When selecting a breaker (circuit breaker) for the primary side of a transformer, there are three points to consider.
　1: The breaker must not operate at the normal (rated) operating current.
　2: The breaker must be able to shut down the transformer in the event of a short circuit accident.
　3: The breaker must not trip due to transformer excitation inrush current.

For details, please refer to the video.

2023.5.12：FAQ What are the 3 key points in transformer primary-side breaker selection?