The fixture should have no iron parts to form a closed magnetic circuit. This is because when the cable core passes current, a magnetic field line is generated around it. The magnetic field line is proportional to the current passing through the wire core. If magnetic conductive materials such as iron parts are used, according to the It can be known from electromagnetic induction that eddy currents will be generated in the iron parts to make the cable heat up and even burn out the cable. Therefore, it is not possible to use iron parts as a fixing fixture for single-core AC cables.