Authorized Littelfuse Distributor
Littelfuse KLLU3500 - KLLU series UL Listed, time-delay, Class L are quality fuses in every sense of the word. They were developed to provide a somewhat lower priced alternate to the POWR-PRO™ KLPC series fuses. KLLU series fuses meet or exceed all UL requirements for Class L fuses. For superior protection and performance, specification-grade POWR-PRO™ KLPC series fuses are the recommended fuses.

Littelfuse KLLU3500 KLLU series UL Listed, time-delay, Class L are quality fuses in every sense of the word.…

Alternate Item Number: KLLU3500X

UPC: 079458017465


Documents & Media
BrochureTechnical BulletinTechnical Drawing3D CAD Model (IGES)Specification Sheet

Contact for Pricing

Call +1 (262) 252-1600 (toll-free 877-268-3700) or email [email protected] for pricing and availability.

Overview

The Littelfuse KLLU3500 (SKU KLLU3500) is a UL Listed, time-delay Class L fuse engineered for reliable overcurrent protection in industrial power systems. Part of the KLLU series, this fuse provides a cost-effective alternative to the premium POWR-PRO™ KLPC series while meeting or exceeding all UL requirements for Class L fuses. Designed for commercial and industrial applications where robust electrical safety is critical, the KLLU3500 offers dependable protection against overcurrent conditions to ensure the longevity and reliability of your electrical infrastructure. Key specifications include a 600V AC voltage rating, 300V DC rating, and a 200kA AC interrupting rating, making it suitable for high-fault applications. The time-delay characteristic handles temporary inrush currents common in motor starts and inductive loads, minimizing nuisance tripping and ensuring continuous operational uptime. This makes it particularly suitable for protecting motors, transformers, switchboard mains, motor control center mains, and large motor branch circuits. The KLLU3500 is a current-limiting fuse, providing superior protection by reducing peak let-through current during fault conditions. It is easily coordinated with other system components, ensuring seamless integration into existing electrical protection schemes. With ampere ratings from 601A to 4000A, the KLLU3500 is available in a range of sizes to meet diverse application requirements. The KLLU series fuses are trusted for their quality and adherence to UL requirements, making the KLLU3500 a dependable choice for industrial electrical protection. Additional resources, including time-current (TC) curves and CAD drawings, are available at www.littelfuse.com/kllu for detailed technical specifications and installation guidance.
  • Time-delay design handles temporary inrush currents for motors and inductive loads
  • 600V AC / 300V DC voltage ratings with 200kA AC interrupting rating
  • Current-limiting technology reduces peak let-through current during faults
  • Available in ampere ratings from 601A to 4000A for diverse applications
  • Ensures continuous operational uptime with minimal nuisance tripping

Specifications

Amperage Rating
3500 Amps
Application
Service Switches/Switchboard Mains
Brand Name
Littelfuse
Current Rating
3500 A
Series
KLLU
Special Features
Time-Delay
Standard
248-10 UL Listed/CSA
Sub Brand
KLLU Series
Type
Class L
Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount

GPM-SRR90

Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount
Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20

C331156

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20
Fuse Block 600VAC 600VDC Class CC 30A 3-Pole Pressure Plate with Reinforced Clip

30323R

Fuse Block 600VAC 600VDC Class CC 30A 3-Pole Pressure Plate with Reinforced Clip
9F61 Size B Clips 1.6in

9F61BWW460

9F61 Size B Clips 1.6in
POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

LCC5

POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

Frequently Asked Questions

What is the interrupting rating of the KLLU3500?

The KLLU3500 has a 200kA AC interrupting rating, making it suitable for high-fault applications.

What voltage ratings does the KLLU3500 support?

The KLLU3500 supports 600V AC and 300V DC voltage ratings.

Is the KLLU3500 a current-limiting fuse?

Yes, the KLLU3500 is a current-limiting fuse that reduces peak let-through current during fault conditions.

What applications is the KLLU3500 suitable for?

The KLLU3500 is suitable for service switches, switchboard mains, motor control center mains, large motor branch circuits, and circuit breaker protection.

How does the time-delay feature benefit motor applications?

The time-delay feature allows the fuse to handle temporary inrush currents during motor starts, minimizing nuisance tripping and ensuring continuous operation.

What is the ampere rating range for the KLLU series?

The KLLU series offers ampere ratings from 601A to 4000A.

Is the KLLU3500 CSA certified?

Yes, the KLLU3500 is CSA certified (File: LR29862).

Frequently Asked Questions about Littelfuse

What certifications and standards do Littelfuse products comply with?

Littelfuse products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Customers can verify specific product certifications by consulting individual product datasheets on Littelfuse.com, which provide comprehensive details about standards compliance for each component.

What industries and applications are Littelfuse products used for?

Littelfuse products are critical for electrical protection and safety across multiple industrial sectors, including manufacturing, automation, power distribution, and electrical control systems. Their comprehensive product portfolio serves industries that require robust electrical protection, including motor and pump applications, solar installations, programmable logic controllers (PLCs), electrical switch panels, and critical infrastructure environments. Key product lines protect against overcurrent, voltage transients, ground faults, and temperature-related electrical risks, ensuring equipment safety and operational reliability.

What technical support does Littelfuse offer?

Littelfuse offers comprehensive technical support through multiple channels. Their Technical Hotline (800-TEC-FUSE) provides direct access to engineers who can help identify issues and recommend solutions. Additionally, Littelfuse offers extensive online Technical Resources at Littelfuse.com, including datasheets, product manuals, whitepapers, application guides, and online design tools. Their experienced product and application engineers also provide step-by-step support from design to installation.

What are the main product lines offered by Littelfuse?

Littelfuse offers comprehensive industrial protection and control product lines, including fuses, fuse holders, protection relays, temperature sensors, and electrical safety components. Their key product categories span surge protective devices, custom OEM products, electrical switch panels, medium voltage fuses, ground-fault protection relays, motor and pump protection devices, and temperature sensors. These products are designed to minimize electrical safety hazards, limit equipment damage, improve productivity, and safeguard personnel from electrical faults.

What are the key features of Littelfuse products?

Littelfuse products feature exceptional circuit protection technologies with key characteristics including UL/IEC safety standard compliance, low internal resistance, and advanced protective capabilities across multiple product lines. Their components provide critical protection for industrial systems, offering features like overcurrent protection, voltage transient suppression, and resettable protection devices with ultra-low resistance and compact designs. Key product lines include fuses, metal oxide varistors (MOVs), TVS diodes, PolySwitch devices, and specialized electronic protection components that enhance system reliability and safety.

What environmental ratings do Littelfuse products have?

Littelfuse products feature comprehensive environmental ratings, including NEMA Type 1, 2, 3, 3R, 4/4X, 12, and 13 certifications, as well as IP65 protection. These ratings ensure superior protection in diverse industrial environments, with an operating temperature range of -40°F to +131°F (-40°C to +55°C). Many products also include UV-stabilized materials and neoprene gaskets for enhanced durability in outdoor and challenging conditions.

What accessories are available for Littelfuse products?

Littelfuse offers several key accessories across their product lines, including fuse holders, voltage monitoring modules, and terminal connectors. Specific accessories include the LPSM003ZXID (indicating) and LPSM003Z (non-indicating) POWR-SAFE Dead Front fuse holders for Class CC and Midget-Style fuses, the VRM6048 voltage monitor accessory module, and female quick connect terminals (P1015 series) in various wire gauge sizes. These accessories are designed to enhance protection, monitoring, and connectivity for Littelfuse electrical components.

What is Littelfuse's warranty policy?

Littelfuse provides comprehensive warranty details on their official website at www.littelfuse.com/warranty. Customers should visit this page to review the specific warranty terms and conditions for their specific product lines. For direct warranty support or questions, customers can contact Littelfuse Technical Support at 1-800-TEC-FUSE or email [email protected].

What communication protocols do Littelfuse products support?

Littelfuse supports a comprehensive range of industrial communication protocols, including PROFIBUS, PROFINET, EtherNet/IP, DeviceNet, Modbus RTU, and CANopen. Our products provide flexible connectivity solutions across multiple industrial automation platforms, enabling seamless integration with various control systems and network architectures.

How are Littelfuse products typically installed?

Littelfuse products are typically installed using specialized mounting hardware like fuse holders, blocks, and panels designed for specific industrial applications. The POWR-SAFE Dead Front holders, for example, provide optimum protection for Class CC and Midget-Style fuses, supporting installations up to 600 VAC/DC. Installation often involves using precision terminals with strain relief, such as 0.25 in. female quick connect terminals, to ensure secure and safe electrical connections in industrial control systems.