Mersen Launches Class J Fused Switch

June 24, 2025

Mersen, a global expert in electrical protection and control for electrical power systems is excited to announce their Class J Fused Switch.

Mersen’s FS Series UL 98 Listed fused disconnect switch is 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.

Occupying less space than a standard fuse holder and traditional disconnect switch combination, it enables more streamlined panel designs, ease of installation, and improved off-the-shelf distribution availability when time and convenience matter most, making it an ideal choice for panel builders.

Available in 30A and 60A versions, the FS Series Class J Fused Switch includes lockout/tagout (LOTO) capability and integrated LED fuse status indication and comes with an IP20 rating. It features a smaller footprint compared to a traditional Class J disconnect with a max interrupting rating of 200kA. The Class J Fused Switch is UL 98 listed and suitable for use as a main/feeder device.

Designed to accept ALL standard 30 and 60A Class J fuses, Mersen’s Class J Fused Switch gives Panel builders flexibility in fuse manufacturer selection and an all-important space saving option when compared to standard fused disconnects.

Cost-saving benefits of the Mersen Class J Fused Switch include:

• Smaller, less expensive enclosure or additional component space for panel builders
• Fewer components = less cost
  • Less total cost than switches and fuse holders

Want to learn more about the Class J Fused Switch? Visit the Class J Fused Switch product page, download the datasheet, or download our new UL 508A brochure.