Blue Sea Systems ST-Blade Water-Resistant Fuse Block, 4 Circuit, 80A, 32V DC, IP66, ATO/ATC
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Overview
The Blue Sea Systems ST-Blade Water-Resistant Fuse Block is a compact 4-circuit fuse block for protected DC branch circuits on boats, built for ATO and ATC blade fuses as well as ATO/ATC-style low-profile circuit breakers.
It is rated for 32V DC systems, with 80A maximum per block and 25A maximum per circuit. The tin-plated copper C11000 bus and fuse clips help keep electrical connections organized in damp marine spaces where corrosion control and clean wiring matter.
The block uses #8-32 screw terminals with captive star lock washers, accepts one 8 AWG to 4 AWG input wire and four 16 AWG to 10 AWG load wires, and has mounting holes with clearance for 1/4 in. or 6 mm screws. It works well for small DC distribution runs feeding electronics, pumps, lighting, accessories, and other fused loads where a covered, water-resistant installation is needed.
Key features
- Four fused branch circuits in a compact block for organized DC distribution on boats.
- 32V DC maximum rating with 80A total block capacity and 25A maximum per circuit.
- Accepts ATO and ATC fast-acting blade fuses, plus ATO/ATC-style low-profile circuit breakers.
- Water-resistant layout with three wire plugs included to help maintain the rating when fewer than four loads are installed.
- Tin-plated copper C11000 bus and fuse clips for electrical contact surfaces suited to marine wiring environments.
- #8-32 screw terminals with captive star lock washers for ring or spade terminals using standard tools.
- Single-side nesting layout lets wiring enter from one side, which helps reduce clutter in tight helm, console, locker, and service-panel spaces.
- Cover includes spare fuse and fastener storage, with four write-on circuit labels for quick circuit identification.
Variants
This fuse block is offered in two cover configurations. The electrical layout, circuit count, voltage rating, amperage rating, terminal type, bus material, and accepted fuse and breaker styles remain consistent across the variants.
The main difference is the cover style. Both versions keep the circuits covered, while the manual-cover version adds wing screws for tool-free cover access and is listed as meeting ABYC/USCG insulation requirements.
- 5056: Cover type standard. This version uses the standard cover configuration for installations where cover removal with normal service access is acceptable.
- 5056100: Cover type manual cover. This version uses a manual cover with wing screws, so the cover can be secured and removed without tools during inspection or fuse service.
Installation and setup
Mount the fuse block where the cover can be opened and the circuit labels can be read during service. The compact footprint and one-side wire entry are useful behind dashboards, inside consoles, under protected lockers, or near small accessory distribution points where wiring space is limited.
Use properly sized marine wire, crimped terminals, and circuit protection matched to each load. The block accepts one main input conductor from 8 AWG to 4 AWG and four load conductors from 16 AWG to 10 AWG, so it is best suited to grouped low-voltage branch circuits rather than large main distribution loads.
Compatibility and fit
This fuse block is for DC systems up to 32V and is suitable for both 12V and 24V boat electrical systems when the connected loads, wiring, and fuses are sized correctly. It accepts common ATO and ATC blade fuses, which makes replacement straightforward during routine maintenance or troubleshooting.
Fuses and circuit breakers are sold separately, so each circuit can be matched to the actual load on the boat. The included write-on labels help keep bilge pumps, electronics, lighting, washdown pumps, and accessory feeds easy to identify later.
Use cases on board
This fuse block is a good match for boat owners and installers adding a small group of protected circuits in an area exposed to spray, humidity, or routine washdown. It is especially useful where a standard uncovered fuse holder would leave wiring less organized or harder to service.
For refits, electronics additions, fishing accessories, cabin upgrades, or helm wiring cleanup, it gives each branch circuit a clear location, visible label, and covered fuse position without taking up much panel space.
Shipping
We ship worldwide from the United States. Rates are calculated at checkout based on destination and package weight. Some items include free shipping, which will show automatically. Not every product is eligible for international shipping; checkout will confirm eligibility. We do not ship to PO Boxes except through USPS, and not all packages qualify.
Processing and dispatch
Most orders are verified, packed, and handed to the carrier within 1 to 2 business days. Some products may need extra handling time or ship directly from the manufacturer. For certain international orders, inventory transfers between warehouses may add time. If any delay is expected, we will let you know the dispatch date.
Delivery and tracking
Deliveries are handled by trusted carriers such as USPS, UPS, FedEx, and DHL. Estimated arrival times appear at checkout and depend on your location and the service you choose. These are estimates and can be affected by customs or carrier disruptions. A shipping confirmation with a tracking link is emailed when your order ships, and tracking may take up to 24 hours to update. You can also view tracking in your account.
Duties, taxes, and support
International customers are responsible for any customs duties, taxes, and fees charged by the destination country. If these charges are refused and a shipment returns to us, the carrier’s return cost and any re-entry customs fees will be deducted from the refund. If your order is late or you need help, contact cs@qualityboatparts.com and we will assist you.
Quality Boat Parts is a reseller. Many items include a manufacturer’s warranty, and all warranty service is handled directly by the manufacturer. We do not manage or administer warranty claims on behalf of customers.
Warranty terms, coverage, and duration are set by each manufacturer. Issues involving defects, repairs, or replacements must be addressed with the manufacturer’s support team. When available, the warranty period is listed on the product page. If it is not shown, contact us or the manufacturer for details before purchasing.
To start a claim, the customer must contact the manufacturer and follow their process. Keep your proof of purchase and original packaging, and register the product if the manufacturer requires it, as these are often needed for warranty service.
We are happy to help you find the right contact or documentation, but we cannot decide outcomes or intervene in claim resolutions. For guidance, email cs@qualityboatparts.com.