Electrical Definitions


 Copyright - Durand & Associates  

Electrical Definitions

Letter - D

Dead Front

Without live parts exposed to a person on the operating side of the equipment. 


Demand Factor

The ratio of the maximum demand of a system, or part of a system, to the total connected load of a system or the part of the system under consideration.



A unit of an electrical system that is intended to carry but not utilize electric energy.



The insulating material between the plates of a capacitor.



Any two-electrode device that conducts in only one direction.


Direct Current

A current is a continuous flow of electric current from positive to negative poles.


Disconnecting Means

A device, or group of devices, or other means by which the conductors of a circuit can be disconnected from their source of supply. 


Diversity Factor

The ratio of the sum of the maximum power demands of the subdivisions, or parts of a system, to the maxi-mum demand of the whole system or of part of the system under consideration.


Dry Location

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.



Constructed or protected so that dust will not interfere with its successful operation.



Constructed so that dust will not enter the enclosing case under specified test conditions.



Dwelling Unit. One or more rooms for the use of one or more persons as a housekeeping unit with space for eating, living, and sleeping, and permanent provisions for cooking and sanitation.

Dwelling, One-Family. A building that consists solely of one dwelling unit. 

Dwelling, Two-Family. A building that consists solely of two dwelling units. 

Dwelling, Multifamily. A building that contains three or more dwelling units. 



A converter with both motor and generator in one magnetic field, either with two armatures, or with one armature having two separate windings.