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MRBF Fuse and HolderThe cube style MRBF fuse shown above is probably not getting the credit it deserves. The acronym MRBF stands for “Marine Rated Battery Fuse.” This fuse is perfect for complying with some of the newer ABYC standards that apply to over-current protection for battery banks. This fuse will also work well with really large battery banks too, where AIC (ampere interrupt capacity) limits can be reached pretty easily with modern new-age battery technology. Just as a reminder, AIC ratings describe how much amperage a fuse or circuit breaker can be exposed to and still be able to open the circuit when called upon. These “cube” fuses fill the bill nicely with an AIC rating of 10,000 amps at 14 VDC. The nominal rating of these fuses ranges from 30-300 amps so even as “whole bank” protection for a one or two paralleled battery configuration we are still in a very safe spot in terms of ratings. Besides the AIC rating, the fuse is rated as ignition protected, checking off another important key point when it comes to batteries. As a bonus, these little guys are also weather-proof rated to an IP-66 level, meaning that it is dust tight, but more importantly protected against a powerful jet spray of water. Its important to remember that all the goodness with these fuses relies on them being installed in the holder as shown above, so no short-cuts on that count please! Our sponsor Blue Sea Systems is a primary supplier of these powerful little fuses to our industry so they are now readily available.

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