If a conductor is undersized for 15 A over 20 m in a 28 V system, what is the most likely consequence?

If a conductor is undersized for 15 A over 20 m in a 28 V system, what is the most likely consequence?

• A. Increased voltage drop and potential overheating.
• B. The same voltage drop regardless of gauge.
• C. Lower resistance leading to safer operation.
• D. More efficiency.

Answer: (A)

When a conductor is undersized for the current, its resistance is higher than it should be over that length. In a 28 V system, the voltage actually delivered to the load is the supply minus the voltage drop across the conductor, and that drop is V_drop = I × R_total. With 15 A flowing through 20 meters of a too-small conductor, R_total is large enough that the product I × R_total becomes a sizable portion of 28 V, reducing the voltage reaching the load. At the same time, heat produced is P = I^2 × R_total, so the same high resistance causes more heating along the conductor. This combination—larger voltage drop and overheating risk—is the most likely consequence of undersizing the conductor.

When a conductor is undersized for the current, its resistance is higher than it should be over that length. In a 28 V system, the voltage actually delivered to the load is the supply minus the voltage drop across the conductor, and that drop is V_drop = I × R_total. With 15 A flowing through 20 meters of a too-small conductor, R_total is large enough that the product I × R_total becomes a sizable portion of 28 V, reducing the voltage reaching the load. At the same time, heat produced is P = I^2 × R_total, so the same high resistance causes more heating along the conductor. This combination—larger voltage drop and overheating risk—is the most likely consequence of undersizing the conductor.