Mersen A70QS50-14FI - These Premium Amp-trap French Cylindrical Semiconductor Fuses are an extension of the popular A70QS product line. They are solid-fill 14mm and 22mm fuses IEC rated 690VAC, 200kA Interrupting and 700VDC, 100kA interrupting at 10ms time constant. In addition, these fuses have an 890 VDC rating for capacitor discharge applications up to 2.5ms time constant. All ampere ratings are available with a striker. Applications include small inverter drives and UPS systems, with superior I²t for improved protection and performance. 690 Volts 50 amps 14x51 ferrule w/striker.
Mersen

A70QS50-14FI

Alternate Item Number: 782001142216

UPC: 782001142216

Contact for Pricing

Overview

The **Mersen A70QS50-14FI Premium Amp-trap French Cylindrical Semiconductor Fuse** is a high-performance protection solution engineered for the most demanding industrial and power electronics applications. Part of Mersen’s renowned **A70QS series**, this **50A fuse** delivers unmatched reliability, precision, and safety in environments where electrical faults can pose catastrophic risks. Designed for **690VAC** systems with a **200kA interrupting rating**, it provides robust protection against overcurrent and short-circuit events, ensuring optimal performance in critical infrastructure such as **inverter drives, UPS systems, and semiconductor manufacturing equipment**. Engineered with a **solid-fill 14mm cylindrical design** and a **striker mechanism**, the A70QS50-14FI enhances system safety by enabling remote indication of fuse operation, reducing downtime and maintenance costs. Its **14x51mm ferrule** ensures seamless compatibility with standard fuse holders, simplifying installation and replacement in existing systems. Beyond AC applications, this fuse supports **700VDC at 100kA interrupting** and **890VDC for capacitor discharge applications up to 2.5ms**, making it a versatile choice for hybrid power systems and renewable energy installations. The **superior I²t characteristics** of the A70QS50-14FI ensure rapid response to fault conditions, minimizing thermal stress and extending the lifespan of downstream components. This is particularly critical in **high-frequency switching applications**, where even microsecond delays in fault detection can lead to equipment damage. Mersen’s **semiconductor-grade fuses** are trusted by industries such as **solar power, wind energy, electric vehicle charging, and industrial automation**, where reliability and precision are non-negotiable. Selecting the right fuse involves balancing **interrupting rating, voltage rating, and time-current characteristics** to match the specific demands of the application. The A70QS50-14FI excels in scenarios requiring **high interrupting capacity (HRC) and low let-through energy**, ensuring that sensitive electronics remain protected without unnecessary tripping. Its **striker feature** adds an extra layer of safety by triggering alarms or shutdowns when a fuse operates, preventing secondary damage in critical systems. Mersen, a global leader in electrical protection and thermal management solutions, has built a reputation for innovation and durability. With decades of expertise in **semiconductor fuses, circuit protection, and power electronics**, the company’s **Amp-trap series** is the preferred choice for engineers and maintenance professionals worldwide. Whether you’re designing a new system or retrofitting an existing one, the **Mersen A70QS50-14FI** delivers the performance, safety, and peace of mind required for mission-critical applications. Trust Mersen to keep your operations running smoothly—even in the harshest electrical environments.
  • 50A rated for 690VAC with 200kA interrupting capacity
  • Supports 700VDC (100kA) and 890VDC (capacitor discharge) applications
  • Solid-fill 14x51mm cylindrical design with striker for remote indication
  • Superior I²t characteristics for rapid fault response and component protection
  • Compatible with inverter drives, UPS systems, and semiconductor applications

Specifications

Amperage Rating
50 A
Application
Small inverters, UPS systems, Solid State Relays, motor drives and similar 700V or less equipment
Brand Name
Ferraz Shawmut
Connection
Ferrule
Connection Type
Ferrule
Current Rating
50 A
Material
Semiconductor Fuse
Mounting
Clip
Series
A70QS
Size
14x51 mm
Special Features
International 14 x 51mm (2 In x 9/16 In) and 22 x 58mm (2-1/4 In x 13/16 In) sizes for worldwide acceptance Ferrule mount for design versatility Very low I2t for improved semiconductor protection 690V IEC rated, tested at 760VAC, can be used up to 750VAC in U.S. 700VDC rated for dc protection of equipment with L/R <= 10ms/c Superior cycling ability for longer life on difficult cyclic loading applications
Standard
UL Recognized Component CSA Certified IEC 269-4 Compliance
Type
North American Round Style
Type Of Indicators
Striker
Voltage Rating
690 VAC
Package Dimensions (L x W x H)
2 IN x 0.55 IN x 0.55 IN
Package Dimensions (L x W x H)
5.08 cm x 13.97 mm x 13.97 mm
Package Weight (Imperial)
0.050 L
Package Weight (Metric)
0.023 kg
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Fuse Block 600VAC 600VDC Class CC 30A 1/4in Quick Connect / Solder 90 angle screw Knob Panel Mount
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20

C331156

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 1-Pole Visual Indicator Microswitch Pressure Plate IP20
Fuse Block 1500VAC 1500VDC 400A 1-Pole Stud M8

1SCM8

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.