Non-time-delay fuses can generally be sized at what percentage of the motor full-load current?

Non-time-delay fuses are designed to provide immediate protection against short circuits and overloads, but they do not allow for momentary inrush currents that motors experience during startup. Therefore, when sizing non-time-delay fuses for motors, they can typically be set at a higher percentage of the motor's full-load current to account for these inrush conditions.

Sizing non-time-delay fuses at 300% of the motor full-load current reflects the need to tolerate these brief peaks in current without nuisance tripping, ensuring that the motor can start without immediately blowing the fuse. This is especially critical in motor applications where the starting current can be significantly higher than the operating current.

Choosing a lower percentage would not provide the necessary allowance for the inrush current that occurs when the motor first starts. Thus, 300% is recognized as an effective sizing approach for non-time-delay fuses in motor circuits.