Mersen MD250U22 - Mersen offers a range of DC disconnect switches especially designed for PV applications, in 2 poles and 2x2 poles configurations for double circuit applications. The technology inside the switch and the visible contacts allow a quick, safe, and reliable DC breaking power at all current levels up to 1000VDC. With a symmetric 2-pole design, the product is ready and simple to install independently of the polarity, with very limited power losses, and with a smaller footprint than competition. 1000 Volts 250 Amps 2-2 configuration UL98B (PV) series.
Mersen

MD250U22

Alternate Item Number: 3605340557886

Contact for Pricing

Overview

The Mersen MD250U22 DC Disconnect Switch (SKU: MD250U22) is a UL98B-listed, PV-rated disconnect switch engineered for medium to large-scale photovoltaic (PV) solar installations up to 1000VDC. Rated for 250A continuous current, this 2-2 pole switch provides independent isolation for two separate DC circuits in a single, compact unit, ideal for string combiner boxes and inverter applications. The switch features visible contacts for immediate verification of open/closed status, enabling quick, safe, and reliable DC breaking at all current levels. Designed with a symmetric 2-pole configuration, the MD250U22 is polarity-independent, simplifying installation and reducing wiring errors. Its compact footprint saves critical space in crowded enclosures, while optimized internal design minimizes power losses for improved system efficiency. Certified to UL98B standards and compliant with NEC Article 690, the MD250U22 meets stringent safety requirements for PV applications. The switch supports both floating polarity and grounded configurations via optional jumper bars, and is rated for short-circuit currents up to 10kA. With mechanical endurance of 2000 operation cycles and an ambient operating range of -20°C to +50°C, the MD250U22 delivers long-term reliability in harsh solar environments. Compatible with standard mounting hardware and terminal shrouds (TDS250S), this UL-listed switch from Mersen ensures compliance, safety, and performance in renewable energy systems.
  • 1000VDC rated, 250A continuous current for medium/large PV systems
  • 2-2 pole configuration enables independent isolation of two DC circuits
  • Visible contacts for immediate status verification and safe DC breaking
  • Polarity-independent symmetric design simplifies installation and reduces errors
  • Compact footprint with minimal power losses compared to competitors
  • UL98B (PV) certified, compliant with NEC Article 690 for solar applications
  • Rated for short-circuit currents up to 10kA, 2000 operation cycles
  • Supports floating polarity and grounded configurations via jumper bars
  • Operating temperature: -20°C to +50°C, suitable for harsh environments

Specifications

Amperage Rating
250 A
Application
Medium and larger photovoltaic installations
Brand Name
Ferraz Shawmut
Connection
Blade Type
Mounting
Base Mounted
Number Of Poles
4
Special Features
Mersen offers a range of DC disconnect switches especially designed for PV applications, in 2 poles and 2x2 poles configurations for double circuit applications. The technology inside the switch and the visible contacts allow a quick, safe, and reliable DC breaking power at all current levels up to 1000VDC. With a symmetric 2-pole design, the product is ready and simple to install independently of the polarity, with very limited power losses, and with a smaller footprint than competition.
Standard
UL98B listed to E466972 IEC 60947-3 CE
Type
UL/CSA Switches
Voltage Rating
1000 VAC
Package Dimensions (L x W x H)
8.94 IN x 13.2 IN x 4.12 IN
Package Dimensions (L x W x H)
22.7076 cm x 33.528 cm x 10.4648 cm
Package Weight (Imperial)
5.500 L
Package Weight (Metric)
2.495 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.