Electrical Glossary: A Detailed Glossary of All Electrical Terms

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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

[U]

 

 

Uninterruptible Power Supply:

A device that provides a constant regulated voltage output in spite of interruptions of the normal power supply. It includes filtering circuits and is usually used to feed computers or related equipment which would otherwise shutdown on brief power interruptions. Abbreviated UPS.

 

 

 

Universal Taps:

A combination of six primary voltage taps consisting of four 2-1/2% FCBN and two 2-1/2: FCAN, covering 15% voltage range.

 

[V]

 

 

Vapor Barrier:

Also called a vapor retarder, this is a material that retards the movement of water vapor through a building element (such as walls, floors, and ceilings) and prevents metals from corroding and insulation and structural wood from becoming damp.

 

 

 

Ventilated:

Provided with a means to permit circulation of air sufficient to remove an excess of heat, fumes, or vapors.

 

 

 

Volt:

The electrical potential difference or pressure across a one ohm resistance carrying a current of one ampere. Named after Italian physicist Count Alessandro Volta 1745-1827.

 

 

 

Volt Ampere:

A unit of apparent power equal to the mathematical product of a circuit voltage and amperes. Here, apparent power is in contrast to real power. On ac systems the voltage and current will not be in phase if reactive power is being transmitted. Usually abbreviated VA.

 

[W]

 

 

Watertight:

Constructed so that moisture will not enter the enclosure under specified test conditions.

 

 

 

Waterproof:

Constructed or protected so that exposure to the weather will not interfere with successful operation.

 

 

 

Watt:

A unit of power equal to the rate of work represented by a current of one ampere under a pressure of one volt. Named after the Scottish engineer James Watt, 1819.

 

 

 

Wiring:

A distribution network of wire that conducts electricity to receptacles, switches and appliances throughout a building/home to provide electricity where needed.

 

 

 

Whole-House Fan:

A large fan used to ventilate your entire house. This is usually located in the highest ceiling in the house, and vents to the attic or the outside. Although whole-house fans are a good way to draw hot air from the house, you must be careful to cover and insulate them during the winter, when they often continue to draw hot air from people's houses.