What would be the minimum size branch circuit if the calculated ampacity is 20.45 A?

To determine the minimum size branch circuit required when the calculated ampacity is 20.45 A, you need to round up to the nearest standard breaker size that can safely accommodate the load. In electrical standards, circuit breakers come in standard sizes, which include 15 A, 20 A, 25 A, and 30 A.

Given that the calculated ampacity is 20.45 A, the circuit needs to be sized to handle this load without exceeding its capacity. The next standard size after 20.45 A is 25 A. However, since the question asks for the minimum size branch circuit, a 20 A circuit is adequate here because it can safely manage a load of up to 20 A.

Choosing a branch circuit size that is less than the calculated ampacity would not provide a safe operating condition, as it risks overheating and potentially causing a failure. Therefore, recognizing that 20 A is sufficient to handle the load of 20.45 A, confirms that it is indeed the appropriate answer.

Understanding this concept of rounding up in electrical calculations ensures safe and reliable circuit design.