Littelfuse KLLU1200 Class L Fuse – 1200A – 600V Time-Delay Fuse

The Littelfuse KLLU1200 is a 1200 Amp Class L time-delay fuse designed as a cost-effective alternative to the POWR-PRO™ KLPC series while still meeting or exceeding UL Class L requirements. It is engineered for high-capacity industrial power distribution systems where reliable short-circuit protection, selective coordination, and motor inrush tolerance are required.

This fuse provides robust protection for feeders, large motors, and transformers, while maintaining a lower cost profile compared to premium specification-grade Class L options.

Electrical Rating

• Current Rating: 1200 Amps
• Maximum AC Voltage: 600 VAC
• Maximum DC Voltage: 300 VDC
• Interrupting Rating:
  • 200 kA AC at 600 VAC

Key Specifications

• Manufacturer: Littelfuse
• Catalog Number: KLLU1200
• Series: KLLU
• Fuse Class: Class L
• Construction Type: Bolt-In
• Fuse Type: Time-Delay (Slo-Blo)
• Family: Current-Limiting Fuse
• Indicating: No

Protection Characteristics

• Time-delay design provides at least 10-second delay at 500% of rated current
• Accommodates motor starting and inductive load inrush currents
• Current-limiting action reduces damage during fault conditions
• High interrupting rating (200 kA) ensures strong fault protection capability
• Supports selective coordination with other Class L and Littelfuse current-limiting fuses
• Helps reduce downtime by isolating only the faulted branch circuit

Construction Features

• Bolt-in Class L fuse construction
• Industrial-grade, heavy-duty design for high fault current environments
• Cost-effective alternative to KLPC series
• Designed for long service life and reliable system protection
• Non-indicating configuration

Mounting & Compatibility

• Mounting Method: Bolt-In
• Compatible with Class L fuse blocks and holders
• Used in switchboards, switchgear, and large industrial distribution systems

Applications

• Main and feeder circuit protection
• Large motor circuits
• Transformers and heavy inductive loads
• Industrial power distribution systems
• Switchgear and switchboards
• Selective coordination systems

Product Data

• Manufacturer: Littelfuse
• Catalog Number: KLLU1200
• Series: KLLU
• Fuse Class: Class L
• Family: Current-Limiting Fuse