Blue Sea Systems ST Blade Fuse Block, 6 Independent Circuits, 32V DC, ATO/ATC

Overview

The Blue Sea Systems ST Blade Fuse Block is a 6-circuit fuse block for organizing and protecting small DC branch circuits on boats. It accepts ATO and ATC blade fuses and is rated for up to 32V DC, which makes it suitable for common 12V and 24V marine electrical systems. Each circuit is rated up to 30A, with up to 40A per jumped circuit group when the included terminal block jumpers are used.

This fuse block uses independent circuit inputs rather than a built-in negative bus, so it works well where separate feeds are needed for different loads, switched circuits, or always-on circuits. Tin-plated copper fuse clips help resist corrosion in the damp, vibration-prone spaces where boat electrical gear often lives, such as consoles, electronics lockers, helm panels, and protected utility areas.

The covered version adds a clear insulating cover with label recesses and spare fuse storage, while the uncovered version keeps the layout more open for installations inside an already protected enclosure or panel.

Key features

• 6 independent fuse circuits for organizing multiple DC loads without a common source bus built into the block.
• Accepts ATO and ATC blade fuses, giving the installer easy access to common replacement fuse types.
• Rated up to 32V DC for use in typical 12V and 24V boat electrical systems.
• 30A maximum rating per circuit, with 40A maximum per jumped circuit group.
• Tin-plated copper fuse clips help reduce corrosion concerns in protected marine electrical spaces.
• Accepts ring or snap fork terminals for secure wiring at the block.
• Mounts with #8 screws and uses #8-32 screw terminals with captive star lock washers.
• Includes two terminal block jumpers for grouping circuits under shared feeds when the installation calls for it.

Variants

This fuse block is offered in two configurations. Both are 6-circuit ST Blade fuse blocks for ATO and ATC fuses, with the main difference being whether the clear insulating cover is included.

The covered option adds protection over the fuse area and supports circuit labeling, while the uncovered option leaves the fuse block open for installations inside a separate protected panel or enclosure.

• 5035, with cover: Yes. This version includes the clear insulating cover, which helps shield the fuse area, holds spare fuses, and gives the installer a place to label circuits.
• 5037, with cover: No. This version is the open fuse block configuration, suited to protected installations where a separate cover or enclosure is already part of the layout.

Installation and setup

Use this block where several small DC loads need individual fuse protection, such as electronics, lighting, pumps, accessories, or helm equipment. Because the circuits are independently sourced, the installer can separate feeds by function, such as one group for switched loads and another for circuits that need power at all times.

Fuses are sold separately, so fuse selection should match the connected load and the wire size used in the circuit. Terminal torque is 18 in-lb, and the wiring layout should leave enough service space to inspect and replace fuses without straining the conductors.

Compatibility and fit

This is a positive-side fuse block without a negative bus, so it does not replace a return bus bar. It should be paired with a suitable negative bus or grounding arrangement elsewhere in the DC system when the installation requires one.

The block is a good match for refits and new installations where inline fuse holders have become hard to trace. Consolidating the fuses in one labeled location makes troubleshooting cleaner, especially around the helm, cabin distribution area, or electronics panel.

What’s included

• ST Blade 6-circuit fuse block
• Two terminal block jumpers