flow of current (transient or dc component = ); the steady state component of any current or fault current calculation.

 

 

 

Systems Capacity:

Represents the ability of a system to meet its customers' needs, or meet the electrical demand of its customers. System capacity is provided by generators, transmission lines, distribution networks and load management.

 

[T]

 

 

Tap:

A connection brought out of the winding at some point between its extremities, usually to permit changing the voltage or current ratio.

 

 

 

Thermostat:

A low voltage electronic switching device that monitors temperatures inside the home and turns on and off the heating or cooling system in the home.

 

 

 

Track And Accent Lighting:

Condition specific lighting that meets special lighting requirements, providing variable lighting degrees of light and may distribute light in multiple directions.

 

 

 

Transfer Switch:

An electronic device that under certain conditions will disconnect from one power source and connect to another power source.

 

 

 

Transformer:

A static electrical device which by electromagnetic induction transfers electrical energy from one circuit to another circuit usually with changed values of voltage and current in the process.

 

 

 

Transient:

A high amplitude, short duration pulse superimposed on the normal voltage.

 

 

 

Turn Ratio:

The ratio of the number of turns in the high voltage winding to that in the low voltage winding.