When is a “screened”cable rather than a “shielded” one chosen?
Screening is used to reduce possible electromagnetic interference due to the passage of electricity through the conductor when the cable is situated in the proximity of electronic circuits. In fact, the voltage generates an electromagnetic field during its passage, which may interfere with electronic equipment. The presence of the screen permits the reduction of this type of phenomenon; in fact, when the electromagnetic waves propagate from the conductor towards the surrounding area, they encounter the screening they are directed to by the current, which is the result of the electric power originated by the waves themselves. Thus, the electromagnetic effect is depleted by a barrier of copper sheathing. Shielding is obtained with a sheath of steel and has got the sole purpose of protecting the silicone cable (which is rather fragile) from potential heavy contact that could compromise the integrity and functional efficiency of the cable.
