Mersen K302091 - Square Body High-Speed Fuse Protistor® Size 72 gR 600VDC IEC 650VDC UL 350A With Striker Flush ends metric threads
Mersen

K302091

Alternate Item Number: D72GB60V350TF


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Overview

The Mersen K302091 Protistor® Size 72 gR high-speed fuse-link (SKU K302091) is a precision-engineered component designed for superior semiconductor protection in demanding power conversion applications. This square body fuse-link features flush ends with metric threads and is rated for 350A continuous current with a breaking capacity of 150kA at 600VDC/650VDC, meeting both IEC 650VDC and UL 600VDC standards. Constructed with pure silver fuse elements die-cut and embedded in solidified sand, the K302091 achieves exceptional arc control, resulting in lower I²t values for enhanced protection of sensitive components including diodes, thyristors, GTOs, and IGBTs. All contact surfaces are silver-plated for optimal conductivity, while non-magnetic hardware ensures long-term reliability in critical systems. The integrated striker mechanism enables low-voltage trip signaling through a field-mountable microswitch, providing immediate fault indication without manual inspection. With a pre-arcing I²t of 23.2 kA²s and clearing I²t of 140 kA²s, this fuse-link delivers precise fault response while maintaining high interrupting ratings. The metric threaded terminals ensure secure installation in equipment layouts requiring precise dimensional control. Part of Mersen's Protistor® series, the K302091 offers engineers flexibility in system design while providing the ultimate protection for high-power semiconductor applications where failure is not an option.
  • 350A rated current with 150kA interrupting rating at 600VDC/650VDC
  • Square body design with flush ends and metric threaded terminals
  • Pure silver fuse elements for low I²t and precise fault response
  • Striker mechanism enables trip-indicator integration for fault signaling
  • Meets IEC 650VDC and UL 600VDC standards for global compliance

Specifications

Amperage Rating
350 A
Application
Protection of inverters, motor drives, UPS systems and similar 600V or less equipments.
Brand Name
Mersen
Case
Ceramic
Connection
End Contact with Threaded Holes
Current Rating
350A
DC Voltage Rating
650 V
Material
Silver
Mounting
Bolted
Mounting Type
metric threads
Series
Protistor
Size
2.91 x 2.32 x 2.48 in
Size
74 x 59 x 63 mm
Size
Size 72
Special Features
Multiple body sizes and terminals or blades combination gR Class according to IEC 60269-4 and VDE 636-23 Low I²t for improved semiconductor protection Extremely fast acting Eliminate all overloads Excellent cycling capability
Standard
IEC 60269-4 Compliance UL/CSA Recognized E76491 CCC GB 1359.4
Sub Brand
Protistor®
Type
Square Body High-Speed Fuse-Links DC Protection
Type Of Indicators
Striker
Voltage Rating
600VDC
Voltage Rating
650 V
Wattage
58 W
Package Dimensions (L x W x H)
2.91 in x 2.32 in x 2.48 in
Package Dimensions (L x W x H)
74 mm x 59 mm x 63 mm
Package Weight (Imperial)
1.618 lb
Package Weight (Metric)
0.734 kg
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Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20

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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 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.