Overview
The Littelfuse FLSR 12 is a Class RK5 dual-element, time-delay cartridge fuse designed for industrial and commercial electrical systems. The FLSR series dual-element, time-delay UL Class RK5 fuses are the most widely used fuse class. This model features a 200,000 Amp VAC RMS Symmetrical interrupting rating and measures 13/16″ diameter × 5″ length.
Key Features
- Provides excellent protection for all types of circuits especially those containing motors
- Dual-element design ensures advanced short-circuit and overload protection
- Precision manufactured parts ensure an accurate, consistent response to overloads and short-circuits
- Time-delay construction minimizes nuisance trips on motor inrush
- Cartridge terminal type with rejection design for safe insertion
Technical Specifications
The FLSR 12 meets UL Standard 248-12 and is certified for use in Class RK5 applications:
- Voltage Rating: 600VAC / 300VDC
- Current Rating: 12A
- Interrupting Rating: 200,000 Amp VAC RMS
- Terminal Type: Cartridge, rejection style
- Construction: Dual-element, time-delay
- Dimensions: 13/16″ Diameter × 5″ Length
- UL Listing: Class RK5
Typical Applications
The Littelfuse FLSR 12 is suitable for a range of industrial and commercial applications, including:
- Motor branch circuits and motor feeders
- General industrial equipment protection
- HVAC systems and compressor circuits
- Pump and fan motor protection
- Control panel and distribution board installations
Compatibility & Replacements
Compatible With
- Class RK5 fuse holders and blocks rated 600VAC
- Motor control centers (MCC)
- Industrial distribution panels
- Equipment requiring UL Class RK5 cartridge fuses
- Systems rated for 600V or lower
Replaces / Drop-In Replacement For
- Littelfuse FLSR012 (non-indicator variant)
- Littelfuse FLSR 12 standard class models
- Other 12A Class RK5 dual-element cartridge fuses meeting UL 248-12
Works With
- All standard Class RK5 rated fuse carriers and rejection blocks
- Equipment listed for Class RK5 protection devices
- Motor circuits and general-purpose industrial applications
- Complies with NEC Article 240 fuse requirements
