Magnet_wire, enameled wire, enameled wire or winding wire or insulated wire, is a bare copper wire or aluminum wire coated with a very thin layer of insulation or covered with paper or fiberglass or insulation films. What is magnet wire used for? Magnet wire is widely used in transformer, motor, welding machine,refrigeration compressor, solar power, electrical equipment, household, appliances, medical equipment and transportation, etc, which require tight coils of wire.