Blue Sea Systems 5191 Terminal Fuse Block

Blue Sea Systems MRBF Single-Pole Terminal Fuse Block

The Blue Sea Systems 5191-BSS (Catalog SKU 5191) is a compact, high-amperage Marine Rated Battery Fuse (MRBF) terminal fuse block designed to mount directly onto a standard 3/8" (M10) battery post stud or heavy-duty busbar terminal. By providing overcurrent protection directly at the DC power source, it satisfies ABYC requirements for placement of primary circuit protection within 7 inches (178 mm) of the battery.

Engineered to accommodate single MRBF cartridge fuses from 30 to 300 A, the 5191 is ideal for high-capacity main battery feeds, inverter installations, bow thrusters, and windlasses. Constructed with an isolated tin-plated copper bus bar and stainless steel mounting hardware, it features a flexible insulating cap that shields live electrical terminals from accidental short circuits and environment-induced corrosion.

Key Features

• Direct Battery Stud Mounting: Compact footprint mounts directly to a M10 (3/8") battery post stud or battery switch terminal, eliminating extra interconnecting cables.

• High Interrupt Capacity (AIC): Meets ABYC requirements for main battery DC circuit protection when paired with MRBF fuses (10,000A AIC @ 14V DC).

• High-Conductivity Tin-Plated Copper: Ensures minimal voltage drop and resistance across high-current load draws up to 300A.

• Flexible Protective Insulating Cap: Weatherproof elastomeric red cover insulates exposed conductor surfaces against accidental mechanical shorts.

• Ignition Protected: Safe for installation aboard gasoline-powered vessels when used with ABYC-compliant sealed MRBF fuses.