Mersen A2D-R Class RK1 Time-De...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$25.66
Mersen A2D-R Class RK1 Time-Delay Fuse, 250VAC/250VDC SmartSpot Indication

Mersen A2D-R Class RK1 Time-Delay Fuse, 250VAC/250VDC SmartSpot Indication

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Model: A2D20R

In Stock (leaves warehouse same day if ordered before 3pm ET)

$25.66
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Mersen A2D-R Class RK1 Time-Delay Fuse, 250VAC/250VDC SmartSpot Indication

The Mersen A2D-R Class RK1 Time-Delay Fuse delivers reliable overcurrent protection for AC and DC circuits, rated 250VAC/250VDC at 50/60 Hz with a 20A ampere rating and 200 kA breaking capacity. Built-in SmartSpot indication gives technicians a fast visual status check during troubleshooting, while ferrule terminals in tin-plated copper resist corrosion for dependable connections. The PolyTube body and clip mounting method support secure installation in demanding industrial and commercial electrical environments.

Key Features

  • Ampere Rating: 20A for precise overcurrent protection on medium-load circuits and equipment.
  • Fuse Class: Class RK1 provides current-limiting performance and a 200 kA breaking capacity for high fault currents.
  • Speed Characteristic: Time-Delay design tolerates temporary overloads while responding quickly to short circuits and sustained overcurrent.
  • Indication System: SmartSpot indication gives a clear visual status check, reducing troubleshooting time during maintenance.
  • AC/DC Rated: Rated 250VAC/250VDC at 50/60 Hz for versatile use across AC and DC systems.
  • Connection Terminal Type: Ferrule terminals in tin-plated copper resist corrosion and ensure reliable, long-lasting connections.
  • Body Insulating Material: PolyTube body construction paired with clip mounting for secure, dependable installation.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Industrial Control Panels and Motor Control Centers
  • Commercial HVAC and Lighting Systems
  • Power Distribution Equipment and Switchgear
  • Electronic Equipment and Instrumentation Protection
  • Renewable Energy Systems and Battery Applications
  • Emergency Power and UPS Systems

Why Mersen?

Mersen backs this A2D-R Class RK1 fuse with RoHS compliant construction and SmartSpot indication technology for faster, safer maintenance checks. The durable PolyTube body and tin-plated copper ferrule terminals are engineered to deliver consistent, current-limiting circuit protection for demanding AC and DC electrical applications where reliability is essential.

Manufacturer Resources

Product Specs

Product Type:
Fuse
Series:
A2D-R
Voltage Rating:
250VAC/250VDC
Connection Type:
Ferrule
Product Finish:
Tin-Plated Copper
Standards:
RoHS Compliant
Department:
Electrical
Product Group:
Wiring Devices

Mersen A2D20R – Frequently Asked Questions

1) What amperages does the Mersen A2D-R Class RK1 fuse come in?
The A2D-R is offered in two ratings: 20A (A2D20R) and 200A (A2D200R). Both share the same 250VAC/250VDC rating, RK1 class and time-delay characteristic, so the choice comes down to the load you are protecting. The 20A sits on control and medium-load branch circuits; the 200A is a main or feeder size.
2) Can I use the Mersen A2D-R fuse on a DC circuit like a battery bank or solar array?
Yes. The A2D-R is rated 250VAC/250VDC, so it is usable on DC up to 250 volts as well as 250V AC at 50/60 Hz. That is why it shows up in battery, UPS and renewable energy work as well as standard AC panels. Above 250V DC it is the wrong fuse.
3) Will a Class RK1 fuse fit my existing Class RK5 or Class H fuse clips?
Class RK1 fuses use the standard rejection-style R dimensions, which are the same body and ferrule dimensions as Class RK5 and non-rejection Class H/K of the same voltage and amp rating. The A2D-R is a 250V ferrule-terminal, clip-mounted fuse, so it drops into existing 250V R-class clips. Going from RK5 to RK1 gets you better current limitation in the same physical space. Note the reverse is not true if the holder has rejection features cut for RK1 only.
4) Will a time-delay fuse hold on motor inrush without nuisance blowing?
That is exactly what the time-delay element in the A2D-R is for. It tolerates the temporary overload of a motor start or transformer inrush while still clearing short circuits and sustained overcurrent quickly. If you want a fast-acting fuse instead, for protecting electronics or semiconductors where no inrush tolerance is wanted, the Littelfuse BLF Series midget is a 250V fast-acting option.
5) Is the Littelfuse CCMR040 a direct replacement for a Mersen A2D-R fuse?
No. Both are time-delay fuses, but they are different classes with different bodies and mounting. The Mersen A2D-R is a Class RK1 time-delay fuse rated 250VAC/250VDC with ferrule terminals and clip mounting, while the Littelfuse CCMR040 is a Class CC time-delay fuse in the CCMR series at 40A. Class CC and Class RK1 fuses use different fuseblock and holder rejection dimensions, so a CCMR will not seat in an RK1 clip and the A2D-R will not fit a Class CC holder. Match the class stamped on the block you are pulling the fuse from.
6) When would I use a midget fast-acting fuse like the Littelfuse BLF instead of the Mersen A2D-R?
Use the midget fast-acting fuse where the load has no inrush to ride through - control transformers sized for it, electronics, and instrumentation branch circuits that need the fastest possible clearing. The Littelfuse BLF is a 250V midget fast-acting fuse in a laminated tube body. The Mersen A2D-R is a time-delay Class RK1 fuse rated 250VAC/250VDC, and the time-delay element is what lets it sit through motor starting inrush without opening, which is why it suits motor control centers and HVAC circuits. Putting a fast-acting fuse on a motor circuit sized for time-delay will nuisance-open on start.
7) Can I substitute a glass tube fuse such as the Littelfuse AGU or AGA5 for the Mersen A2D-R?
No. The AGU is an AG-series glass tube fuse and the AGA5 is a 5A glass fuse in the AGA series - small automotive and electronic-style cartridges intended for low-energy circuits. The Mersen A2D-R is a Class RK1 time-delay fuse with a PolyTube body, tin-plated copper ferrule terminals and a 200 kA breaking capacity for high fault current distribution and motor circuits. A glass body fuse has nowhere near that interrupting rating and does not fit RK1 clips. These are not interchangeable in a panel or motor control center.
8) How does SmartSpot indication help during troubleshooting?
SmartSpot is a built-in visual indicator on the fuse body, so a technician can tell an open fuse from a good one at a glance without pulling it and metering it. On a motor control center with rows of fuses that cuts the time to find the blown leg. Standard fuses without indication have to be removed and tested one by one.
9) Should I use a Class RK1 fuse or a Class CC fuse for a control panel?
Depends on the size and the holder. Class CC is a small 13/32 by 1-1/2 inch midget-style fuse used for control circuits and small motor branch protection, rated 600V, and the Littelfuse CCMR Series is the time-delay version of that class (CCMR040 is the 40A). The Mersen A2D-R is a full Class R body at 250VAC/250VDC and goes into R-class clips in disconnects, switchgear and MCCs. If your panel is wired with CC-rejection holders, an RK1 will not fit, and vice versa.
10) Can I use a glass automotive-style fuse in place of the Mersen A2D-R?
No. Glass tube fuses such as the Littelfuse AGA and AGU series are low-amperage, low-interrupting devices for accessory and electronic circuits, not a substitute for a Class RK1 branch or feeder fuse carrying a 200 kA interrupting rating at 250V. Swapping one in on a power circuit leaves the equipment unprotected against a real fault.
11) I need a fuse for a metering circuit, not a motor - is the A2D-R the right choice?
For a small metering or instrument transformer circuit, a dedicated meter fuse is the closer match. The Square D PowerLogic Energy Meter Fuse Pack is a set of three 0.5A 600V fuses built for that duty. The Mersen A2D-R is a Class RK1 time-delay fuse rated 250VAC/250VDC and is built around branch-circuit and motor-load protection, with SmartSpot indication for visual status checks. Use the A2D-R where you are protecting distribution equipment and motor loads, and the meter fuse pack where you are fusing the potential leads on a meter.
12) What is the difference between the 20A and 200A A2D-R fuses, and does the class change?
The class does not change. Both A2D20R and A2D200R are A2D-R series Class RK1 time-delay fuses rated 250VAC/250VDC with tin-plated copper ferrule terminals; only the ampere rating differs. Note that Class R fuses change physical size as the amperage band changes, so a 200A fuse will not drop into a block sized for a 20A fuse - confirm the block ampere range as well as the class before ordering.
13) Is the Mersen A2D-R RoHS compliant for a spec that requires it?
Yes, the A2D-R is RoHS compliant. That applies across both the 20A and 200A ratings.
14) What are the terminals made of, and will they hold up in a humid or corrosive plant environment?
Ferrule terminals in tin-plated copper, with a PolyTube insulating body. The tin plating is there to resist corrosion at the clip contact, which is where heat and resistance problems usually start in a damp plant or an outdoor-rated enclosure.
How fast can I get the Mersen A2D20R delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the Mersen A2D20R come with a warranty?
Absolutely. The Mersen A2D20R is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the Mersen A2D20R?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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