In shielded cable, which wire is intentionally tied to ground to drain static or noise from the foil shield?

In shielded cable, which wire is intentionally tied to ground to drain static or noise from the foil shield?

• A. Ground conductor
• B. Shield wire
• C. Drain wires
• D. Bonding strap

Answer: (C)

Shielded cable uses a foil or braided shield to block interference, and a drain wire provides a direct path to ground for charges that accumulate on that shield. By bonding the drain wire to the shield and then grounding it, static electricity and RF noise collected by the shield are carried away to earth, keeping the signal conductors from picking up interference. The drain wire is the specific element designed for this purpose, whereas a general ground conductor serves broader fault-grounding, the shield wire is not the dedicated drain path, and a bonding strap is used for bonding metal parts, not for draining noise from the shield.

Shielded cable uses a foil or braided shield to block interference, and a drain wire provides a direct path to ground for charges that accumulate on that shield. By bonding the drain wire to the shield and then grounding it, static electricity and RF noise collected by the shield are carried away to earth, keeping the signal conductors from picking up interference. The drain wire is the specific element designed for this purpose, whereas a general ground conductor serves broader fault-grounding, the shield wire is not the dedicated drain path, and a bonding strap is used for bonding metal parts, not for draining noise from the shield.