33.3    Material

A.    Conductors

(1)    General: Conductors shall be of copper, aluminum, or other metal of suitable electrical and mechanical properties.

(2)    Size: Conductors shall be of sufficient size to carry the estimated maximum load current without serious deterioration of the insulation.

B.    Insulations

(1)    Voltage Rating: Insulation applied over the conductor shall be of a voltage rating adequate to withstand the operating voltage and be suitable for the operating conditions.

(2)    Materials: Insulation materials may be, but are not limited to, oil impregnated paper, rubber, plastics and varnished cambric.

(3)    Splices and Joints: Insulation applied in the field, such as for splices and joints, shall provide electrical properties equivalent to the insulation of the cables being joined.

C.    Shielding

(1)    General: Shielding or equivalent shall be considered for non–metallic covered cables operating at a circuit voltage over 2,000 volts, and shall be required for all cables operating at 5,000 volts or more, except that shielding shall not be required for series street lighting circuits operating at less than 7,500 volts.

(2)    Materials: Shielding may consist of, but is not limited to, metallic tape, braid, wire and sheaths, or combinations of wires and conducting sheaths.  

(3)    Fault Current: Shielding and the associated ground system shall be capable of carrying fault currents which may be imposed on it by the associated system.

(4)    Jacket: Where desirable, a nonmetallic jacket may be installed over the cable shielding.