Littelfuse KLNR050 - 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

KLNR050

Alternate Item Number: KLNR050.T

UPC: 079458280777

Documents & Media
BrochureTechnical BulletinTechnical DrawingSpecification Sheet

Contact for Pricing

Minimum Qty: 10

Multiplier: 10

*Contact for lower quantities*

Overview

The Littelfuse KLNR050, 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, this RK1 fast-acting fuse is specifically designed to deliver rapid and reliable overload and short-circuit protection across a range of industrial applications. Its inherent speed in responding to fault conditions makes it a critical component for safeguarding sensitive electrical equipment from damaging current surges. Historically, the KLNR/KLSR series fuses were among the first to offer current-limiting capabilities, providing a crucial layer of defense against electrical hazards. The silver link material is chosen for its excellent conductivity and predictable melting characteristics, ensuring consistent performance when protecting resistive loads. For applications involving inductive loads, such as motors, solenoids, and transformers, it is imperative to significantly oversize the KLNR050 fuse. This oversizing is necessary to accommodate the high inrush currents that these types of loads experience during startup, thereby preventing nuisance tripping. In such scenarios, the primary protective function of the KLNR050 becomes focused on robust short-circuit protection, offering a vital safeguard against catastrophic system failures. While the KLNR050 is a proven performer for specific applications, Littelfuse strongly recommends their POWR-PRO™ LLNRK/LLSRK series for new installations or for existing systems where fast-acting RK1 or RK5 fuses are experiencing nuisance tripping due to harmless system surges, like motor starting currents. The dual-element, time-delay design of the POWR-PRO™ series offers superior performance in these demanding situations, providing both overload and short-circuit protection with enhanced tolerance for inrush currents. The KLNR050 remains an excellent choice for applications where fast-acting protection is paramount and the potential for nuisance tripping on inductive load inrush is either managed through careful oversizing or is not a significant concern. Key Features and Considerations: * **Fast-Acting Protection:** Delivers rapid response to overloads and short circuits. * **Single-Element Silver Link:** Ensures consistent and reliable performance. * **RK1 Classification:** Meets stringent UL Class RK1 requirements for current-limiting fuses. * **Application Suitability:** Ideal for resistive loads and situations where inductive load inrush is not a primary concern or is managed. * **Manufacturer Trust:** Littelfuse is a globally recognized leader in circuit protection, known for quality and innovation. When selecting fuses for industrial electrical systems, understanding the load characteristics is paramount. The Littelfuse KLNR050 offers a foundational level of protection, particularly valuable in legacy systems or specific applications where its fast-acting nature is the primary requirement and its limitations with inductive loads are well understood and addressed. For advanced protection and broader application flexibility, exploring Littelfuse's time-delay fuse offerings is highly recommended.
  • Littelfuse KLNR050 RK1 fast-acting fuse from the KLNR/KLSR series.
  • Features a single-element, silver link design for rapid fault response.
  • Provides essential overload and short-circuit protection for industrial equipment.
  • Suitable for resistive loads; requires significant oversizing for inductive loads.
  • Trusted Littelfuse quality for reliable circuit protection.

Specifications

Amperage Rating
1.5 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
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 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 1500VAC 1500VDC 400A 1-Pole Stud M8

1SCM8

Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8
Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20
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.
9F61 Size B Clips 1.6in

9F61BWW460

9F61 Size B Clips 1.6in

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.