Authorized Littelfuse Distributor
Littelfuse KLNR300 - 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 KLNR300 KLNR/KLSR series RK1 fast-acting fuses were the earliest type of current-limiting fuse…

Alternate Item Number: KLNR300.X

UPC: 079458280913


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Contact for Pricing

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

Overview

The Littelfuse KLNR300, part of the KLNR/KLSR series, represents an early and foundational design in current-limiting fuse technology. Engineered with a single-element silver link, this fast-acting fuse provides robust overload and short-circuit protection for industrial electrical systems. Its rapid response to fault conditions makes it critical for safeguarding equipment and personnel. When protecting inductive loads such as motors, solenoids, and transformers, the KLNR300 may require significant oversizing to prevent nuisance tripping from harmless inrush currents. In such applications, it primarily offers short-circuit protection. For applications demanding both current-limiting and time-delay characteristics, especially in new designs or to prevent nuisance tripping on system surges, Littelfuse recommends their POWR-PRO™ LLNRK/LLSRK series dual-element, time-delay fuses. The KLNR/KLSR series, including the KLNR300, features a silver link construction ensuring high conductivity and a predictable melting point for precise fault interruption. This series is a reliable choice for applications requiring fast response times and effective current limitation, contributing to the integrity and operational continuity of industrial power distribution and control systems. Key features include fast-acting protection for rapid interruption of overcurrents and short circuits, a single-element silver link for consistent performance, and current-limiting capability to reduce fault current magnitude and duration. Backed by Littelfuse, a global leader in circuit protection, the KLNR300 is a proven technology for general industrial power distribution, protection of electrical equipment sensitive to fast transients, and control circuits where rapid fault clearing is essential. Always consult application-specific guidelines when selecting fuses for inductive loads and consider Littelfuse's advanced dual-element time-delay fuses for optimal performance against nuisance tripping.
  • Fast-acting overload and short-circuit protection
  • Single-element silver link design
  • Current-limiting capability
  • Suitable for general industrial power distribution
  • Early and foundational current-limiting fuse technology

Specifications

Amperage Rating
5 AMP
Amperage Rating
5 A
Application
Control Circuits & Inst Protection
Brand Name
Littelfuse
Current Rating
300 A
Material
Silver
Series
KLNR/KLSR
Special Features
Fast-Acting
Standard
Supplemental Protection
Sub Brand
POWR-GARD BLF 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 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 types of fuses does Littelfuse offer for industrial applications?

Littelfuse offers UL Class fuses, high-speed fuses, medium voltage fuses, 10 x 38 mm fuses, and solar fuses.

What are high-speed fuses used for?

High-speed fuses protect critical power semiconductor devices against short circuits in applications like inverters, variable-speed drives, UPS, and DC drive systems.

What is the voltage and amperage range for 10 x 38 mm fuses?

10 x 38 mm fuses are available with ratings from 125 to 1000 volts and 1/10 to 30 amperes.

What is the maximum voltage for Littelfuse solar fuses and holders?

Littelfuse offers solar fuses and holders up to 1500 Vdc for both high-current and low-current applications.

What conditions do Littelfuse feeder protection relays guard against?

Feeder protection relays protect circuits from overcurrent, ground faults, phase loss, overload, and other detrimental conditions.

What is the Industrial Shock-Block® GFCI designed for?

The Industrial Shock-Block® GFCI is designed for people protection in industrial facilities and meets UL Standard 943C Class C and Class D.

How do high-resistance grounding systems benefit industrial facilities?

High-resistance grounding limits point-of-fault damage, eliminates arc-flash hazards, and prevents transit overvoltages associated with ground faults.

What do Littelfuse voltage monitors protect against?

Littelfuse voltage monitors provide protection against both supply line and load side faults when the motor is running.

What functions can Littelfuse timers and flashers control?

Timers and flashers can delay starting and stopping loads, and control cycling and sequencing of motors, pumps, compressors, heaters, and lighting.

How do Littelfuse arc-flash protection relays enhance safety?

These relays detect developing arc-flash incidents and send a trip signal to interrupt power before significant damage occurs.

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.