Mersen A2D12R - Fuse A2D-R - Class RK1 - Time-Delay 250VAC 250VDC 12A Ferrule SmartSpot® Amp-Trap 2000®
Mersen

A2D12R

Alternate Item Number: A2D12R

UPC: 782001990817


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Overview

The Mersen A2D12R is a Class RK1 time-delay fuse from the Amp-Trap 2000 series, designed to provide IEC Type 2 "no damage" protection for mains, feeders, and branch circuits. Rated for 250VAC/DC and 12 Amperes, this fuse offers a substantial 200kA interrupting rating at AC and 100kA at DC, ensuring robust protection against extreme fault conditions. Its time-delay characteristic is specifically engineered to accommodate motor in-rush currents and transformer in-rush currents without nuisance opening, making it ideal for applications involving motors, safety switches, transformers, disconnects, control panels, and general-purpose circuits. The A2D-R series features a solid-state SmartSpot® visual blown fuse indicator for quick identification of a tripped fuse (note: indicator not available on 1/10-7A ratings). These fuses are current-limiting, reducing peak let-thru current and are recommended for Arc Flash energy reduction. Their rejection-style design, when used with recommended fuse blocks, prevents improper replacements, enhancing safety and system reliability. The A2D-R fuses can effectively replace older Class H, K, or RK5 fuses, simplifying inventory and upgrading existing circuits to modern Type 2 protection standards.
  • Class RK1 Time-Delay Fuse with SmartSpot® visual indicator
  • Rated 12A, 250VAC/DC with 200kA AC / 100kA DC interrupting rating
  • Provides IEC Type 2 "no damage" protection for circuits
  • Accommodates motor and transformer in-rush currents without nuisance tripping
  • Replaces Class H, K, and RK5 fuses; recommended for Arc Flash reduction

Specifications

AC Voltage Rating
250 V
Amperage Rating
12 A
Application
Motors Safety switches Transformers Branch circuit protection Disconnects Control panels All general-purpose circuits
Body Material
PolyTube
Brand Name
Mersen
Class
Class RK1
Connection
Ferrule
Connection Material
Tin-Plated Copper
Interrupt Rating
200 kA
Mounting
Clip
Size
2 x 0.56;50.8 x 14.224 in;mm
Size
2 x 0.56 in
Size
50.8 x 14.224 mm
Special Features
Non-indicating or Solid state SmartSpot visual blown fuse indicator Time-delay for motor starting and transformer inrush currents without nuisance opening 600VAC & 600VDC dual rated 300kA interrupting rating - self-certified, UL witnessed tests Extremely current-limiting for low peak let-thru current Recommended for Arc Flash energy reduction Easy 2-to-1 selectivity for prevention of nuisance shut downs and “black outs” Rejection-style design prevents replacement errors (when used with recommended fuse blocks) High-visibility orange label gives instant brand recognition Reduced inventory by taking the place of class RK5, K, and H fuses Metal-embossed date and catalog number for easier traceability and lasting identification Fiberglass body provides dimensional stability in harsh industrial settings
Standard
UL listed to standard 248-12 File E2137 DC listed to UL standard 248 CSA certified to standard C22.2 No. 248.12
Sub Brand
Amp-Trap 2000®
Type
Class RK1
Type Of Indicators
SmartSpot®
Voltage Rating
250 VAC
Package Dimensions (L x W x H)
2 in x 0.56 in x 0.56 in
Package Dimensions (L x W x H)
50.8 mm x 14.224 mm x 14.224 mm
Package Weight (Imperial)
0.037 lb
Package Weight (Metric)
0.017 kg
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POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

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POWR-JAW clamps improve the contact between fuse and clip. The unnecessary heat from poor contact due to the loss of spring force in the clips can cause nuisance fuse opening and premature aging of surrounding components. High temperature phenolic resin knob designed for the most severe environments 7 sizes to provide effective coverage. Simple design makes installation easy.

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.