Authorized Mersen Distributor
Mersen M331142 - Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 2-Pole Visual Indicator 2c.x Microswitch Pressure Plate IP20

Mersen M331142 Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 2-Pole Visual Indicator 2c.x…

Alternate Item Number: US142M2I

UPC: 782001311018


Documents & Media
Specification Sheet

Contact for Pricing

Minimum Qty: 3

Multiplier: 3

*Contact for lower quantities*

Call +1 (262) 252-1600 (toll-free 877-268-3700) or email [email protected] for pricing and availability.

Overview

The Mersen UltraSafe US14 2-pole fuse holder (SKU: M331142) delivers robust overcurrent protection for industrial power systems with a 50A continuous current rating and 200kA SCCR. Designed for 800VAC/1000VDC applications, this finger-safe fuse holder supports Mersen A70QS, A70P, URC, and URD fuse sizes (14x51) while providing IP20 protection against accidental contact. Key features include a visual blown-fuse indicator for immediate fault detection and an optional microswitch for remote monitoring of fuse status. The 2-pole design enables series or parallel configurations, with field-configurable multi-pole assemblies via pin-tie kits. Padlocking capabilities enhance operational safety during maintenance. Applications include protection for sensitive equipment such as small inverters, UPS systems, motor drives, and semiconductor circuits. The compact design measures 97.5mm (with MC2R 3E) and integrates striker mechanisms visible after fuse operation for clear status indication. Terminals are type TTF with M8 threading for secure connections. Compatible with Mersen’s semiconductor protection fuse series, this fuse holder ensures reliable fault isolation in high-energy DC and AC systems.
  • 2-pole design for 50A continuous current and 200kA SCCR
  • 800VAC/1000VDC rated with IP20 finger-safe protection
  • Visual blown-fuse indicator and optional microswitch for remote monitoring
  • Supports Mersen A70QS, A70P, URC, URD fuse sizes (14x51)
  • Field-configurable multi-pole assemblies with pin-tie kits and padlocking

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
Connection Type
Microswitch, Pressure Plate
Connection Type
Screw Terminal
Current Rating
50A
Current Rating
50 A
DC Voltage Rating
1000 V
IP Rating
IP20
Material
thermoplastic or thermoset
Material
Polyamide
Material
Thermoplastic / Thermoset
Maximum Operating Temperature
60 C
Minimum Operating Temperature
-25 C
Mounting
DIN rail acc. EN 60715
Mounting Type
DIN Rail
Number of poles
2
Operating Temperature, Maximum
140 F
Operating Temperature, Minimum
-13 F
Phase
2
Poles
2
Series
UltraSafe™ US14
Series
UltraSafe™
Series
UltraSafe US14
Size
14X51
Size
3.01 x 2.09 x 4.36;76.5 x 53 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
Voltage Rating
800 VAC / 1000 VDC
Voltage Rating
800VAC, 1000VDC
Package Dimensions (L x W x H)
3.01 in x 2.09 in x 4.36 in
Package Dimensions (L x W x H)
76.5 mm x 53 mm x 110.8 mm
Package Weight (Imperial)
0.683 lb
Package Weight (Metric)
0.310 kg
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 2-Pole Pressure Plate IP20

G331137

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 2-Pole Pressure Plate IP20
10x38mm CYLINDRICAL FUSEHOLDER 81A ID. The CYH Series fuse holders are designed to hold cylindrical 10x38, 14x51 and 22x58 mm fuses. The CYH series features a compact IP20 touch-safe design for maximum space savings and safety. Features/Benefits: Compact design IP20 Finger-Safe Design. 35 mm DIN Rail Mountable. Made of a polymer high performance with a fusion temperature more than 300 °C. This provides a safety margin against a possible overheating of the fuse.

CYH10381ID

10x38mm CYLINDRICAL FUSEHOLDER 81A ID. The CYH Series fuse holders are designed to hold cylindrical 10x38, 14x51 and 22x58 mm fuses. The CYH series features a compact IP20 touch-safe design for maximum space savings and safety. Features/Benefits: Compact design IP20 Finger-Safe Design. 35 mm DIN Rail Mountable. Made of a polymer high performance with a fusion temperature more than 300 °C. This provides a safety margin against a possible overheating of the fuse.
Modular fuse holder 2P 600V with LED

57050012

Modular fuse holder 2P 600V with LED
E 90 50/125 fuse holders are appropriate to protect against overloads and short circuits. They are designed for use with cylindrical fuses from 50 to 125 A.

E91N/125

E 90 50/125 fuse holders are appropriate to protect against overloads and short circuits. They are designed for use with cylindrical fuses from 50 to 125 A.
Terminal Covers (2 Covers Per Kit). Field installed primary and secondary IEC Touch Proof Cover Kit.

IP20

Terminal Covers (2 Covers Per Kit). Field installed primary and secondary IEC Touch Proof Cover Kit.
Fuse holder FEC

18813000019

Fuse holder FEC
Control Transformer Accessories - Secondary Fuse Kit 3

SFK3

Control Transformer Accessories - Secondary Fuse Kit 3
Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 22x58 3-Pole Visual Indicator Microswitch Pressure Plate IP20

V331172

Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 22x58 3-Pole Visual Indicator Microswitch Pressure Plate IP20

Frequently Asked Questions

What are the UL ratings for the UltraSafe™ US14 fuse holders?

The UL ratings for AC are 800 VAC, 50 A, 50 kA, and for DC are 1000 VDC, 50 A, 50 kA.

What fuse link size is compatible with the UltraSafe™ US14?

The UltraSafe™ US14 is designed for cylindrical fuse links of size 14x51.

What is the operating temperature range for the UltraSafe™ US14?

The operating temperature range for the UltraSafe™ US14 is -25°C to 60°C.

What is the degree of protection for UltraSafe™ fuse-holders?

The UltraSafe™ modular fuse-holders are finger-safe under IEC standards with an IP20 grade of protection.

What is the storage temperature range for the UltraSafe™ US14?

The storage temperature range for the UltraSafe™ US14 is -25°C to 80°C.

What wire sizes can be connected to the fuse holders?

Rigid wire connections can be from 1.5-35mm² (16-3AWG), and stranded wire connections can be from 1.5-25mm² (16-4AWG).

What types of circuits can the UltraSafe™ US14 be used for?

The UltraSafe™ US14 can be used for all circuits up to 750VAC for protection of motors, transformers, low voltage distribution, and control circuits.

What is the voltage limit for the blown fuse indicator?

The voltage limit for the blown fuse indicator is 230 to 690V AC/DC.

What is the maximum tightening torque for wire connections?

The maximum tightening torque for wire connections is 3.5 Nm (30 lbs-in).

What is the SCCR rating for the UltraSafe™ US14?

The Short-Circuit Current Rating (SCCR) for the UltraSafe™ US14 is 100 kA.

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.