MRBF Terminal Fuse - 250A - Dimension Drawing

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Blue Sea Systems

5189-BSS

MRBF terminal fuse - 250 A

The Blue Sea MRBF 250A terminal fuse (5189-BSS) is designed to protect high-current circuits directly at marine battery terminals. It provides fast and reliable interruption in case of overload or short circuit, optimizing the safety of your electrical installation.

The product includes a 250A MRBF terminal fuse.

Retail priceBenefit from the professional rate

15,69€

15,69€ ~~19,10€~~

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Prices shown excluding VAT for Türkiye. If your delivery address is in the European Union, the VAT of the destination country will be added at checkout.

Low stock

Free pickup point from €150 in France
Pickup at Skysat possible

Custom installation

Trust Skysat to install the equipment on board

Request a quote

Installers near you

thanks to our network of approved installers

Find an installer

Support service

Opt for additional installation assistance

Technical specifications

Fuse type	MRBF
Nominal voltage	58 V DC
Amperage	250.0
Compatible fuse rating range	250 A
Short-circuit breaking capacity	10.0
Number of fuses	1.0
Mounting type	On stud
Stud size (mm)	M8
Terminal thread size (mm)	M8
Fuse included	Oui
Ignition protection	Oui
Flame retardant	Oui
ABYC compliance	Oui
Contact material	Tinned copper
Housing material	Thermoplastic UL 94V0 and Ceramic
Recommended terminal torque (Nm)	8.47
Maximum cable cross-section per stud	107.0
Dimensions (W x H x D)	27.8 x 16.3 x 23.0 mm
Weight	0.05
Operating temperature range	-40°F to +185°F
Certifications	ABYC,SAE J1171,IP66,UL
Application Environment	Mariner
Compact Design Benefit	Space saving, reduced footprint
Conductor Material Plating	Tinned
Fire Prevention Feature	Yes
Fuse Element Material	Copper
Integrated fuse holder	No
Ease of installation	High
Product design emphasis	Safety, compactness
Product robustness level	High
Product range	MRBF
Product type	Fuse

Detailed description

Designed for high-current circuit protection, the BLUE SEA MRBF 250A terminal fuse (5189-BSS) provides a compact and secure solution for marine electrical installations. This fuse mounts directly onto battery terminals or compatible distribution blocks, minimizing cable lengths and connection points, which reduces resistance and failure risk. It is specifically rated for a nominal current of 250 amperes, making it suitable for high-power equipment such as inverters, bow thrusters, or windlasses.

Optimal Protection for Marine Systems

The MRBF (Marine Rated Battery Fuse) design differs from traditional inline fuses like ANL or Class T by its form factor and mounting method. While ANL and Class T fuses require an external fuse holder and intermediate cables, the BLUE SEA MRBF 250A terminal fuse integrates directly onto the battery’s positive terminal. This design simplifies wiring, reduces space requirements in engine compartments or battery lockers, and minimizes the number of components needed for effective protection. It ensures rapid and reliable interruption in case of overload or short circuit, safeguarding the entire electrical system and preventing fire hazards.

Integration and Compatibility

The MRBF 250A terminal fuse is a key component in modern DC electrical protection systems. It belongs to the BLUE SEA product range, known for robust and reliable solutions for the marine environment. It can be used alongside other circuit protections in DC distribution installations, providing primary protection closest to the energy source. Its compact form factor is illustrated by scaled comparison diagrams, enabling precise planning of the space required for installation.

Documentation

Type	Nom
	EN - Comparatif échelle 1:1 - Fusibles terminal MRBF Blue Sea

Expert opinion

Pol CONIN

Digital Manager

« High-intensity protection for marine systems »

The BLUE SEA MRBF 250A terminal fuse is a strategic solution for protecting high-current circuits on vessels. Its unique design allows direct mounting on the battery’s positive terminal, which is crucial for minimizing the length of unprotected cables and thus reducing fire risks in the event of a short circuit between the battery and the first protection point. For applications such as bow thrusters, windlasses, or high-power inverters (250A being a significant current), this proximity to the source is a major safety advantage.

Installation is simplified: the fuse integrates directly into the terminal system, often replacing a standard nut on the battery stud or a compatible MRBF distribution block. This saves considerable space compared to classic inline fuse holders and their associated wiring. It is essential to ensure the battery stud or distribution block is compatible with the MRBF format for a secure and loss-free connection. This type of fuse is a wise choice for installations requiring robust and compact primary protection, but it does not replace secondary protection for lower-current distribution circuits.

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MRBF terminal fuse - 250 A

15,69€

15,69€ ~~19,10€~~

Frequently Asked Questions

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What is an MRBF terminal fuse and what is its primary function?

The MRBF (Marine Rated Battery Fuse) terminal fuse is an electrical protection device designed for high-current circuits in marine environments. Its primary function is to protect the entire electrical system from overloads and short circuits by quickly cutting off the current, thereby preventing fire risks and equipment damage.

What is the nominal current rating of this MRBF fuse and for which applications is it suitable?

This MRBF fuse has a rated current of 250 amperes. It is specifically sized to protect high-power equipment with high current draw, such as inverters, bow thrusters, windlasses, and other marine electrical systems requiring robust protection.

How is this MRBF fuse installed in a marine electrical system?

The MRBF terminal fuse is designed to be mounted directly on battery terminals or compatible distribution blocks. This design minimizes cable lengths and connection points, reducing electrical resistance and the risk of failure.

What are the advantages of the MRBF design compared to traditional inline fuses such as ANL or Class T?

The MRBF design offers several key advantages:

Direct integration: It mounts directly on the battery's positive terminal, unlike ANL or Class T fuses which require an external fuse holder and intermediate cables.Simplified wiring: This direct integration simplifies wiring and reduces the number of components needed.Reduced footprint: It minimizes space requirements in engine compartments or battery lockers.Optimized protection: It provides fast and reliable cutoff in case of overload or short circuit, effectively protecting the electrical system.

Is this fuse specifically designed for marine environments?

Yes, absolutely. The term "MRBF" stands for "Marine Rated Battery Fuse", indicating it is specifically designed and tested for the robustness and reliability required in demanding marine environments. It is part of the BLUE SEA product range, known for its reliable solutions for the nautical sector.

Is it possible to use this fuse with different battery brands or distribution terminals?

This fuse is designed to be mounted on standard battery terminals or compatible distribution blocks. As long as the terminal or block dimensions match the MRBF fuse mounting specifications, it should be compatible with most brands.

What precautions should be taken when installing an MRBF fuse?

When installing an MRBF fuse, it is essential to ensure the connection is secure and clean to guarantee optimal conductivity and avoid hot spots. The polarity must also be respected, and the appropriate tools must be used for correct tightening. Professional installation is always recommended for marine electrical systems.

Can this fuse be used to protect multiple circuits simultaneously?

The 250A MRBF fuse is designed to protect a main circuit or a group of high-current circuits connected to the same battery terminal or distribution block. If you need to individually protect multiple secondary circuits, it is recommended to use additional fuses or circuit breakers sized for each specific downstream circuit beyond the main MRBF fuse.