Mersen R642 - Fuse Reducer 600V Class R 400 - 600 400 - 600 400 - 600
Mersen

R642

Alternate Item Number: R642

UPC: 782001752446

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Overview

The Mersen R642 Fuse Reducer (SKU R642) is designed for 600V electrical systems, enabling the use of lower-amperage fuses within higher-rated fuse clips. This non-rejection type reducer allows Class H, K, or R fuses to fit into Class H or K fuse clips, enhancing circuit protection flexibility. It is crucial for applications like motor protection and renewable energy systems where precise fuse sizing to equipment nameplate current is vital for preventing damage from overcurrents and short circuits. By enabling closer fuse ratings, the R642 improves fault detection and interruption capabilities, extending equipment lifespan and minimizing downtime. Manufactured by Mersen, this reducer ensures reliable performance in industrial environments. The R642 is sold in pairs. It is tested to 200,000A and is UL Listed (Guide No IZZR) and CSA Certified. This reducer allows a 400A fuse to fit into 600A clips.
  • Enables use of lower-rated fuses in higher-rated fuse clips
  • Suitable for 600V Class R electrical systems
  • Allows 400A fuses to fit into 600A clips
  • Non-rejection type: accepts Class H, K, or R fuses in Class H or K clips
  • Tested to 200,000A, UL Listed (IZZR), CSA Certified

Specifications

AC Voltage Rating
600 V
Application
Mersen fuse reducers allow the use of lower rated fuses in existing equipment having clips with higher ampere ratings. The use of closer rated time-delay fuses can improve circuit protection. For example, renewable or one-time fuses feeding a motor can be replaced with fuses sized closer to the motor nameplate current. Non-rejection reducers will allow Class H, K or R fuses to fit Class H or K clips. Rejection-type reducers will allow only Class R fuses to fit Class R clips or only Class J fuses to fit Class J clips. Class J fuse reducers are not for bolt on applications.
Application
Start-up or newly expanding manufacturing facilities ramping up production and electrical demand Temporary use of reduced rating fuse
Brand Name
Ferraz Shawmut
Class
R
Current Rating
400-600 A
Size
2.75 x x 2 in
Special Features
Allow a reduced rating fuse to be installed in a larger fuse holder of the same fuse class Wide range of ratings and sizes
Standard
250V and 600V Class H, K, and R - UL Listed Guide No. IZZR, CSA Certified. 600V Class J - UL Listed Guide No. IZZR, CSA Certified 30-600A
Standard
UL Listed Guide No. IZZR CSA Certified
Type
Fuse Reducer
Type
Fuse Reducers
Voltage Rating
600 VAC
Package Dimensions (L x W x H)
3.15 IN x 2 IN x 0.187 IN
Package Dimensions (L x W x H)
8.001 cm x 5.08 cm x 4.7498 mm
Package Weight (Imperial)
0.400 L
Package Weight (Metric)
0.181 kg
Fuse Reducer 600V Class R 200 - 400

R422

Fuse Reducer 600V Class R 200 - 400

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.