Mersen L1028731 - DIN NH Standard fuse-link gTr Size NH4a 400VAC 577A 400KVA live tags Top indicator Body width 72.9 mm
Mersen

L1028731

Alternate Item Number: NH4AGTR400KVA-8


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Specification Sheet

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Overview

The Mersen L1028731 DIN NH Standard fuse-link gTr (Size NH4a) is engineered for transformer protection in low-voltage electrical systems. This high-breaking-capacity (HRC) fuse-link is rated for 400V AC, 577A nominal current, and 400KVA transformer capacity, making it ideal for industrial and commercial applications requiring reliable overcurrent protection. The fuse-link features live gripping-lugs and a top indicator for clear visual status, ensuring safe and efficient operation. Designed for the NH fuse system, the L1028731 integrates seamlessly with NH fuse-bases and replacement devices, providing a plug-in solution for quick maintenance and replacement. The gTr time/current characteristic is specifically optimized for transformer protection, offering superior selectivity compared to standard gG fuse-links. This ensures optimal coordination with downstream protective devices, reducing nuisance tripping and enhancing system reliability. The fuse-link can be continuously loaded up to 1.3 times its nominal current for up to 10 hours, making it suitable for applications with temporary overload conditions. It operates within 2 hours at 1.5 times the nominal transformer current, providing robust protection against fault conditions. With a body width of 72.9 mm and a power dissipation of 577W at nominal current, the L1028731 is built to handle demanding industrial environments. Manufactured by Mersen in France, the L1028731 meets IEC standards for low-voltage fuse systems, ensuring compliance with international safety and performance requirements. Its durable construction and precise engineering make it a trusted choice for protecting transformers, switchgear, and distribution panels in power generation, utilities, and heavy industrial facilities.
  • Rated for 400V AC, 577A nominal current, and 400KVA transformer capacity
  • gTr time/current characteristic optimized for transformer protection
  • Live gripping-lugs and top indicator for safe, visible status monitoring
  • Compatible with NH fuse-bases and replacement devices for easy maintenance
  • Body width 72.9 mm; can be loaded to 1.3x nominal current for 10 hours

Specifications

AC Voltage Rating
400 V
Amperage Rating
577 A
Application
Protection of transformers
Body Material
Ceramic
Brand Name
Mersen
Connection
Plain Blades
Connection Material
Silver-Plated Copper
Connection Type
Blade Contact
Current Rating
577 A
Interrupt Rating
100 kA
Mounting
Clip
Mounting Type
Plug-in
Series
NH
Size
7.87 x 2.87 x 4.8 in
Size
200 x 73 x 122 mm
Size
NH4a
Special Features
Maximum transformer capacity (up to 1,3 x In) Reduction of unnecessary interruption of operation Precise cut off of overload Characteristic adapted to the transformer Resistant to ageing Selectivity to fuse links gG High current limiting High breaking capacity Easy selection between transformer and fuse link
Standard
VDE 0636 Part 201 IEC 60269-1 and -2
Type
IEC NH Fuse-Links
Type Of Indicators
Top indicator
Voltage Rating
400 VAC
Package Dimensions (L x W x H)
7.87 in x 2.87 in x 4.8 in
Package Dimensions (L x W x H)
200 mm x 73 mm x 122 mm
Package Weight (Imperial)
4.850 lb
Package Weight (Metric)
2.200 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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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.