Littelfuse 274004 - FUSE 125V FM02A MIL MICRO FUSE 4A. Developed originally for the U.S. Space Program, MICRO™ fuse provides reliability in a compact design. The MICRO™ fuse is available in plug–in or radial lead styles and a complete range of ampere ratings from 0.002A to 5A to suit a wide variety of design needs. Features: Military grade available. High breaking capacity. Clear cover option to view fuse element status. Available from very low ampere of 0.002A to 5A. Plug-in with short or long leads option. Applications: Printed circuit boards and similar equipment. Electronic components.
Littelfuse

274004

UPC: 079458980400


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Specification Sheet

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Overview

The Littelfuse MICRO™ 4A 125V Fuse (SKU: 274004) is a high-reliability, compact circuit protection solution engineered for demanding electronic applications. Originally developed for the U.S. Space Program, this military-grade fuse delivers unparalleled performance in a space-saving design, making it ideal for mission-critical systems where failure is not an option. Manufactured by Littelfuse, a global leader in circuit protection with over a century of innovation, the MICRO™ series combines precision engineering with robust construction to safeguard sensitive electronic components from overcurrent conditions. This versatile fuse is available in both plug-in and radial lead configurations, offering flexibility for PCB-mounted or through-hole installations. The 4A rating at 125V provides precise protection for low-power electronics, including control circuits, sensors, and communication modules. A standout feature is the optional clear cover, which enables visual inspection of the fuse element without removal, reducing maintenance time and improving troubleshooting efficiency. The high breaking capacity ensures reliable operation even in high-fault scenarios, while the wide ampere range (0.002A to 5A) allows engineers to standardize on a single fuse family across multiple designs. Industries that benefit from the Littelfuse MICRO™ 4A 125V Fuse include aerospace, defense, industrial automation, telecommunications, and medical devices—where reliability, compactness, and compliance with stringent standards are paramount. The military-grade variant meets MIL-PRF-23419 specifications, ensuring compatibility with defense and aerospace applications. For printed circuit boards and similar equipment, this fuse provides a cost-effective, high-performance alternative to bulkier protection solutions, reducing board space while maintaining critical safety margins. Professionals select the MICRO™ series for its proven track record in extreme environments, including high vibration, temperature fluctuations, and electromagnetic interference. Installation is straightforward, with options for short or long leads to accommodate varying PCB layouts. Littelfuse’s global distribution network and technical support ensure rapid availability and expert guidance, making this fuse a trusted choice for engineers designing for reliability from the outset. Whether protecting power supplies, signal lines, or control circuits, the MICRO™ 4A 125V Fuse delivers consistent performance where it matters most.
  • Military-grade reliability originally developed for the U.S. Space Program
  • Available in plug-in or radial lead configurations with short/long lead options
  • Wide ampere range from 0.002A to 5A for versatile design applications
  • High breaking capacity with optional clear cover for visual element inspection
  • Ideal for PCB-mounted and through-hole installations in aerospace, defense, and industrial electronics

Specifications

Amperage Rating
4 A
Application
Electronic Components
Brand Name
Littelfuse
Connection Type
Plug-in or Radial Lead
Connection Type
Plug-in / Radial Lead
Current Rating
4 A
Mounting Type
PCB / Through-hole
Series
MICRO™
Series
MICRO™ FM02A MIL
Special Features
None
Standard
CSA Certified
Sub Brand
274 Series
Type
MICRO Fuse
Voltage Rating
125 V
250V PICO FUSE BULK M-PACK 4A. The PICO® II 263 Series Fuse is a specifically designed axial leaded fuse that achieves a 250V rating in a small package. Features: Very fast-acting. Small size. Wide current rating range (62mA- 15A). RoHS compliant. Halogen-free available. Wide operating temperature range. Low temperature rerating. 250V rating.

0263004.MXL

250V PICO FUSE BULK M-PACK 4A. The PICO® II 263 Series Fuse is a specifically designed axial leaded fuse that achieves a 250V rating in a small package. Features: Very fast-acting. Small size. Wide current rating range (62mA- 15A). RoHS compliant. Halogen-free available. Wide operating temperature range. Low temperature rerating. 250V rating.
Miniature fuse SMG - Fast Acting 350VAC 2.5A

SMG2-1/2

Miniature fuse SMG - Fast Acting 350VAC 2.5A

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.