The high speed J (HSJ) fuse combines the low I2t of a semiconductor fuse and the branch circuit performance of a class J UL listed fuse. This fuse was designed for the starting characteristics of solid state motor controllers. The HSJ can provide branch circuit protection per NEC requirements, as well as very low I2t for protection of power semiconductors such as diodes, SCR’s, GTO’s and SSR’s. Optimized over-load capability for withstanding elevated levels of current during electronic motor controller starts. Excellent cycling ability for frequent starts/stops without nuisance opening.