Blue Sea Systems AMI/MIDI Safety Fuse Block

The Blue Sea Systems AMI/MIDI Safety Fuse Block is a sealed, ignition-protected single-circuit block for high-amperage AMI (Bussmann) or MIDI (Littelfuse) fuses. Its IP66-rated cover shields the fuse from spray, rain, and washdowns while meeting ABYC/USCG insulation requirements.

Key features

• 200A maximum with 4/0 AWG cable, 32V DC maximum
• Ignition protected for gasoline or diesel powered boats: SAE J1171, ISO 8846
• IP66 sealed cover protects fuses from the marine environment
• Cover breakouts allow wire access in any direction
• Accepts Blue Sea's Square Format standard or custom label

This block accepts AMI or MIDI fuses in the 30-200A range (sold separately), and is the sealed, ignition-protected counterpart to Blue Sea's open MAXI and ANL blocks — reach for it where the installation is exposed to spray or needs ignition-protection documentation.

Torque the terminal stud to 120 in-lb and the fuse screw to 27 in-lb. Because the cover is fully sealed, confirm the fuse is seated correctly before closing it — reopening in a wet cockpit is more of a hassle than with an open block.

This block is a common choice for windlass, bow thruster, or inverter feeds mounted in an exposed helm, flybridge, or anchor locker location where an open MAXI or ANL block would be more vulnerable to spray. Because it accepts both AMI and MIDI fuses interchangeably, confirm which family your fuse supplier stocks before ordering spares, since the two aren't physically interchangeable with other fuse families despite sharing this block. Keep a small stock of both AMI and MIDI fuses on hand if your supply chain sometimes substitutes one for the other, since either family works in this same block.