What is the rating of a cable containing 4 to 6 wires?

• A. 100% of the normal rating
• B. 80% of the normal rating
• C. 60% of the normal rating
• D. 50% of the normal rating

Answer: (B)

The rating of a cable containing 4 to 6 wires is typically set at 80% of its normal rating. This adjustment accounts for the fact that multiple wires in a cable can lead to increased heat generation due to the reduced space for heat dissipation. By reducing the operating capacity to 80%, it ensures that the cable can operate safely without overheating, which can compromise insulation and overall performance. This derating factor aligns with standards established in electrical codes to promote safety and reliability in electrical installations. Understanding these ratings is essential for choosing the appropriate cable size for any specific application, especially when multiple conductors are involved.