The wrapped wire is made of natural silk, polyester fiber, glass fiber, insulating paper or synthetic resin film, etc., tightly wrapped on the conductive wire core to form an insulating layer. There are also insulating layers wrapped around the enameled wire. In addition to thin-film insulation, others such as glass filaments need to be dipped in adhesive insulating varnish to improve their electrical, mechanical and moisture-proof properties. In fact, they are combined insulation.