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Mersen K331140 - Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 2-Pole Visual Indicator Microswitch Pressure Plate IP20

Mersen K331140 Fuse Holder UltraSafe™ 800VAC 1000VDC UL Fuse size 14x51 2-Pole Visual Indicator…

Alternate Item Number: US142MI

UPC: 782001310998


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Specification Sheet

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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 K331140 is a 2-pole UltraSafe™ modular fuse holder engineered for 14x51mm fuse links, delivering robust circuit protection up to 800VAC/1000VDC. The microswitch can be supplied pre-installed or ordered separately for field installation, enabling seamless integration into control and monitoring systems. Its Short Circuit Current Rating (SCCR) reaches 200kA, ensuring reliable performance under fault conditions. The modular design allows field assembly into multi-pole units using pin-tie kits, while a unique DIN rail mounting system with latching capability simplifies installation and repositioning. Padlocking features enhance operational security. The holder is compatible with Mersen’s A70QS, A70P, URC, and URD fuse links. Dimensions: 34.6mm width, 77.4mm depth, 48mm height. Weight: 48g. Designed for environments requiring reliable, high-integrity fuse protection with remote monitoring capabilities.
  • 2-pole modular design for 14x51mm fuse links (A70QS, A70P, URC, URD compatible)
  • 800VAC/1000VDC rating with 50A max current and 200kA SCCR
  • IP20 finger-safe enclosure with visual blown-fuse indicator and microswitch
  • DIN rail mounting with latching system and padlocking capability
  • Durable thermoplastic/thermoset construction, flame retardant (UL94V2)

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
Screw Terminal
Current Rating
50 A
DC Voltage Rating
1000 V
IP Rating
IP20
Material
Polyamide
Material
Thermoplastic/Thermoset (UL94V2)
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-Pole
Series
UltraSafe
Size
14x51 mm
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
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
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Frequently Asked Questions

What is the degree of protection for these fuse-holders?

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

What are the UL ratings for AC and DC voltage and current?

The UL ratings are 800 VAC at 50 A and 50 kA, and 1000 VDC at 50 A and 50 kA.

What is the operating temperature range for the UltraSafe™ US14 fuse-holders?

The operating temperature range is from -25°C to 60°C.

What is the maximum tightening torque for the connections?

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

What wire sizes can be connected to the fuse-holders?

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

What fuse link size is compatible with the US14 series?

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

Can these fuse-holders be mounted on DIN rails?

Yes, the fuse-holders are designed for installation on DIN rails to EN 60715.

What is the purpose of the optional microswitch?

The optional microswitch allows for remote indication and can signal fuse melting or pre-isolation before main contact opening.

What are the current ratings for the auxiliary microswitch?

The auxiliary microswitch has utilization category AC15 ratings of 4A/24V to 2.5A/240V and DC13 ratings of 3A/24V to 0.1A/240V.

Can multi-pole units be assembled in the field?

Yes, multi-pole units can be field assembled by ordering a pin-ties assembly kit.

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.