Definition
An electrical wire enclosed in a grounded metallic sheath or braid that surrounds the insulated conductor. The shield blocks external electromagnetic interference from entering the wire and prevents signals carried inside the wire from radiating outward.
Plain English
A wire wrapped in a thin metal mesh or foil that acts as a barrier. The barrier stops outside electrical noise from getting in and stops the wire's own signal from leaking out.
Context Anchor
Seen in aircraft electrical wiring, especially around radios, audio wiring, ignition-related wiring, and sensitive instrument circuits.
Derivation
Shield comes from Old English 'scield', meaning a protective cover used in battle. The metal braid 'shields' the inner wire from electrical attack — stray signals and interference — much like a physical shield blocks blows.
Why Pilots Care
Prevents radio static, navigation errors, and erratic instrument readings caused by electromagnetic interference from other aircraft systems.
Intuition Check
Shielded does not mainly mean protected from rubbing, heat, or physical damage. Here, the shield is an electrical screen that helps block interference.
Example Sentence 1
The magneto P-leads are run as shielded conductors to prevent ignition noise from disrupting the radios.
Example Sentence 2
During the annual inspection the avionics technician checked all shielded conductors for proper grounding at the connector ends.