ArabianExperts. Arabian Experts.The two primary disconnect switch designs are fusible and non-fusible. As the name implies fusible disconnect switches utilize fuses to protect against overcurrent and short circuiting. In contrast non-fusible disconnect switches do not protect against short circuiting and simply switch the electrical flow on or off. Non-fusible disconnect switches are only advised on systems with fault currents of less than 5kA or a dedicated fuse upstream of the safety switch.