JLLN400 - 400Amp Fuse

JLLN400 - 400Amp Fuse

For a 400-amp Class T fuse, getting the current rating right is only one part of the picture. The Littelfuse JLLN400 offers a clear combination of characteristics: fast-acting operation, a current-limiting design, and knife-blade/bolt-in construction. For maintenance teams, electricians, and equipment owners working from your existing JLLN400 specification, those details provide a practical compatibility checklist.

Key Features and Benefits

• 400A continuous current rating: Provides a clear amperage specification to verify against the equipment requirements.
• Class T fuse: The fuse class is explicitly identified, helping narrow down the correct component for compatible equipment.
• Fast-acting operation: Littelfuse specifies an F (Fast-Acting) opening characteristic.
• Current-limiting design: Identified by the manufacturer as part of the JLLN400 family style.
• AC and DC voltage ratings: Rated for a maximum of 300VAC and 125VDC, giving you distinct ratings to check for the intended circuit.
• Knife-blade/bolt-in format: A defined physical configuration that should be checked along with the electrical specifications.
• Non-indicating: The JLLN400 does not include an indicating feature.

Technical Specifications

• Manufacturer: Littelfuse
  
• Catalog Number: JLLN400
  
• Series: JLLN
  
• Manufacturer Description: FUS 300V F/A CLASS T 400A
  
• Continuous Current Rating: 400A
  
• Fuse Class: Class T
  
• Opening Characteristic: Fast-Acting (F)
  
• Family Style: Current Limiting
  
• Maximum AC Voltage: 300VAC
  
• Maximum DC Voltage: 125VDC
  
• AC Interrupting Rating: 200,000A (200 kA) at 300VAC
  
• DC Interrupting Rating: 20,000A (20 kA) at 125VDC
  
• Size / Construction: Knife-Blade/Bolt-In
  
• Indicating: No
  
• Mounting Method: Fuse Block / Clip / Holder
  
• PG Holder: LFT30400 Series
  

Material Compliance and Certifications

The manufacturer specifications supplied for the JLLN400 included no specific UL, CSA, CE, RoHS, REACH, or other material-compliance or certification information. That does not establish that the product lacks any particular certification. If an approval or material-compliance requirement matters to the application, confirm it with current authoritative manufacturer documentation and the markings on the actual fuse.

Where It Works Best

The Littelfuse JLLN400 400A fuse is best for compatible electrical equipment that requires a 400A Class T, fast-acting, current-limiting fuse with knife-blade/bolt-in construction. Its clearly separated AC and DC ratings also make specification matching more straightforward: 300VAC with a 200 kA interrupting capacity, or 125VDC with a 20 kA interrupting capacity, depending on the equipment and circuit requirements.