Mersen Q085252 - Square Body High-Speed Fuse Protistor® Size 121 gR 750VDC IEC 250A With Striker Flush ends metric threads
Mersen

Q085252

Alternate Item Number: D121GC75V250TF


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Overview

The Mersen Protistor® Size 121 gR (SKU: Q085252) is a high-speed fuse-link engineered for superior DC protection in demanding industrial and railway applications. Rated for 750VDC and 250A, this IEC 60269-4 compliant fuse delivers fast response times to safeguard semiconductor devices, DC traction systems, battery energy storage, and photovoltaic inverters. Its integrated striker mechanism provides visual fault indication and triggers system shutdown, reducing downtime in critical operations. Designed for elevated temperature environments, the Q085252 minimizes I²t values during short-circuit events, protecting downstream components from thermal damage. With a low power dissipation of 560W at rated current, it ensures energy efficiency and extended service life. The compact square body design optimizes panel space while offering a high breaking capacity of up to 200kA for robust fault interruption. Key features include flush ends with metric threads for secure mounting, compatibility with Mersen’s Protistor® series, and compliance with IEC standards for semiconductor protection. Ideal for modern DC power systems, this fuse-link combines reliability, precision, and durability in a single, space-saving package. Applications include industrial power electronics, DC traction systems, and renewable energy installations where high-speed fault protection is critical.
  • Rated 750VDC, 250A with high breaking capacity up to 200kA
  • Integrated striker for fault indication and system shutdown
  • Flush ends with metric threads for secure, space-saving installation
  • Low power dissipation (560W) for energy efficiency and extended service life
  • IEC 60269-4 compliant for semiconductor and DC protection applications

Specifications

Amperage Rating
250 A
Application
Protection of inverters Protection of motor drives Protection of UPS systems Railway power and auxiliary circuits Similar 750VDC or less equipments
Brand Name
Mersen
Case
Ceramic
Connection
End Contact with Threaded Holes
DC Voltage Rating
750 V
Mounting
Bolted
Size
5.16 x 2.01 x 2.17 in
Size
131 x 51 x 55 mm
Special Features
Multiple body sizes and terminals or blades combination Very low I²t Extremely fast acting Eliminate all overloads Excellent cycling capability
Standard
IEC 60269-4 Compliance
Sub Brand
Protistor®
Type
Square Body High-Speed Fuse-Links DC Protection
Type Of Indicators
Striker
Voltage Rating
750 V
Wattage
46.7 W
Package Dimensions (L x W x H)
5.16 in x 2.01 in x 2.17 in
Package Dimensions (L x W x H)
131 mm x 51 mm x 55 mm
Package Weight (Imperial)
1.940 lb
Package Weight (Metric)
0.880 kg
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Fuse Holder Modulostar® Size 10x38 IEC 690VAC 690VDC 3-Pole IP20

E1062696

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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.
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.