Littelfuse LA70Q400-4 - VERY FAST-ACTI SEMICOND FUSE Q400-4. Littelfuse LA70Q semiconductor protection fuses feature a 500 volt AC/DC rating in a compact size (11/2” x 13/32”). LA70Q also has the lowest I2t of all similar fuses and excellent cycling ability. Applications includeinverters and small equipment requiring extremely fast response to faults, without the need to carry sustained heavy overloads. Features: Lowest I2t of any fuse this size for greater protection. Excellent cycling ability gives advantage in equipment design.
Littelfuse

LA70Q400-4

Alternate Item Number: LA70Q4004

UPC: 079458153224

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Overview

The **Littelfuse LA70Q400-4** is a high-performance, very fast-acting semiconductor protection fuse engineered for critical applications where rapid fault response is essential. Designed to safeguard sensitive electronic components in inverters, power supplies, and small industrial equipment, this fuse combines a **500V AC/DC rating** with a compact form factor (1.5" x 0.406") to deliver unmatched protection without compromising space efficiency. **Key Features & Benefits:** - **Ultra-Low I²t Rating:** The LA70Q400-4 offers the **lowest I²t** of any fuse in its class, ensuring superior protection against transient faults and short circuits. This minimizes thermal stress on downstream components, extending their operational lifespan and reducing maintenance costs. - **Excellent Cycling Ability:** Unlike conventional fuses that degrade over repeated fault events, this Littelfuse model excels in applications requiring frequent cycling. Its robust design maintains consistent performance even under repeated overload conditions, making it ideal for dynamic environments. - **Wide Voltage Compatibility:** With a **500V AC/DC rating**, the LA70Q400-4 supports both alternating and direct current applications, providing versatility for global industrial and commercial systems. - **Compact Footprint:** Measuring just **1.5" x 0.406"**, this fuse fits seamlessly into space-constrained designs, allowing engineers to optimize panel layouts without sacrificing protection. **Industry Applications:** The LA70Q400-4 is a trusted choice for professionals in industries where semiconductor protection is non-negotiable. Typical applications include: - **Power Inverters:** Protects IGBTs, MOSFETs, and thyristors in solar, wind, and motor drive systems from catastrophic failure due to overcurrent events. - **Industrial Automation:** Safeguards control systems, PLCs, and variable frequency drives (VFDs) in manufacturing and robotics. - **Medical Equipment:** Ensures reliability in diagnostic devices, surgical tools, and imaging systems where downtime is unacceptable. - **Renewable Energy Systems:** Critical for grid-tied inverters, battery management systems, and energy storage solutions. - **Telecommunications:** Provides surge protection for sensitive networking hardware in data centers and telecom infrastructure. **Why Choose Littelfuse?** Littelfuse is a global leader in circuit protection, with over a century of innovation in fuse technology. The LA70Q series, including the LA70Q400-4, reflects the company’s commitment to precision engineering, rigorous testing, and adherence to international standards. Professionals rely on Littelfuse for: - **Proven Reliability:** Decades of field-proven performance in mission-critical applications. - **Technical Support:** Access to expert application engineers for selection, sizing, and installation guidance. - **Global Distribution:** Widely available through authorized distributors, ensuring quick procurement and minimal lead times. - **Compliance:** Meets UL, IEC, and other regional safety certifications for seamless integration into compliant designs. **Selection & Installation Considerations:** When choosing a semiconductor fuse, engineers must balance response time, breaking capacity, and physical constraints. The LA70Q400-4 excels in scenarios where **fast-acting response** is prioritized over sustained overload handling. For optimal performance: - **Sizing:** Select a fuse with an ampere rating slightly above the normal operating current to avoid nuisance tripping while ensuring rapid fault interruption. - **Mounting:** Ensure proper clearance and heat dissipation, as semiconductor fuses operate at high temperatures during fault conditions. - **Coordination:** Pair with downstream protection devices (e.g., circuit breakers or relays) to create a layered defense strategy against faults. For applications demanding the highest level of semiconductor protection, the **Littelfuse LA70Q400-4** delivers uncompromising performance, reliability, and efficiency. Whether protecting a solar inverter, industrial motor drive, or medical device, this fuse is a trusted solution for engineers who refuse to compromise on safety or performance.
  • 500V AC/DC rating for versatile applications
  • Ultra-low I²t for superior fault protection
  • Excellent cycling ability for repeated overloads
  • Compact 1.5" x 0.406" size for space efficiency
  • Trusted Littelfuse quality for critical systems

Specifications

Application
Protection of Semiconductors
Brand Name
Littelfuse
Series
LA70Q
Size
1.5" x 0.406"
Special Features
Very-Fast Acting
Standard
UL Recognized
Sub Brand
LA Series
Type
Semiconductor Fuse
Voltage Rating
500 V AC/DC
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.