Magnetic wire or enameled wire is a copper wire or aluminum wire coated with a very thin insulating layer, that is, enameled aluminum wire or copper-clad aluminum wire. It is used in the construction of transformers, inductors, motors, generators, speakers, hard disk head actuators, electromagnets, electric guitar pickups, and other applications that require tightly insulated coils.

The wire itself is usually electrolytically refined copper that has been fully annealed. Aluminum magnet wire is sometimes used in large transformers and motors. Insulating materials are usually made of tough polymer film materials instead of glass enamel, as the name suggests.

The most suitable materials for magnet wire applications are non-alloy pure metals, especially copper. Taking into account factors such as chemical, physical, and mechanical performance requirements, copper is considered the preferred conductor of magnet wire.

Generally, the magnet wire is composed of electrolytically refined copper that is fully annealed to allow tighter winding when making the magnet coil. High-purity oxygen-free copper grades are used for high-temperature applications in reducing atmospheres or hydrogen-cooled motors or generators.

Sometimes for economic reasons, aluminum magnet wire is sometimes used as a substitute for large transformers and motors. Due to the low conductivity of aluminum wire, its cross-sectional area is 1.6 times larger than that of Copper Clad Aluminum Wire to achieve comparable DC resistance.