Class J Fuses and Fuse Holders

The Mersen FS Series is a UL 98 Listed fused disconnect switch designed for branch circuit protection using any UL Listed Class J fuse. Engineered for performance and convenience, the FS Series delivers the high interrupting capacity of Class J fuses (200kA SCCR) in the same footprint of a fuse holder. It occupies less space than a standard fuse holder and traditional disconnect switch combination, enabling more streamlined panel designs and improved off-the-shelf distribution availability when time and convenience matter most. Available in 30A and 60A versions, the FS Series includes lockout/tagout (LOTO) capability and integrated LED fuse status indication.

Mersen UltraSafe Modular 600 Volt Fuse Holders for Class J fuses introduce a new level of safety and ease for installing or replacing Class J fuses. UltraSafe holders qualify as “finger-safe” to an IP20 grade of protection under IEC standards. The US3J accommodates 30A Class J or 22 x 58 mm French Ferrule* fuses. The US6J is for 60A Class J fuses. UltraSafe holders are available in compact 1, 2, or 3 pole units, with or without blown-fuse indicators in each pole. Multi-pole units can also be made up in the field by using the multiplepole Assembly Kits. All units have provisions for locking in the open position for safety during fuse changeouts or equipment servicing. US3J and US6J holders can be snap-mounted to 35 mm DIN-rail and they have a unique latch which will stay open to allow re-positioning of the holder in the future. UltraSafe body material is tough and durable polyamide.
*Holder not UL listed when installed with French Ferrule fuses.
RECOMMENDED FUSE USAGE:
*US3J, US6J use with AJT, A4J, HSJ

Mersen UltraSafe Modular 600 Volt Fuse Holders for Class J fuses introduce a new level of safety and ease for installing or replacing Class J fuses. UltraSafe holders qualify as “finger-safe” to an IP20 grade of protection under IEC standards. The US3J accommodates 30A Class J or 22 x 58 mm French Ferrule* fuses. The US6J is for 60A Class J fuses. UltraSafe holders are available in compact 1, 2, or 3 pole units, with or without blown-fuse indicators in each pole. Multi-pole units can also be made up in the field by using the multiplepole Assembly Kits. All units have provisions for locking in the open position for safety during fuse changeouts or equipment servicing. US3J and US6J holders can be snap-mounted to 35 mm DIN-rail and they have a unique latch which will stay open to allow re-positioning of the holder in the future. UltraSafe body material is tough and durable polyamide.
*Holder not UL listed when installed with French Ferrule fuses.
RECOMMENDED FUSE USAGE:
*US3J, US6J use with AJT, A4J, HSJ

The High Speed Class J (HSJ) combines the low I2t of a semiconductor fuse and the branch-circuit performance of a Class J UL Listed fuse into a single design. The HSJ can provide both branch circuit protection per NEC requirements, as well as very low I2t for protection of power semiconductors such as Diodes, SCRs, GTOs and SSRs.

Mersen’s new Generation 2 open style class J fuse blocks accommodate class J fuses ranging from 0-100A, 600V. A choice of screw, pressure plate, and box connectors fit a wide range of stranded or solid wire. Gen2 fuse blocks are DIN-rail mountable, more compact than the traditional offering, and feature dovetail nesting for multipole field assembly. Fuse bases are IP20 rated when paired with Mersen’s newly designed dead front covers.

Mersen’s connectors fit a wide range of stranded or solid copper
or aluminum conductors. Insulators are either molded glass-filled
polycarbonate (GFPC) or phenolic with verified dielectric strength
in excess of 2500V. All fuse clips are made of high conductivity tinplated
copper designed specifically for 200-600A bladed Class J
fuses.

Mersen’s new Generation 2 open style class J fuse blocks accommodate class J fuses ranging from 0-100A, 600V. A choice of screw, pressure plate, and box connectors fit a wide range of stranded or solid wire. Gen2 fuse blocks are DIN-rail mountable, more compact than the traditional offering, and feature dovetail nesting for multipole field assembly. Fuse bases are IP20 rated when paired with Mersen’s newly designed dead front covers.

AJT Reducer Fuses are a safe permanent solution for decreasing your current rating without using a fuse reducer which are designed and list for temporary use only. These reducer fuses provide the same trusted protection levels as a traditional AJT fuses but in a larger body.

Amp-Trap fast-acting A4J fuses deliver excellent current-limiting protection to a wide variety of applications. Their unique dimensions prevent the substitution of other fuses with lower voltage ratings, interrupting ratings, or current-limiting capability.

Amp-Trap 2000® AJT fuses provide non-indication as well as a SmartSpot visual open fuse indicator. With advanced material technology the AJT fuse provides IEC Type 2 No Damage protection to main, feeder, and branch circuits, for all types of loads — yet, they require only half the mounting space needed for 600VAC Class RK fuses. AJT’s time-delay characteristics are ideal for handling typical motor and transformer inrush currents, while also providing superior current-limiting ability.