Conductors are solid or stranded soft copper. Stranded conductors are concentrically stranded. The insulation is a high molecular weight polyethylene (HMWPE). Typically, this insulation is a thick 0.110″ (110 mils) coating.
Used as uninsulated transformer risers at voltages of up to 35kV.
Although not treated as an insulation, the covering on transformer riser wire does reduce faults due to atmospheric conditions, shorts caused by excessive vibrations, and faulting caused by objects crossing the leads.