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Fuse Sizing Guidelines

Some of our manuals ask you to calculate the short circuit amperage rating or cold cranking amperage rating of your battery bank in order to determine the type of fuse necessary in an installation. Fuses are rated by both their Ampere Interrupting Capacity (AIC) as well as the better known, current trip level rating. This can be very confusing. Here is a much better explanation


For batteries with a less than 650CCA or 2700 short circuit amps, you may use an ANL type fuse of the correct current trip rating as listed in the manual for your properly sized battery cables.


For batteries with more than 650CCA or 2700 short circuit amps, you must use a Class T fuse of the correct current trip rating as listed in the manual for your properly sized battery cables.


It is acceptable to use a Class T fuse in all applications, so if you are having a problem determining the ratings of your batteries, feel free to use a Class T fuse. These fuses are available from most RV or Marine supply stores or from our Outlet Store.
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