ZCASE® Single MEGA / Starter Fuses Littelfuse ZCASE® Single MEGA / Starter Fuses are bolt-down automotive fuses with a wide rating range up to 600A. The Time Current characteristic of these fuses is similar to the MEGA design and can be used as full-wire protection up to 250A. Higher ratings are typically used for starter fuse applications as a protector fuse. Littelfuse ZCASE Single MEGA High-Current Fuses are optimized for a one-bolt connection M6 (40A to 250A) or M8 (300A to 600A) and can used directly on a battery-post or busbar connection.