Mersen 20657 - Fuse Block 250VAC 250VDC Class H/K 60A 2-Pole Copper Box
Mersen

20657

Alternate Item Number: 20657

UPC: 782001663780


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Overview

The Mersen 20657 is a Class H/K 250VAC/250VDC 60A 2-pole fuse block designed for industrial power distribution systems requiring reliable overcurrent protection. This fuse block features copper box connectors and clips, engineered specifically for copper wiring to match thermal expansion characteristics, ensuring long-term reliability under heat cycling conditions. The 2-pole configuration supports Class H and K fuses, with spring-reinforced clips for enhanced contact stability and reduced heat generation. The insulator is molded glass-filled polycarbonate (GFPC) with verified dielectric strength exceeding 2500V, providing robust electrical insulation. The 20657 accommodates wire ranges from #2 to #14 AWG, making it suitable for medium-duty industrial applications. Designed to meet OEM 'no aluminum' specifications, this fuse block ensures compatibility with copper conductors only, reducing corrosion risks and improving system longevity. Ideal for panelboards, motor control centers, and distribution boards in manufacturing, mining, and utility sectors where Class H/K fuse protection is required.
  • 250VAC/250VDC rated, 60A continuous current capacity
  • 2-pole Class H/K fuse compatibility with spring-reinforced clips
  • Copper box connectors and clips for copper wiring only (meets OEM 'no aluminum' specs)
  • Glass-filled polycarbonate (GFPC) insulator with >2500V dielectric strength
  • Accommodates #2-14 AWG wire range for versatile industrial applications

Specifications

AC Voltage Rating
250 V
Amperage Rating
60 A
Brand Name
Mersen
Class
Class H/K
Connection
Copper Box
Connection Type
Screw, Pressure Plate, Box, Stud
Current Rating
60A
DC Voltage Rating
250 V
Material
Copper Box, Glass-Filled Polycarbonate (GFPC) or Phenolic
Material
Glass Filled Polycarbonate
Maximum Operating Temperature
80 C
Mounting
Direct Screw Mount
Number Of Poles
2-pole
Phase
2
Poles
2
Series
Class H/K
Size
4.75 x 2.77 x 2.12 in
Size
120.65 x 70.358 x 53.848 mm
Standard
All fuse blocks meet the requirements of UL 4248 UL listed, guide IZLT, File E52283 UL recognized component guide IZLT2, file E52283 CSA certified class 6225, File 32169
Type
UL/CSA Fuse Bases
Voltage Rating
250 VAC
Package Dimensions (L x W x H)
4.75 in x 2.77 in x 2.12 in
Package Dimensions (L x W x H)
120.65 mm x 70.358 mm x 53.848 mm
Package Weight (Imperial)
0.450 lb
Package Weight (Metric)
0.204 kg
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The new Littelfuse Class H blocks offer many advantages over previous generations that are noted in the features and benefits section. Class H and Class R fuse blocks are dimensionally the same, but Class R blocks incorporate a rejection feature, which only allows Class R fuses to be inserted.
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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.