Skin effect electric heat tracing is also called skin effect electric heat tracing. Because when an alternating current flows through the wire, eddy currents will be generated inside the wire according to Lenz's law, which is opposite to the direction of the current in the center of the wire. Since the center of the wire is larger than the magnetic flux on the surface of the wire, the electromotive force generated at the center of the wire is larger than the electromotive force generated near the surface of the wire. As a result of this action, the current flows on the surface and there is no current in the center. This magnetic field caused by the current of the wire itself causes the wire current to flow on the surface. Near the non-energized ferromagnetic material, a magnetic field in the opposite direction is generated on the surface of the non-energized ferromagnetic material. With the magnetic field, a current that cuts the magnetic field lines is generated. This current is called the eddy current.