The range is given for the choice of power circuit-breaker to be used for different models. During the safety tests, Delta follows the recommended value advised by safety agencies i.e. 16A min. This is because during safety failure tests, we depend on the power supply fuse to blow rather than the power circuit-breaker to open. But if a lower value power circuit-breaker is used, the power circuit-breaker will trip before the fuse is open thus avoiding the field returns. Therefore we do not recommend using the fuse instead of the power circuit-breaker as the backup.