Littelfuse KLNR004 - KLNR/KLSR series RK1 fast-acting fuses were the earliest type of current-limiting fuse developed. Their single-element, silver link design enables them to provide fast-acting overload and short-circuit protection. When used to protect inductive loads such as motors, solenoids, and transformers, KLNR/KLSR series fuses must be greatly oversized to prevent opening the fuses on harmless inrush currents. In such applications, KLNR/KLSR series fuses may only provide short-circuit protection. We recommend using POWR-PRO™ LLNRK/LLSRK series RK1, dual-element, time-delay fuses in all new applications requiring the current-limiting ability of UL Class RK1 fast-acting fuses, or in existing applications where fast-acting RK1 or RK5 fuses have been opening on harmless system surges such as motor starting currents.
Littelfuse

KLNR004

Alternate Item Number: KLNR004.T

UPC: 079458280531

Documents & Media
BrochureTechnical BulletinTechnical DrawingSpecification Sheet

Contact for Pricing

Overview

The Littelfuse KLNR004, part of the established KLNR/KLSR series, represents an early and effective design in current-limiting fuse technology. Engineered with a single-element, silver link construction, this RK1 class fuse delivers exceptionally fast-acting protection against both overloads and short-circuit events. Its rapid response time is crucial for safeguarding sensitive industrial equipment and electrical systems from potentially damaging current surges. While the KLNR004 excels in providing swift overload and short-circuit interruption, it's important to consider its application with inductive loads. For systems incorporating motors, solenoids, or transformers, the inherent inrush currents during startup can cause nuisance tripping if the fuse is not adequately oversized. In such scenarios, the KLNR004 may primarily serve as a robust short-circuit protection device, with its fast-acting nature necessitating careful sizing to avoid unnecessary operational interruptions. Littelfuse, a recognized leader in circuit protection, offers this fuse as a reliable component for general industrial applications where immediate fault interruption is a priority. For new installations or existing systems experiencing issues with harmless system surges, Littelfuse strongly recommends their POWR-PRO™ LLNRK/LLSRK series. These dual-element, time-delay fuses are specifically designed to accommodate inrush currents while still providing the essential current-limiting capabilities of UL Class RK1 fuses. This advanced design ensures optimal protection without compromising operational continuity. Key Features and Considerations: * **Fast-Acting Protection:** The single-element silver link design ensures rapid response to overcurrents. * **UL Class RK1:** Meets stringent industry standards for current-limiting performance. * **Industrial Applications:** Suitable for a wide range of manufacturing and processing environments. * **Inductive Load Considerations:** May require oversizing to prevent nuisance tripping due to inrush currents. * **Manufacturer Reputation:** Littelfuse is a trusted global leader in circuit protection solutions, known for quality and reliability. When selecting fuses for critical industrial infrastructure, understanding the specific load characteristics is paramount. The KLNR004 offers a foundational level of protection that has served industries reliably for years. However, for applications demanding a more nuanced approach to inrush current management alongside robust fault protection, exploring Littelfuse's advanced dual-element time-delay solutions is advisable. The KLNR004 remains a dependable choice for applications where its specific performance profile aligns with the system's requirements, ensuring the integrity and longevity of electrical equipment.
  • Single-element, silver link design for fast-acting response.
  • Provides essential overload and short-circuit protection.
  • UL Class RK1 certified for current-limiting performance.
  • Ideal for general industrial electrical system protection.
  • May require oversizing for inductive loads to prevent nuisance tripping.

Specifications

Amperage Rating
1 AMP
Application
DC control circuits/Solar
Brand Name
Littelfuse
Special Features
Fast-Acting
Standard
UL 2579 IEC 60269-6
Sub Brand
POWR-GARD KLKD Series
Type
UL Supplemental

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.