Mersen B220824 - Square Body High-Speed Fuse Protistor® Size 120 gR 750VDC IEC 50A With Striker Flush ends metric threads
Mersen

B220824

Alternate Item Number: D120GC75V50TF


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Overview

The Mersen Protistor® Size 120 gR high-speed DC fuse (SKU: B220824) offers superior semiconductor protection for critical DC power and auxiliary circuits. Engineered for demanding applications in railway, industrial, and renewable energy sectors, this fuse is designed to withstand elevated operating temperatures. It features a 750VDC rating and a 50A current capacity, with a pre-arcing I²t of 2700 A²s and clearing I²t of 90 kA²s, ensuring minimal damage to protected components during short-circuit events. The rated breaking capacity is 50 kA, and its power dissipation at 50A is 8.5W, contributing to low watts loss and extended service life for modern DC equipment requiring precise thermal and electrical stability. This square body fuse is designed for easy installation with flush metric threads and includes a striker for visual or remote fault indication, facilitating quick diagnostics in critical systems. Its compact 26x60mm footprint and 80g weight make it suitable for space-constrained panels while adhering to IEC standards for high-speed semiconductor protection. Typical applications include traction power units, battery management systems, DC link protection in converters, and auxiliary circuits in rail transit. The B220824 is compatible with Mersen’s Protistor® series accessories, ensuring system-level reliability in harsh environments where uptime and fault tolerance are paramount.
  • Semiconductor-grade high-speed DC protection
  • 750VDC rated voltage, 50A current
  • Square body design with flush metric threads
  • Integrated striker for fault indication
  • Compact 26x60mm footprint, 80g weight

Specifications

Amperage Rating
50 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
metric threads
Current Rating
50 A
DC Voltage Rating
750 V
Mounting
Bolted
Mounting Type
Flush ends
Series
Protistor®
Size
Size 120
Size
5 x 1.57 x 1.77 in
Size
127 x 40 x 45 mm
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
8.1 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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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.