Littelfuse KLLU800 Class L Fuse – 800A – 600V Time-Delay Fuse

The Littelfuse KLLU800 is an 800 Amp Class L time-delay fuse designed for high-capacity industrial and commercial electrical distribution systems. Part of the KLLU series, this UL Listed fuse provides dependable overload and short-circuit protection while offering a cost-effective alternative to the POWR-PRO™ KLPC series. Its time-delay characteristics allow temporary motor starting currents and transformer inrush currents to pass without nuisance opening, ensuring reliable operation in demanding applications.

KLLU series fuses meet or exceed all UL requirements for Class L fuses and provide excellent protection for feeders, motors, switchgear, and large power distribution equipment.

Electrical Rating

• Current Rating: 800 Amps
• Maximum AC Voltage: 600 VAC
• Maximum DC Voltage: 300 VDC
• Interrupting Rating:
  • 200 kA AC @ 600 VAC

Key Specifications

• Manufacturer: Littelfuse
• Catalog Number: KLLU800
• Series: KLLU
• Fuse Class: Class L
• Construction Type: Bolt-In
• Fuse Type: Time-Delay (Slo-Blo)
• Family: Current-Limiting Fuse
• Indicating: No

Protection Characteristics

• Minimum 10-second time delay at 500% of rated current
• Accommodates motor starting currents and transformer inrush loads
• Current-limiting design reduces short-circuit damage to systems and equipment
• High 200 kA interrupting capacity provides superior fault protection
• Protects branch circuit conductors, motor control equipment, and motors
• Selective coordination with other Class L and Littelfuse current-limiting fuses
• Helps reduce downtime by isolating only the faulted circuit

Construction Features

• Heavy-duty bolt-in Class L fuse construction
• UL Listed and compliant with Class L fuse requirements
• Industrial-grade design for demanding electrical environments
• Cost-effective alternative to POWR-PRO™ KLPC series fuses
• Non-indicating configuration

Features & Benefits

• Current-limiting protection minimizes equipment damage during fault conditions
• Easily coordinated with other system protective devices
• 200 kA AC interrupting rating supports present and future system requirements
• Time-current characteristics closely match many circuit breaker curves
• Allows greater flexibility in breaker coordination than fast-acting Class L fuses
• Enhances equipment life and system reliability

Mounting & Compatibility

• Mounting Method: Bolt-In
• Compatible with Class L fuse clips, fuse blocks, and mounting hardware
• Suitable for switchboards, switchgear, feeder circuits, and distribution equipment

Applications

• Main service protection
• Feeder circuit protection
• Large motor circuits
• Transformer protection
• Industrial switchgear and switchboards
• Commercial and industrial power distribution systems
• Selectively coordinated electrical systems

Product Data

• Manufacturer: Littelfuse
• Catalog Number: KLLU800
• Product Type: Time-Delay Current-Limiting Fuse
• Series: KLLU
• Fuse Class: Class L
• Family: Current-Limiting Fuse