What is a Class J fuse? A Class J fuse is a 600 volt AC current limiting fuse that is rated to interrupt a minimum of 200,000 amps. Bussmann, Littelfuse and Mersen self-certify their Class J fuses to a 300,000 interrupting rating. Class J fuses are offered in fast acting or time delay versions. Ampere ratings for the J type fuses range from 1 to 600 amps. The Bussmann and Littelfuse time delay versions have a dual element construction. Blown fuse indication versions are also available. High speed versions of the J style fuse have similar opening speeds to a semiconductor fuse are offered by Mersen and Bussmann. Bussmann also offers a space saving finger safe CUBEFuse™ which has similar electrical characteristics to a Class J fuse. J type fuses are UL Listed under UL 248-8, Class J and CSA Certified.

We offer J style fuses from Bussman, Littelfuse and Mersen. Bussmann brand names used for Class J fuses are Low Peak® , Limitron® and CUBEFuse™. Littelfuse brand names used for Class J fuses are Power-Pro® and Indicator®. Mersen brand names are Amp-Trap®, Amp-Trap 2000® and SmartSpot®.

Browse our broad selection of the J type fuses in our data sheet finder.

An Assortment of Class J Fuses