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 is a circuit protection specialist and technical writer with application-focused experience in technical support and custom protection design. He contributes practical, application-driven insights to the OptiFuse Blog.