Mersen D300521 - Square Body High-Speed Fuse Protistor® Size 71 aR 1250VAC IEC 1300VAC UL 400A With Striker Flush ends metric threads
Mersen

D300521

Alternate Item Number: PC71UD13C400TF


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Overview

The Mersen Protistor® D300521 is a high-speed fuse-link engineered for superior semiconductor protection in power conversion equipment, including inverters, converters, and motor drives. This Size 71, aR ultra-fast acting fuse features a square body design with flush ends and metric threaded terminals (M12 x 1.75), offering maximum flexibility in equipment design while ensuring secure mounting and compatibility with standard industrial hardware. Rated for 1250VAC (IEC) and 1300VAC (UL), this specific unit carries a 400A current rating, making it suitable for high-power applications where precise overcurrent protection is critical. It provides ultimate protection for diodes, thyristors, and IGBT devices, boasting a pre-arcing I²t of 38 kA²s and a clearing I²t of 308 kA²s at rated voltage. The fuse-links are constructed with die-cut silver-plated copper elements embedded in high-purity quartz sand to control arcing characteristics, resulting in a lower I²t and a high interrupting rating of 126 kA. All contact surfaces are silver-plated to minimize resistance and ensure reliable conductivity, while non-magnetic stainless steel hardware is utilized to prevent interference with magnetic fields in sensitive applications. The D300521 is equipped with a striker mechanism for integration with trip-indicating systems, enabling visual or remote indication of fuse operation for enhanced system monitoring and safety. Manufactured in the US at Mersen’s ISO 9001-certified facility, this fuse-link is a critical component for ensuring the reliability and safety of advanced power electronic systems. Its robust construction, precise operation, and compliance with IEC 60269-4 and UL 248-14 standards make it ideal for applications requiring fast and reliable overcurrent protection in demanding industrial environments.
  • Mersen Protistor® Size 71 aR Fuse-Link
  • Rated 400A, 1250VAC (IEC), 1300VAC (UL)
  • Ultra-fast acting for semiconductor protection
  • Square body with flush ends and metric threaded terminals
  • Includes striker for trip indication

Specifications

AC Voltage Rating
1300 V
Amperage Rating
400 A
Application
Protection of inverters, motor drives, UPS systems and similar 690V or less equipments.
Brand Name
Mersen
Case
Ceramic
Connection
End Contact with Threaded Holes
Mounting
Bolted
Size
2.91 x 2.01 x 2.22 in
Size
74 x 51 x 56.5 mm
Special Features
Multiple body sizes and terminals or blades combination aR Class according to IEC 60269-4 and VDE 636-23 Very low I²t for improved semiconductor protection Ultra fast acting Current limiting Superior cycling capability
Standard
IEC 60269-4 Compliance UL/CSA Recognized E76491 CCC GB 13539.4 for Asian market only
Sub Brand
Protistor®
Type
Square Body High-Speed Fuse-Links AC Protection
Type Of Indicators
Striker
Voltage Rating
1300 V
Wattage
76 W
Package Dimensions (L x W x H)
2.91 in x 2.01 in x 2.22 in
Package Dimensions (L x W x H)
74 mm x 51 mm x 56.5 mm
Package Weight (Imperial)
1.135 lb
Package Weight (Metric)
0.515 kg
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9F61 Size B Clips 1.6in

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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 about Mersen

What industries and applications are Mersen products used for?

Mersen products are used across diverse industrial sectors including solar power, electric vehicles, buildings/construction, industrial automation, power distribution, HVAC, elevators, telecommunications, and specialty manufacturing. Key application areas include circuit protection, surge protection, battery module protection, electrical safety systems, and power management for residential, commercial, and utility-scale installations.

What are the main product lines offered by Mersen?

Mersen offers five primary electrical power product lines: IEC and UL/CSA Fuses and Fusegear, Surge Protection, Low Voltage Disconnect Switches, Power Distribution Blocks, and Engineered Solutions. Their comprehensive range includes specialized components like high-speed fuses, modular fuse holders, surge arresters, and custom-engineered electrical protection systems for industrial and power management applications.

What are the key features of Mersen products?

Mersen products feature advanced electrical protection and power management solutions with key characteristics including finger-safe design, compact modularity, and high-performance safety features. Their product lines span electrical power components like fuses, surge protection, power distribution blocks, and specialized solutions for industrial, solar, and building applications. Critical features include UL/CSA approvals, high short-circuit current ratings, and innovative technologies like the Fuse Control™ program that minimize electrical risks and optimize system performance.

What environmental ratings do Mersen products have?

Mersen products meet rigorous environmental ratings across multiple standards, including UL 508A Type 1, 2, 3, 4, 4X, 12, and 13, CSA Type 1, 2, 3, 4, 4X, 12, and 13, and NEMA Type 1, 2, 3, 4, 4X, 12, and 13. They feature IEC 60529 IP66 protection, with enhanced UV inhibitors for outdoor weathering and operating temperatures ranging from -40°C to 130°C (-40°F to 266°F). These ratings ensure superior protection in wet, corrosive, and challenging industrial environments.

What accessories are available for Mersen products?

Mersen offers multiple accessories for their fuse blocks and systems, including safety pullers (DFC3M and DFC3LP), DIN-rail adapters (DRM), bus bars, auxiliary contacts, and specialized mounting hardware. Key accessories include the DFC3M safety puller for 1-1/2" x 13/32" midget or Class CC fuses, the DRM adapter for mounting 303 series fuse blocks on DIN-rail, and UltraSafe fuse module accessories like bus bars and auxiliary contacts that enable module interconnection and monitoring.

How are Mersen products typically installed?

Mersen products are typically installed in electrical distribution systems, control panels, and industrial automation environments using multiple mounting options. These include service entrance panel mounting, distribution panel installation, control panel DIN rail mounting, and custom engineered solutions like Fused Coordination Panelboards. Installation depends on the specific product type, such as fuses, surge protective devices, or switches, and is designed to provide electrical protection and circuit safety in various industrial and commercial applications.

What certifications and standards do Mersen products comply with?

Mersen products are certified to multiple international standards, including UL (Underwriters Laboratories), CSA (Canadian Standards Association), CCC (China Compulsory Certification), and EAC (Eurasian Conformity). Our products meet rigorous safety and performance standards for industrial applications across North America, China, Russia, and other global markets, ensuring compliance and reliability in electrical power and advanced materials solutions.

What technical support does Mersen offer?

Mersen provides comprehensive technical support through multiple channels, including technical experts located in your time zone who can assist with product selection, application guidance, and troubleshooting. Their Fuse Control™ program offers a free Fuse Inventory Audit & Analysis, and customers can access technical resources through their sales representatives and online platform ep.mersen.com.