shielding

What is Shielding?

Metallic material added to cabling to reduce susceptibility to noise due to electromagnetic interference (EMI). Shielding usually takes one of two forms:

• A braided copper or aluminum mesh enclosing the signal-carrying wires. This type of shielding offers superior performance and should be used in industrial areas where heavy machinery generates a lot of EMI.
• An aluminum foil sleeve that encloses individual wires or the entire wire bundle. This kind of shielding is more suitable for office environments to shield against noise due to air conditioners, fans, and other motors.

For best performance, you can combine both kinds of shielding. An additional uninsulated drain wire is sometimes used to terminate the shield; it runs the length of the wire in contact with the foil sleeve or mesh. Shielded cabling is generally more expensive than unshielded cabling.

See also:

• coaxial cabling
• shielded twisted-pair (STP) cabling