AJT20 – GOULD 20A 600V CLASS J TIME DELAY FUSE

The AJT20 is a time-delay (dual-element) Class J fuse. Unlike fast-acting Class J fuses, it can tolerate brief motor inrush currents and other temporary overload surges without nuisance blowing — making it the preferred choice for motor and transformer protection. Both types share the same Class J rejection-style dimensions and 200kA interrupting rating at 600V.

The Gould AJT series has been continued under the Mersen (formerly Ferraz Shawmut) brand, so the Mersen AJT20 is a direct manufacturer replacement. Other functionally equivalent Class J time-delay options include the Bussmann LPJ-20SP and the Littelfuse JLLN020. Contact our team and we can help source the right replacement or an approved equivalent for your application.

No. Class J fuses use a rejection-style blade configuration specifically designed to prevent installation in Class H, K, or R holders. You must use a UL-listed Class J fuse holder or disconnect switch rated for Class J fuses. Installing a Class J fuse in the wrong holder is a code violation and a safety hazard — if you're unsure about your existing holder, send us the model and we'll verify compatibility.