Shielded cables include an additional conductive layer—either foil (FTP), braid (STP), or both (S/FTP)—wrapped around the twisted pairs. This layer serves as a barrier against external noise like EMI and RFI, common in high-voltage, industrial, and medical environments. This is where shielded cables come in. Unlike standard unshielded cables, shielded cables are specifically designed to block unwanted electrical noise and prevent signal distortion. They play a vital role in electromagnetic compatibility (EMC)—ensuring that electronic systems can operate reliably. This guide explains how shielded and unshielded cables work, where they should (and shouldn't) be used, and what hidden variables procurement teams often miss when sourcing them. This. In principle, any electrical cable can cause or suffer electronic magnetic interference due to the coupling effect.
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