What is the minimum size wire that can be used for a 9kW range?

What is the minimum size wire that can be used for a 9kW range?

• A. No. 10 copper
• B. No. 8 copper
• C. No. 6 copper
• D. No. 12 copper

Answer: (B)

To determine the minimum size wire that can be used for a 9kW range, it is essential to calculate the necessary amperage using the formula:

Amperage (A) = Power (W) / Voltage (V).

Assuming the range operates at 240 volts, the calculation would be:

Amperage = 9000 W / 240 V = 37.5 A.

According to the National Electrical Code (NEC) guidelines, the wire must not only handle the calculated load but also provide a safety factor, especially for continuous loads which should not exceed 80% of the circuit rating. Therefore, for a system operating at 37.5 A, you would typically need a wire gauge that can handle a larger rating.

No. 8 copper wire has an ampacity of 40 A, which is suitable for a load that requires up to 37.5 A, thereby allowing for safe operation within the limits of the wire’s capacity. It also provides an adequate safety margin for potential overloads.

In contrast, smaller gauges such as No. 10 or No. 12 copper would not provide sufficient ampacity for this application. No. 10 typically supports up to 30 A, and