Mersen P085251 - Square Body High-Speed Fuse Protistor® Size 120 gR 750VDC IEC 125A With Striker Flush ends metric threads
Mersen

P085251

Alternate Item Number: D120GC75V125TF


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Overview

Mersen Protistor® Size 120 gR high-speed DC fuse-link (SKU: P085251) provides semiconductor-grade protection for critical DC power systems. Rated at 750 VDC and 125 A, this IEC-certified fuse-link is optimized for railway traction power circuits, auxiliary converters, and industrial DC distribution systems where rapid fault interruption is essential. The square body design with flush metric threads ensures secure mounting in compact enclosures, while the integrated striker offers visual and mechanical indication of fuse operation. Key performance metrics include an ultra-low pre-arcing I²t of 1310 A²s and clearing I²t of 10500 A²s at rated voltage, minimizing stress on protected components during short-circuit events. With a rated breaking capacity of 126 kA and power dissipation of 38 W at nominal current, this fuse-link maintains thermal stability in high-temperature environments typical of semiconductor applications. The gR (gated reverse) characteristic enables fast response to both forward and reverse polarity faults, making it ideal for regenerative braking systems and HVDC links. Designed for seamless integration with Mersen’s Protistor® family, this Size 120 fuse-link offers 30% lower watts loss compared to conventional semiconductor fuses. Typical applications include traction inverters, battery energy storage systems, and DC microgrids requiring 125 A continuous current and 750 VDC isolation. The flush metric thread connection (M8/M10 compatible) simplifies installation in DIN-rail or panel-mounted configurations. Backed by Mersen’s global semiconductor protection expertise, this fuse-link meets IEC 60269-4 compliance for railway and industrial DC systems. For optimal coordination in multi-tier protection schemes, pair with Mersen’s Size 70 or 71 Protistor® fuses in upstream positions.
  • IEC-certified high-speed DC fuse-link rated at 750 VDC and 125 A
  • Ultra-low pre-arcing I²t of 1310 A²s and clearing I²t of 10500 A²s
  • Rated breaking capacity of 126 kA with 38 W power dissipation at nominal current
  • gR (gated reverse) characteristic for fast response to forward/reverse polarity faults
  • Square body design with flush metric threads (M8/M10 compatible) for secure mounting
  • 38 W power dissipation at rated current for thermal stability
  • IEC 60269-4 compliant for railway and industrial DC applications
  • Compatible with Mersen Protistor® family for coordinated protection

Specifications

Amperage Rating
125 A
Application
Protection of inverters Protection of motor drives Protection of UPS systems Railway power and auxiliary circuits 750VDC or less equipments
Brand Name
Mersen
Case
Ceramic
Connection
End Contact with Threaded Holes
Connection Type
Flush metric threads (M8/M10 compatible)
Current Rating
125 A
DC Voltage Rating
750 V
Mounting
Bolted
Mounting Type
DIN-rail or panel-mounted
Series
Protistor®
Size
5 x 1.57 x 1.77 in
Size
127 x 40 x 45 mm
Size
Size 120
Special Features
Multiple body sizes and terminals or blades combination Very low I²t Extremely fast acting Eliminate all overloads Excellent cycling capability
Standard
EU conformity REACH compliant 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
21 W
Package Dimensions (L x W x H)
5 in x 1.57 in x 1.77 in
Package Dimensions (L x W x H)
127 mm x 40 mm x 45 mm
Package Weight (Imperial)
1.433 lb
Package Weight (Metric)
0.650 kg
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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.

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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.

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.