Blue Sea Systems ST Glass 6 Circuit Fuse Block, 32V DC, 100A, AGC/MDL Fuses

Overview

The Blue Sea Systems ST Glass 6 Circuit Fuse Block is a compact DC fuse block for organizing up to six protected branch circuits on a boat. It is rated for 32V DC systems, with a maximum of 100A per block and 30A per circuit, making it a practical fit for many low-voltage marine loads such as electronics, cabin accessories, pumps, lighting circuits, and other fused DC equipment.

This ST Glass fuse block accepts AGC fast-acting, MDL time-delay, and other 3AG glass fuses. The clear polycarbonate cover protects the conductive parts, helps meet ABYC and USCG insulation requirements, and includes space for circuit labeling and spare fuse storage, which makes inspection and service easier in a helm, console, cabin locker, or other protected electrical area.

Key features

• Six fused circuits for consolidating DC branch protection in one organized location.
• Rated for 32V DC, with 100A maximum per block and 30A maximum per circuit.
• Accepts AGC, MDL, and other 3AG glass fuses for common marine DC circuit protection.
• Tin-plated copper buses and phosphor bronze fuse clips support the full 30A circuit rating.
• Clear polycarbonate cover insulates conductive parts and stores spare fuses inside the block area.
• Label recesses on the cover help keep circuits identified for troubleshooting and future service.
• Reinforced polycarbonate base and #8-32 screw terminals with captive star lockwashers support secure wiring connections.
• Mounts with #10 screws for installation on a flat electrical panel, bulkhead, or equipment board.

Variants

This product is offered in two configurations, both based on the same ST Glass 6 circuit format with a protective cover.

The main difference is the negative bus. Both versions support the same 32V DC system rating, 100A block rating, 30A per circuit rating, AGC and MDL fuse compatibility, and #8-32 screw terminal style.

• 5015: Bus Type Negative Bus and Cover. This version combines the six fused positive circuits with an integrated negative bus, giving accessory negative returns a common landing point near the fuse block.
• 5018: Bus Type Cover. This version provides the six fused circuits with the protective cover, without an integrated negative bus, for installations where negative returns are handled on a separate bus bar.

Installation and setup

Install the block in a dry, accessible location where the cover can be removed and each fuse can be inspected without disturbing nearby wiring. Common locations include a helm electrical panel, electronics locker, cabin distribution area, or a protected equipment board near the loads being served.

Use wire size and fuse values that match the connected equipment and the circuit length. The fuse protects the wire, so each circuit should be sized for the load, conductor gauge, and installation conditions. The #8-32 screw terminals with captive star lockwashers help maintain firm connections in a marine environment where vibration is a normal part of service.

Compatibility and fit

This fuse block is for DC circuits up to 32V and is compatible with AGC, MDL, and other 3AG glass fuses. It works well where a boat already uses glass fuses or where the installer wants an organized block with labeling and spare fuse storage under the cover.

The version with a negative bus is better suited to compact wiring layouts where accessory negative wires need to return close to the protected circuits. The version without a negative bus fits systems that already use a separate negative bus bar or a larger DC distribution layout.