Glossary

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There are 36 names in this directory beginning with the letter D.
Damp Location
An outdoor location that is partially protected from weather or an indoor location subject to a moderate degree of moisture, such as a basement.

dB Loss
The loss of a signal in a conductor expressed in decibels.

DC
Direct Current.

Decibel (db)
A unit to express differences of power level. Used to express power gain in amplifiers or power loss in passive circuits or cables.

Dedicated Circuit
In a residence, a 120, 120/240, or 240 volt circuit that is installed to supply power to specific equipment indoors or outdoors, such as a large appliance or heating and air conditioning equipment.

Degree Rise
The amount of increase in temperature caused by the introduction of electricity into a unit.

Delay Line
A cable made to provide very low velocity of propagation with long electrical delay for transmitted signals.

Denier
A term borrowed from the textile industry for sizing yarns. Denier is defined as the weight in grams of 9,000 yards of yarn.

Derating Factor
A factor used to reduce the current-carrying capacity of a wire when used in environments other than that for which the value was established.

Design Voltage
Voltage for which a cable is designed.

Dessicant
Water or moisture absorbent material used to prevent moisture from damaging packaged equipment or other merchandise.

Die
A device used in the drawing of a wire; the element through which the wire is drawn, to achieve a predetermined diameter. A mold used to form a plastic compound around a wire or cable.

Dielectric
An insulating medium which intervenes between two conductors and permits electrostatic attraction and repulsion to take place across it.

Dielectric Breakdown
The voltage required to cause an electrical failure or breakthrough of the insulation.

Dielectric Constant (K)
The ratio of the capacitance of a condenser with dielectric between the electrodes to the capacitance when air is between the electrodes. Also called Permittivity and Specific Inductive Capacity.

Dielectric Loss
The power dissipated in a dielectric as the result of the friction produced by molecular motion when an alternating electric field is applied.

Dielectric Strength
The voltage which an insulating material can withstand before breakdown occurs, usually expressed as a voltage gradient (such as volts per mil).

Dielectric Test
A test in which a voltage higher than the rated voltage is applied for a specified time to determine the adequacy of the insulation under normal conditions.

Digital
Transmission data representative by discrete characters.

Direct Burial Cable
A cable installed directly in the earth.

Direct Current (DC)
An electric current which flows in only one direction.

Direct Current Resistance (DCR)
The resistance offered by any circuit to the flow of direct current.

Direction of Lay
The lateral direction in which the strands of a conductor run over the top of the cable conductor as they recede from an observer looking along the axis of the conductor or cable. Also applies to twisted cable.

Discrete Wiring
Wire or wires having distinct identity and purpose.

Disruptive Discharge
A sudden, large increase in current through an insulation medium due to the complete failure of the medium under the electrostatic stress.

Double Shield
Two shields, on over the other, used to improve the shield effectiveness.

Drain Wires
A number of small gauge bare wires applied concentrically about the insulation shield of a high voltage cable for the purpose of a fault current return path.

Draw Feed Stock
Rod or wire that is subsequently drawn to a smaller size.

Drawing
In the manufacture of wire, pulling the metal through a die or series of dies for reduction of diameter to a specified size.

Dry Location
A location not normally subject to dampness or wetness.

Duct
An underground or overhead tube for carrying electrical conductors.

Duplex
Two-way data transmission on a four-wire transmission line.

Duplex Cable
A cable composed of two insulated single-conductor cables twisted together.

Duplex Parallel
Typically used in the thermocouple industry to denote two parallel conductors of dissimilar metals insulated in parallel without twists and jackets. Commonly applied to thermocouple grades and extension wires.

Durometer
A measuring device used to denote the hardness of plastic. For most flexible plastics, the A or D scale is used.

Duty Rating
A rating that describes the ability of an electric device to carry a current load for a given frequency of use.