Shielded cable is a special cable with a mesh braided outer layer. Cable shielding means the outer layer is grounded at one end, allowing external electromagnetic and magnetic field radiation to pass directly into the ground without interfering with the inner wires.
More sophisticated shielded cables have two shielding layers: the mesh braided wire protects against magnetic field radiation, and the aluminum foil protects against electromagnetic radiation.
Shielded cable is commonly used for cable TV coaxial cables, inverter-to-motor leads, and power supplies and analog leads in areas subject to interference.
Shielded cable is designed to resist interference and prevent external electromagnetic fields from entering the line. It is generally used for high-frequency, low-level signal lines. The most common example is cable TV coaxial cable. In addition to the inner conductor, a metal mesh shields the outer conductor, which also serves as a signal return path. In communications cables, in addition to the copper core, the core is wrapped in aluminum foil and grounded to provide a shield.
The shield must be grounded to ensure effective shielding. When high-frequency electromagnetic fields pass through the shield, they generate eddy currents and are lost.
