Mersen N331143 - Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 3-Pole Pressure Plate IP20
Mersen

N331143

Alternate Item Number: US143

UPC: 782001311032

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Minimum Qty: 2

Multiplier: 2

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Overview

Mersen UltraSafe™ N331143 is a 3-pole, finger-safe fuse holder designed for 14x51mm fuses up to 50A, rated 800VAC/1000VDC. This UL-recognized component (File E52283) meets IEC standards for IP20 protection, ensuring safe fuse replacement without exposure to live parts. The modular design allows field assembly of multi-pole units using pin-tie kits, while optional microswitches (supplied or ordered separately) enable remote blown-fuse indication. The pressure plate terminal accepts wire sizes from #2 to #14 AWG (solid/stranded copper) and features a compact footprint for space-constrained panels. Approved for applications including semiconductor protection in inverters, UPS systems, and motor drives, the N331143 supports high-speed fuse types A70QS, A70P, URC, and URD. DIN-rail mounting with a unique latching system allows repositioning without tools, and padlocking capability ensures compliance with safety protocols. The thermoplastic/thermoset construction delivers durability with UL94V2 flame retardancy and a glow wire flammability index of 960°C.
  • 3-pole finger-safe fuse holder for 14x51mm fuses up to 50A
  • Rated 800VAC/1000VDC with 200kA SCCR
  • IP20 protection; safe fuse replacement without exposure to live parts
  • Modular design with optional microswitches for remote indication
  • DIN-rail mount with padlocking capability; accepts #2–#14 AWG wires

Specifications

AC Voltage Rating
800 V
Amperage Rating
50 A
Application
All circuits up to 750VAC for protection of motors, transformers, low voltage distribution, control circuits Non-load operation
Brand Name
Mersen
Class
IEC Cylindrical 14x51mm
Connection
Pressure Plate
DC Voltage Rating
1000 V
Material
Polyamide
Maximum Operating Temperature
60 C
Minimum Operating Temperature
-25 C
Mounting
DIN rail acc. EN 60715
Number Of Poles
3
Operating Temperature, Maximum
140 F
Operating Temperature, Minimum
-13 F
Phase
3
Size
3.01 x 3.13 x 4.36;76.5 x 79.5 x 110.8 in;mm
Special Features
Finger safe Degree of protection: IP20 Optional visual blown fuse indicator & microswitch DIN rail mounting Modular design Lockable Multi-pole assembly kit available Sealable in closed and open position Plastic material UL94V2 mini Flame retardant materials with glow wire flammability index to 960°C
Standard
UL Recognized Component, UL4248, guide IZLT2, file E52283 CSA Certified C22.2, class 6225, file 32169 IEC 60269-2 and IEC 60947-3 RoHS Compliant Plastic material: NF 16101 & 16102 Requirement 2 Compliant
Sub Brand
UltraSafe™
Type
UL/CSA Fuse Holders
Voltage Rating
750 VAC
Package Dimensions (L x W x H)
3.01 in x 3.13 in x 4.36 in
Package Dimensions (L x W x H)
76.5 mm x 79.5 mm x 110.8 mm
Package Weight (Imperial)
0.948 lb
Package Weight (Metric)
0.430 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.