Electrical Definitions


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Electrical Definitions

Letter - L


Equipment or materials to which has been attached a label, symbol, or other identifying mark of an organization that is acceptable to the authority having jurisdiction and concerned with product evaluation, that maintains periodic inspection of production of labeled equipment or materials, and by whose labeling the manufacturer indicates compliance with appropriate standards or performance in a specified manner.


Lagging Load

An inductive load with current lagging voltage. Since inductors tend to resist changes in current, the current flow through an inductive circuit will lag behind the voltage. The number of electrical degrees between voltage and current is known as the "phase angle". The cosine of this angle is equal to the power factor (linear loads only).


Lead and Lag

(See "Phase Difference")


Lighting Outlet

An outlet intended for the direct connection of a lampholder, a luminaire (lighting fixture), or a pendant cord terminating in a lampholder.


Line Conditioner

This term isn't used consistently, therefore its meaning has been blurred. The term is sometimes used to describe equipment that provides some type of filtering or Regulation to an AC power source and may be any of the following devices: Surge Suppressor, Ferroresonant Transformer, AC Filter or Tap Changing Regulator.


Line Imbalance

Unequal loads on the phase lines of a multiphase feeder.


Linear Load

A load in which the current relationship to voltage is constant based on a relatively constant load impedance.



Equipment, materials, or services included in a list published by an organization that is acceptable to the authority having jurisdiction and concerned with evaluation of products or services, that maintains periodic inspection of production of listed equipment or materials or periodic evaluation of services, and whose listing states that the equipment, material, or services either meets appropriate designated standards or has been tested and found suitable for a specified purpose.


Live Parts

Energized conductive components.



The amount of power used.


Load Balancing

Switching the various loads on a multi-phase feeder to equalize the current in each line.


Location, Damp

Locations protected from weather and not subject to saturation with water or other liquids but subject to moderate degrees of moisture. Examples of such locations include partially protected locations under canopies, marquees, roofed open porches, and like locations, and interior locations subject to moderate degrees of moisture, such as some basements, some barns, and some cold-storage warehouses.


Location, Dry

A location not normally subject to dampness or wetness. A location classified as dry may be temporarily subject to dampness or wetness, as in the case of a building under construction.


Location, Wet

Installations under ground or in concrete slabs or masonry in direct contact with the earth; in locations subject to saturation with water or other liquids, such as vehicle washing areas; and in unprotected locations exposed to weather.



A complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and ballast (where applicable), and to connect the lamps to the power supply.