Mersen USM4 - Fuse Holder UltraSafe™ 800VAC 1000VDC Midget 30A 4-Pole Pressure Plate IP20
Mersen

USM4

Alternate Item Number: USM4

UPC: 782001830045


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Overview

Mersen UltraSafe™ USM4 4-pole fuse holder (SKU: USM4) delivers industrial-grade protection for Midget 1-1/2" x 13/32" fuses up to 30A at 800VAC/1000VDC. Engineered for Class CC (USCC) and Midget fuse applications, this IP20-rated holder meets IEC and DIN finger-safe standards, allowing fuse changes without tools or exposure to live components. The 4-pole design with pressure plate terminals supports #14 to 6 AWG copper conductors, while the polyamide body ensures durability and exceptional insulation. Multi-pole units can be field-assembled using pin-tie handles, and optional visual blown-fuse indicators provide immediate fault detection. Snap-mounted to 35mm DIN-rail, the USM4 saves up to 15% mounting space compared to traditional solutions, reducing panel build time. Ideal for motors, control circuits, transformers, and photovoltaic systems, this UL Recognized and CSA Certified holder (File E52283) includes RoHS-compliant, lead-free materials and operates reliably from -40°C to 85°C. Compatible with ATQ, ATM, A6Y-2B, and other Midget fuses, the USM4 is a space-efficient, safety-first solution for modern electrical panels.
  • 4-pole pressure plate fuse holder for Midget 1-1/2" x 13/32" fuses up to 30A
  • Voltage rating: 800VAC / 1000VDC; IP20 finger-safe protection
  • Snap-mounted to 35mm DIN-rail; saves up to 15% mounting space
  • Optional visual blown-fuse indicators for immediate fault detection
  • UL Recognized (File E52283) and CSA Certified; RoHS-compliant polyamide body

Specifications

AC Voltage Rating
800 V
Amperage Rating
30 A
Application
All circuits up to 600 volts for motors, control circuits, transformers, etc… DC circuits up to 1000VDC including photovoltaic applications Non-load disconnect
Brand Name
Mersen
Class
Midget
Connection
Pressure Plate
DC Voltage Rating
1000 V
Material
Polyamide
Maximum Operating Temperature
80 C
Mounting
DIN Rail
Number of poles
4
Number Of Poles
4-pole
Operating Temperature, Maximum
176 F
Phase
4
Size
3.07 x 2.76 x 2.32;77.978 x 70.104 x 58.928 in;mm
Special Features
IP20 Finger-Safe (touch safe) Optional visual blown fuse Indicator lights DIN-rail mounting Compact footprint Quick, tool-free, easy fuse change outs USM use with: ATQ, ATM, A6Y-2B, A25Z-2, TRM, OTM, A13X-2, A60Q-2, DCT, HP6M, HP10M USCC use with: ATDR, ATMR, ATQR ATM, DCT, ATMR recommended for DC applications
Standard
UL Listed to Standard 4248- 4 (class CC) and UL Recognized to Standard 4248-1 (midget), File E52283 UL Listed to standard 4248-18 (photovoltaic), File E347822 CSA Certified C22.2 IEC 60269-2-1 and 60947-3 Compliant (USM only)
Sub Brand
UltraSafe™
Type
UL/CSA Fuse Holders
Voltage Rating
600 VAC
Package Dimensions (L x W x H)
3.07 in x 2.76 in x 2.32 in
Package Dimensions (L x W x H)
77.978 mm x 70.104 mm x 58.928 mm
Package Weight (Imperial)
0.560 lb
Package Weight (Metric)
0.254 kg
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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.