Direction of Lay: Defined as “right-hand” or “Left-hand” these terms have the same meaning as specified for screw threads.  It is said to be “right-handed” if, when assembled with a fixed mating thread and twisted in a clockwise direction, it moves away from the operator; and “left-handed” if, when assembled with a fixed mating thread and twisted in a clockwise direction, it approaches the operator.  The right-hand lay is also know as Z-lay and left hand lay as S-Lay.

Distributor: The portion of any underground cable with which a service line is, or is intended to be, immediately connected.

Dividing Box: A box fitted to one end of a two, three, four core or multicore cable for termination.

Dielectric : A material with good electric insulating characteristics, insulating medium.

Dielectric Constant : A term used to define the degree of insulating characteristics possessed by a dielectric.

Typical Values of Dielectric Constant

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.

Drawing : The process of reducing a cylindrical rod or wire to a desired diameter by pulling the wire through a die or series of dies thus stretching the wire.