Blue Sea Systems MRBF Terminal Fuse, 58V DC, Ignition Protected, Clear Window

Overview

The Blue Sea Systems MRBF Terminal Fuse is a Marine Rated Battery Fuse for high-current DC circuit protection close to the battery, with amperage options from 30A to 300A and a maximum voltage rating of 58V DC. It is used with a compatible Blue Sea Systems Terminal Fuse Block and is not intended to be mounted directly to a battery terminal.

This fuse format is useful where battery cable protection needs to stay compact, such as DC main feeds, inverter circuits, windlass circuits, bow thruster circuits, and other high-load battery-based systems. Its interrupt capacity is 10,000A at 14V DC, 5,000A at 32V DC, and 2,000A at 58V DC, which supports proper protection on large battery banks when the fuse rating is selected to match the conductor and system design.

Each fuse has a clear window for checking blown condition and color coding by amperage, so service checks are faster in a battery compartment, engine space, or electrical locker. The fuse is ignition protected, making it suitable for installation aboard gasoline-powered boats when installed with the required fuse block and correct marine wiring practices.

Key features

• Marine Rated Battery Fuse format for compact protection near battery banks and high-current DC distribution points.
• Available amperage range from 30A to 300A for matching the fuse to the protected cable and connected load.
• 58V DC maximum voltage rating for use across common 12V, 24V, and 48V DC marine electrical systems within the rated limit.
• Interrupt capacity of 10,000A at 14V DC, 5,000A at 32V DC, and 2,000A at 58V DC.
• Ignition protected for use on gasoline-powered boats when installed correctly with the required terminal fuse block.
• Clear inspection window shows blown condition without removing the fuse from the installation.
• Color-coded amperage identification helps reduce confusion during maintenance or replacement.
• Requires Blue Sea Systems Terminal Fuse Block 5191 or 2151 for proper mounting and use.

Variants

This range varies by amperage rating, with options from 30A through 300A. The lower amperage versions are commonly selected for smaller DC branch or feed circuits, while the higher amperage versions are suited to larger battery cables and equipment loads when the conductor size and circuit design call for that rating.

The fuse format, maximum voltage rating, ignition protection, blown-fuse window, color-coded identification, and requirement for a compatible terminal fuse block remain consistent across the range. Final fuse selection should be based on the protected cable size, expected load, and the vessel electrical plan rather than the equipment name alone.

Installation and fit

This fuse must be installed on a compatible terminal fuse block, not directly on a battery post. That keeps the connection mechanically supported and gives the fuse the correct mounting arrangement for high-current service.

Because it is often installed close to batteries, clean cable routing and protected terminals matter. Check that the ring terminals, fuse block, torque values, cable size, and overcurrent protection plan match the vessel’s DC system before energizing the circuit.

Use cases on board

This fuse family is a practical match for boats with battery banks feeding heavy DC loads or main distribution points, especially where space around the battery switch, bus bar, or battery compartment is limited. It is commonly used in powerboats, sailboats, fishing boats, and cruising vessels that need high-current protection in a compact footprint.

What’s included

• One MRBF Terminal Fuse

Orders are processed within 2 business days, which includes verification, packing, and dispatch. Orders of $100 or more qualify for free shipping when eligible. For orders under $100, shipping costs are calculated at checkout based on destination, package weight, and selected service. International shipping is available for eligible products, and certain items may require additional handling, warehouse transfers, or may ship directly from the manufacturer, which can affect processing time.

Deliveries are handled by preferred carriers such as USPS, UPS, FedEx, DHL, and others depending on your location and selected service. Estimated delivery times are displayed at checkout and may vary due to customs processing, carrier delays, weather, postal disruptions, or other circumstances beyond our control. Once your order ships, you'll receive a confirmation email with tracking information. Tracking may take up to 24 hours to update on the carrier's website and is also available through your account when applicable.

We ship throughout the United States and to most international destinations for products eligible for international shipping. International orders may be subject to customs duties, taxes, brokerage charges, or other import fees, which are the customer's responsibility and are not included in the product or shipping price. PO Boxes are accepted only when shipping through USPS, and not all packages qualify for this option. If your order does not arrive within the estimated delivery window, please contact us at info@apollolighting.com or +1 (954) 375-0100 so we can assist with locating your package.

Learn more.

Returns may be requested within 30 days of receiving your order. Items must be unused, uninstalled, unaltered, and returned in their original packaging with all tags, packing materials, blank warranty cards, manuals, instructions, accessories, and included items. Certain products, including installed or used electronics, electrical components, lighting, consumables, custom or special-order items, cut-to-length products, safety equipment, and merchandise exposed to water or marine conditions, may not be eligible for return.

To request a return, sign in to your account and select the applicable order and items, and submit your request for review. Eligible unfulfilled items may also be submitted for cancellation within 1 hour of placing the order. Returns or cancellations are not considered approved until you receive confirmation from Apollo Lighting. Please do not ship or drop off merchandise before receiving return approval and instructions.

Customers are responsible for arranging and paying for return shipping unless the return is due to an error by Apollo Lighting or the item is verified as defective, damaged, or incorrect. Missing, damaged, defective, or incorrect items must be reported within 2 business days of delivery, and photos or other documentation may be required for review. If the issue is verified, Apollo Lighting may provide or reimburse return shipping and issue a replacement or refund depending on the circumstances. International customers are responsible for return shipping, duties, taxes, customs charges, brokerage fees, and other costs associated with an international return.

After your return is received and inspected, approved refunds are issued to the original payment method and may take 5-7 business days to appear after processing. Original shipping and handling charges are nonrefundable, and the value of any included free items that are not returned may be deducted from the refund. Apollo Lighting does not charge a standard restocking fee on eligible returns. Returns that are incomplete, damaged, installed, used, altered, improperly packaged, or otherwise do not meet the eligibility requirements may be refused. We recommend using a trackable and appropriately insured shipping service for all customer-arranged returns.

For assistance, contact info@apollolighting.com or call +1 (954) 375-0100.

Learn more.

Many products sold by Apollo Lighting include a manufacturer's warranty covering defects in materials or workmanship. Warranty terms vary by brand, product category, and model, so eligibility, coverage duration, exclusions, and available remedies are determined by the applicable manufacturer. We recommend reviewing the warranty information provided with your product before installation or use, especially for marine electronics, navigation equipment, lighting, electrical systems, pumps, safety equipment, and other specialized marine products.

If you need warranty service, the claim must follow the process established by the manufacturer, authorized service center, or designated warranty provider. You may be asked for proof of purchase, a serial number, product registration, photos, maintenance or installation records, or other documentation. Apollo Lighting does not determine or modify a manufacturer's warranty coverage or final claim decision, but we are happy to help provide purchase information and direct you to the appropriate manufacturer or warranty resource.

Keep your receipt, product documentation, serial number information, and original packaging when practical. Damage caused by normal wear, misuse, improper installation, insufficient maintenance, corrosion, impact, unauthorized modifications, electrical issues, or operation outside the manufacturer's specifications may not be covered. Warranty claims are separate from standard returns, so a product that has been installed, used, or exposed to marine conditions may no longer qualify for return while still remaining eligible for evaluation under the manufacturer's applicable warranty.

Learn more.