A shielded cable is an electrical cable of one or more insulated conductors enclosed by a common conductive layer.
Foil screens require a drain wire in order to terminate them into a connector. Drain wires will normally be the same size as the other cores in the cable, and are normally placed in the interstices of the other cores. Drain wires are not always necessary if the foil is paired up with a braid. Foil screens offer 100 % coverage which is more effective at higher frequencies.
Braided screens of Tin Plated Copper (TPC) wires and Aluminium/Polyester (Al/Pr) foils provide protection from electrical interference either from other sources within the cable (such as power and data cores in the same cable) or from external sources. Braided screens offer a large amount of copper which is beneficial at lower frequencies.
This is the process whereby multiple braided screens and a my-metal foil screen are used in conjunction with one another to provide complete protection. A combination of both foil and braid will provide the best screening over a wide range of frequencies. However, this combination of screen does significantly limit cable flexibility.
There are three commonly used methods of mechanical protection. Stainless steel wire braids are offered by Habia Cable in preference to heavy galvanised steel as these offer significant crush and cut-through resistance without the bulk of a galvanised steel wire armour. Aramid braids can also be used where the cable must remain flexible. Aramid also offers significant cut-through resistance, along with excellent tensile strength.