Mersen 166 Fuse Reducer 600V Class H, K 60 - 100
Alternate Item Number: 166
UPC: 782001752347
Documents & Media
Contact for Pricing
Call +1 (262) 252-1600 (toll-free 877-268-3700) or email [email protected] for pricing and availability.
Overview
- Enables lower-rated fuses (60A–100A) in higher-rated Class H/K fuse clips
- Non-rejection type accepts Class H, K, or R fuses into Class H/K clips
- Rated for 600V systems with 200,000A interrupting rating
- Improves circuit protection by allowing closer fuse sizing to load requirements
- Ideal for motor protection and industrial applications requiring precise overcurrent protection
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 | H & K |
Current Rating | 60-100 A |
Size | 1.84 x 0.01 x 0.75 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) | 1.84 IN x 0.9 IN x 0.9 IN |
Package Dimensions (L x W x H) | 4.6736 cm x 22.86 mm x 22.86 mm |
Package Weight (Imperial) | 0.020 L |
Package Weight (Metric) | 0.009 kg |
Frequently Asked Questions
What is the purpose of Mersen Fuse Reducers?
Mersen Fuse Reducers allow the use of lower rated fuses in existing equipment with higher ampere rated clips, improving circuit protection.
What is the voltage rating for Mersen Fuse Reducers?
Fuse Reducers are rated for 250V and 600V Class H, K, and R fuses, and for 600 Volt Class J fuses.
What is the amperage range for Mersen Fuse Reducers?
The amperage range for Mersen Fuse Reducers is from 30 to 600A.
Are Mersen Fuse Reducers UL listed and CSA certified?
Yes, Mersen Fuse Reducers are UL Listed under Guide No. IZZR and CSA Certified.
What is the safety note regarding Fuse Reducers?
Fuse Reducers are intended for temporary use only.
What types of fuses can Non-rejection Reducers accommodate?
Non-rejection Reducers will allow Class H, K, or R fuses to fit into Class H or K clips.
What fuses do Rejection-type Reducers allow?
Rejection-type Reducers allow only Class R fuses to fit Class R clips, or only Class J fuses to fit Class J clips.
What is the tested interrupt current rating for these reducers?
Mersen Fuse Reducers have been tested to 200,000A.
Can Class J Fuse Reducers be used for bolt-on applications?
No, Class J Fuse Reducers are not intended for bolt-on applications.
What is the function of the R166 Fuse Reducer?
The R166 Fuse Reducer allows a 60A fuse to fit into 100A clips for Class R applications.
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.


