Fast-Acting Protection for Compact AC Circuits: The FSE Fuse
When you need quick, dependable overcurrent protection in tight spaces, OptiFuse’s FSE/FSE-P series delivers. This fast acting 5x15mm glass cartridge fuse (with optional axial-lead version) is UL 248-14 recognized and purpose-built for clear visual inspection and reliable interruption in low/medium-voltage AC circuits.
Highlights:
- Voltage ratings (model dependent) up to 300 VAC for select ratings; 250 VAC for others. See datasheet for more information
- Interrupting Ratings:
- 50A @ 300 VAC
- Form factor: 2AG / 5x15mm glass cartridge; optional FSE-P axial-lead variant.
Typical Applications
- AC power supplies, control boards, and instrumentation
- Appliance and small equipment branch protection
- Auxiliary AC circuits in panels requiring fast-acting response and visual fuse status, pair with the right fuse holder, see
Why Choose the FSE Series?
FSE combines a compact 2AG footprint with fast-acting performance and straightforward visual inspection, ideal when space is limited but compliance and reliability still matter. With UL 248-14 recognition and published AC interrupting ratings per amperage, it’s a practical, drop-in choice for a wide range of AC applications.
To learn how to select the right tube fuse, read our How to Choose a Tube Fuse article or see our Fuse Selection Guide for complete context.
Holder Tip
Pair FSE with CSC 5 mm fuse clips for compact PCB mounting. Match the clip’s current and temperature ratings to your application and verify the 2AG/5 mm size fit
Sebastian Castañeda, Application Engineer at OptiFuse, supports customers with technical solutions, custom circuit protection design, and training. He provides tailored guidance and shares expert insights on the OptiFuse Blog.