Can a time delay fuse be used to replace a fast acting fuse?

Fast-acting fuses are generally used to protect sensitive components from damage so replacing fast-acting fuses with a time-delay fuse could result in damage to your equipment. NEC guidelines are also different for applying fast-acting and time delay fuses. Fuse sizing may vary. It is best to thoroughly understand the circuit before making a decision to switch from a fast-acting fuse to one with time delay.