Insulated wire

Insulated wire is a copper conductor wrapped in a skin of plastic. The copper carries the current, and the plastic keeps it from touching other wires, metal parts or people. It is the basic ingredient of every cable.

The conductor is copper wire. For wires that must bend, many fine strands are twisted together, which makes the wire far more flexible than one thick strand; they are sometimes tin plated to resist corrosion. The bundle is fed through the center of an extruder, where molten PVC is pressed through a die around the moving copper, coating it evenly as it passes. The wire then runs through a long trough of water to cool. Pigment in the plastic sets its color, so wires can be told apart. The finished wire is checked for weak spots, often with a high-voltage tester, printed with its ratings and wound on reels.

In the TV, insulated wires run inside the power cord and are bundled into each wiring harness between the boards. The thickness of the copper sets how much current a wire can carry, and the insulation sets how much voltage it can withstand.