LLNRK350 - 350Amp Fuse

LLNRK350 - 350Amp Fuse

When you're protecting a 350 Amp electrical circuit, there's little room for guesswork. You need a fuse that can handle normal operating demands, tolerate temporary startup surges, and respond effectively when an actual electrical fault occurs. That's where the Littelfuse LLNRK350 earns its place.

Another advantage that can matter over years of operation is low electrical resistance. By reducing resistance-related power losses, the POWR-PRO design helps support efficient system operation.

With a 350A continuous current rating, 250V AC maximum voltage, and 125V DC maximum voltage, the LLNRK350 is designed for demanding commercial and industrial applications. It also offers an upgrade path for certain existing Class H fuse block installations, subject to equipment compatibility and applicable electrical requirements.

Key Features and Benefits

• 350 Amp continuous current rating for appropriately sized electrical circuits
• Class RK1 current-limiting design helps reduce short-circuit damage.
• Dual-element construction provides dependable time-delay operation.
• Spring-loaded thermal overload element helps minimize nuisance openings.
• Accommodates temporary inrush currents from motors and transformers
• High AC interrupting capacity for demanding electrical applications
• Low-resistance construction helps reduce power consumption.
• Suitable for service entrance, main, feeder, and general-purpose branch circuits
• Non-indicating design for standard fuse protection applications
• Supports upgrades from certain Class H fuses in compatible existing fuse blocks

Technical Specifications

• Manufacturer: Littelfuse
  
• Catalog Number: LLNRK350
  
• Series: LLNRK
  
• Product Family: POWR-PRO
  
• Fuse Class: Class RK1
  
• Fuse Type: Dual-Element, Time-Delay
  
• Continuous Current Rating: 350 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
  
• Specified Holder Series: LFR25400
  
• Class H Fuse Block Compatibility: Permitted for certain existing installations when equipment ratings and compatibility requirements are satisfied
  

Material Compliance and Certifications

The Littelfuse LLNRK350 belongs to the POWR-PRO Class RK1 fuse family and is designed for current-limiting overload and short-circuit protection.

• RoHS Compliance: Verify against current Littelfuse material compliance documentation
• REACH Compliance: Verify against current Littelfuse material compliance documentation
• UL and CSA Certifications: Confirm applicable listings and approvals using current manufacturer documentation

For projects requiring specific regulatory approvals, material declarations, or certification records, verify the latest manufacturer information before installation.

Where It Works Best

• Service Entrance Electrical Equipment
• Main Power Distribution Circuits
• Industrial Feeder Circuits
• General-Purpose Branch Circuits
• Motor Circuits with High Starting Currents
• Transformer Protection Applications
• Solenoids and Electromagnetic Equipment
• Fluorescent Lighting Circuits
• Industrial Machinery and Equipment
• Commercial Electrical Distribution Systems
• Electrical Components with Temporary Inrush Currents
• Compatible Class H Fuse Block Upgrade Applications