LLNRK040 - 40Amp Fuse

LLNRK040 - 40Amp Fuse

Electrical equipment needs protection that works when it matters, without interrupting operations during brief power surges. That's where the Littelfuse LLNRK040 40 Amp, 250V Class RK1 time-delay fuse comes in. Part of the Littelfuse POWR-PRO™ series, this dual-element, current-limiting fuse protects motors, transformers, feeder circuits, and other electrical equipment from damaging overloads and short circuits. The LLNRK040 is especially useful because it can handle temporary inrush currents, like those that occur when a motor starts, without opening unnecessarily. When a serious electrical fault occurs, its current-limiting design reduces the energy reaching your connected equipment, potentially preventing costly damage and downtime. Rated for 40 amps, 250V AC, and 125V DC, the LLNRK040 also offers an impressive 300,000-amp interrupting rating at 250V AC.

Key Features and Benefits

• 40 Amp Current Rating
• 250V AC / 125V DC Voltage Ratings
• Class RK1 Current-Limiting Protection
• Dual-Element Time-Delay Design
• Reduced Nuisance Fuse Opening
• Energy-Efficient Performance
• Flexible Mounting Options

Technical Specifications

• Manufacturer: Littelfuse
  
• Catalog Number: LLNRK040
  
• Product Series: LLNRK
  
• Product Family: POWR-PRO™
  
• Product Type: Current-Limiting Time-Delay Fuse
  
• Fuse Class: Class RK1
  
• Continuous Current Rating: 40 Amps
  
• Maximum AC Voltage: 250V AC
  
• Maximum DC Voltage: 125V DC
  
• AC Interrupting Rating: 300,000A at 250V AC
  
• Additional AC Interrupting Rating: 200,000A at 250V AC
  
• DC Interrupting Rating: 20,000A at 125V DC
  
• Opening Characteristic: Slo-Blo / Time-Delay
  
• Element Configuration: Dual-Element
  
• Fuse Indication: Non-Indicating
  
• Mounting Method: Fuse Block / Clip / Holder
  
• Compatible Holder Series: LFR25060
  
• Compatible Fuse Block Type: Suitable for Class RK1 and existing Class H fuse blocks
  

Material Compliance and Certifications

The Littelfuse LLNRK040 is part of the POWR-PRO Class RK1 fuse family, developed for electrical systems that need dependable overload and short-circuit protection.

• Material Compliance: Verify RoHS and REACH status with current manufacturer documentation
• Safety Certifications: Confirm applicable UL, CSA, and other approvals using the manufacturer's latest certification records

For installations with specific compliance requirements, check the manufacturer's documentation to confirm the applicable ratings, certifications, and material declarations.

Where It Works Best

• Industrial Motors
• Transformers
• Service Entrance Equipment
• Main and Feeder Circuits
• General-Purpose Branch Circuits
• Solenoids and Electromagnetic Equipment
• Fluorescent Lighting Systems
• Electrical System Upgrades