LLNRK300 - 300Amp Fuse

LLNRK300 - 300Amp Fuse

A motor starts. Current jumps for a moment. Then everything settles into normal operation. That's how much electrical equipment works, and it's exactly why choosing the right fuse matters.

The LLNRK300 uses two protective elements, including a spring-loaded thermal overload element. This gives the fuse time-delay characteristics that help it tolerate temporary inrush currents from motors, transformers, and similar equipment without opening unnecessarily. When an actual overcurrent condition occurs, the fuse provides the protection your circuit needs.

Key Features and Benefits

• 300 Amp Continuous Current Rating
• Class RK1 Current-Limiting Protection
• Dual-Element Time-Delay Design
• Handles Temporary Motor Starting Surges
• Helps Minimize Unnecessary Fuse Openings
• High Short-Circuit Interrupting Capacity
• Helps Limit Fault Energy and Equipment Damage
• Low-Resistance Construction for Reduced Power Loss
• Spring-Loaded Thermal Overload Element
• POWR-PRO Series Performance
• Compatible Class H Fuse Block Upgrade Capability
• Fuse Block, Clip, or Holder Mounting

Technical Specifications

• Manufacturer: Littelfuse
  
• Catalog Number: LLNRK300
  
• Series: LLNRK
  
• Product Family: POWR-PRO
  
• Fuse Class: Class RK1
  
• Fuse Type: Dual-Element, Time-Delay
  
• Continuous Current Rating: 300 Amps
  
• Maximum AC Voltage: 250V AC
  
• Maximum DC Voltage: 125V DC
  
• AC Interrupting Ratings: 200,000A and 300,000A at 250V AC, as listed by Littelfuse
  
• DC Interrupting Rating: 20,000A at 125V DC
  
• Opening Characteristic: Slo-Blo / Time Lag / Time Delay
  
• Current-Limiting: Yes
  
• Overload Element: Thermally Reversible, Spring-Loaded
  
• Indicating: No
  
• Mounting Method: Fuse Block / Clip / Holder
  
• Compatible Holder Series: LFR25400
  
• Class H Fuse Block Compatibility: Suitable for certain existing installations when equipment ratings and compatibility requirements are met
  

Material Compliance and Certifications

The Littelfuse LLNRK300 is part of the POWR-PRO Class RK1 fuse family, designed for overload and short-circuit protection in appropriately rated electrical systems.

• RoHS Compliance: Confirm using current Littelfuse documentation
• REACH Compliance: Confirm using current Littelfuse documentation
• UL and CSA Certifications: Verify applicable listings and approvals with the manufacturer

For installations requiring specific safety certifications or material compliance documentation, consult the latest manufacturer specifications.

Where It Works Best

• Service Entrance Equipment
• Main Distribution Circuits
• Electrical Feeder Circuits
• General-Purpose Branch Circuits
• Industrial Motors
• Transformers
• Solenoids
• Fluorescent Lighting Circuits
• High-Inrush Electrical Equipment
• Commercial Electrical Systems
• Industrial Machinery
• Compatible Class H Fuse Block Upgrades