What factor determines the plating type used on a copper conductor?

• A. Insulation color
• B. Wire gauge
• C. Length of run
• D. Highest expected temperature the conductor will get

Answer: (D)

The factor being tested is the highest temperature the conductor will reach. Plating is chosen to withstand operating and soldering temperatures without degrading, so the material must remain intact and maintain good conductivity and corrosion resistance at that temperature. If the conductor is expected to run hot, some plating layers can diffuse into copper, soften, or oxidize more quickly, compromising the connection. That’s why temperature limits drive the plating choice: it ensures reliability in the actual service environment. Insulation color and the physical size or length of the wire don’t determine which plating is used—the temperature and related operating conditions do.