Mersen A2D-R Class RK1 Time-De...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$103.46
Mersen A2D-R Class RK1 Time-Delay Fuse, 250VAC/250VDC, Blade, SmartSpot Indication

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

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Model: A2D70R

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

$103.46
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Mersen A2D400R Class RK1 400A Time-Delay Fuse with SmartSpot Indication

The Mersen A2D400R is a Class RK1 time-delay fuse rated 400A at 250VAC/250VDC, engineered for reliable overcurrent protection in demanding industrial and commercial electrical systems. Built with PolyTube insulating material and tin-plated copper blade terminals, it delivers a 200 kA breaking capacity along with SmartSpot indication technology for fast visual status verification. Its dual AC/DC voltage rating and clip mounting make it a versatile, professional-grade choice for coordinated circuit protection.

Key Features

  • Ampere Rating: 400A rating supports high-amperage loads with dependable overcurrent protection.
  • Fuse Class: Class RK1 performance provides superior current-limiting characteristics and coordination with downstream protective devices.
  • Speed Characteristic: Time-delay operation allows temporary overloads while responding quickly to fault conditions, suited to motor and transformer applications.
  • Breaking Capacity: 200 kA AC max breaking capacity delivers exceptional fault current interruption capability.
  • Dual Voltage Rating: Rated 250VAC and 250VDC (50/60 Hz) for versatile use across AC and DC electrical configurations.
  • Indication System: SmartSpot indication enables quick visual identification of fuse status, reducing troubleshooting time.
  • Connection Terminal: Tin-plated copper blade terminals with clip mounting ensure secure, corrosion-resistant electrical contact.
  • Body Insulating Material: PolyTube construction supports long-term durability.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Indication System: Yes
  • Indication System Type: SmartSpot®
  • Rohs Compliant: Yes
  • Ac Max I R Breaking Capacity I1: 200 kA
  • Ac Or Dc: AC/DC
  • Ampere Rating: 400 A
  • Body Insulating Material: PolyTube
  • Connection Terminal Material: Tin-Plated Copper
  • Connection Terminal Type: Blade
  • Frequency Hz: 50/60 Hz
  • Fuse Class: Class RK1
  • Mounting Method: Clip
  • Product Length: 8.63 in
  • Product Weight: 1.64 lb
  • Rated Voltage Ac Ul: 250 V
  • Rated Voltage Dc Ul: 250 V
  • Speed Characteristic: Time Delay

Typical Applications

  • Industrial Motor Control Centers
  • Commercial Power Distribution Systems
  • Manufacturing Equipment Protection
  • HVAC System Circuit Protection
  • Data Center Power Infrastructure
  • Process Control Equipment

Why Mersen?

Mersen fuses combine RoHS-compliant, professional-grade construction with proven reliability for coordinated circuit protection. The PolyTube insulating body and tin-plated copper blade terminals support long-term performance, while SmartSpot indication adds operational visibility that helps maintenance teams verify fuse status quickly during professional electrical work.

Manufacturer Resources

Product Specs

Connection Type:
Blade
Product Type:
Time-Delay Fuse
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuses

Mersen A2D70R – Frequently Asked Questions

1) Will a Mersen A2D-R fuse drop into an existing Class RK5 or Class H fuse holder?
The A2D-R is a Class RK1 time-delay fuse with blade terminals and clip mounting, so it uses the standard rejection-style Class R mounting. It fits Class R rejection clips and also non-rejection Class H/K clips of the same amp range, but a Class R rejection clip will not accept a plain Class H or K fuse in reverse. Upgrading from RK5 to RK1 in the same holder is a common move because RK1 is more current-limiting, which lowers the let-through energy your downstream gear sees.
2) Can I use the A2D-R on a 480V motor circuit?
No. The A2D-R is rated 250V AC and 250V DC, so it is limited to 240V-class systems (208/240V three phase, 120/240V single phase, and DC up to 250V). For a 480V feeder or motor circuit you need a 600V Class RK1 fuse instead, not this one.
3) Will a time-delay fuse hold up to motor inrush without nuisance blowing?
That is what it is built for. The A2D-R has a time-delay characteristic, so it rides through the temporary overload of motor starting or transformer magnetizing inrush while still clearing a genuine fault fast. On a fast-acting fuse of the same amp rating you would see nuisance openings on every start. For non-motor resistive or lighting loads, a fast-acting fuse is the usual choice.
4) Is the interrupting rating enough for a service with high available fault current?
The A2D-R carries a 200 kA AC maximum breaking capacity, which covers essentially any commercial or industrial service point you will encounter, and as a Class RK1 fuse it is current-limiting, so it can be used to build a series-rated or fully-rated protection scheme ahead of gear with a lower withstand.
5) Is a Littelfuse CCMR040 an acceptable substitute for a 70A Mersen A2D-R time-delay fuse?
No. The Littelfuse CCMR040 is a Class CC time-delay fuse rated 40 amps, so it neither matches the 70A rating of the A2D70R nor the Class RK1 body and blade-terminal clip mounting the A2D-R series uses. Class CC fuses are ferrule-style midget fuses that seat in dedicated Class CC holders, while the Mersen A2D-R mounts in R-class fuse clips. Use the CCMR040 only where the drawing calls for a 40A Class CC device; for a 70A Class RK1 slot, stay with the A2D70R.
6) Which amp ratings does the Mersen A2D-R time-delay fuse come in?
Two ratings are offered: 70A (A2D70R) and 400A (A2D400R). Both are Class RK1 time-delay, 250VAC/250VDC. Pick the amp rating against your motor or transformer load and the holder it sits in, since the fuse body and blade size change with amperage.
7) How do maintenance techs tell if the fuse has opened without pulling it?
The fuse carries Mersen SmartSpot indication, a visual indicator on the fuse body that shows whether it has operated. A tech can check status at the disconnect by eye instead of pulling each fuse and ohming it out, which is the difference between a two-minute check and a shutdown on a three-phase set.
8) Can this fuse be used on a DC circuit, like a battery or drive bus?
Yes, it is dual rated AC/DC at 250V on both, with an AC frequency rating of 50/60 Hz. That makes it usable on DC buses up to 250V as well as 240V-class AC, which is not true of every Class RK1 fuse.
9) Is there a smaller time-delay fuse for control circuits instead of an RK1?
For branch and control circuits an RK1 blade fuse is oversized. A Class CC time-delay fuse is the right form factor there, and ZenSupply carries the Littelfuse CCMR040, a CCMR Series Class CC time-delay fuse at 40A. Class CC is rejection-mounted in small fuse blocks and is the usual pick for motor control transformer primaries and starter control power, while the A2D-R belongs on the feeder or motor branch.
10) Is a midget or glass tube fuse an acceptable substitute for an A2D-R?
No. A midget fuse such as the Littelfuse BLF Series (250V, fast-acting, laminated tube) and glass tube fuses like the Littelfuse AGA or AGU Series are small ferrule or clip-in fuses for control, electronic, and automotive style circuits. They are not Class R, will not fit RK1 blade clips, and do not give you the RK1 current-limiting performance or the 200 kA breaking capacity the A2D-R does.
11) What is the difference between the Mersen A2D-R and Littelfuse AGA or AGU glass fuses?
They serve different parts of a system. The Littelfuse AGA5 is a 5A glass fuse and the AGU series is an AG glass tube fuse, both small glass-body fuses used for low-current circuits and equipment protection. The Mersen A2D-R is a Class RK1 time-delay power fuse offered in 70A and 400A ratings at 250VAC/250VDC with a PolyTube body, tin-plated copper blade terminals, 200 kA AC breaking capacity and SmartSpot indication for branch and feeder protection. A glass fuse is not a substitute in an R-class fused switch or motor control center.
12) Are the terminals corrosion resistant for a humid or outdoor enclosure?
The blade terminals are tin-plated copper, which resists oxidation at the clip contact and keeps contact resistance down over time. The body is PolyTube insulating material, and the fuse is RoHS compliant.
13) Can I use a Square D PowerLogic energy meter fuse pack instead of a Mersen A2D-R fuse?
No. The Square D PowerLogic fuse pack is a set of three 0.5A 600V fuses intended for metering circuits, where the fuse protects the voltage sensing leads of an energy meter. The Mersen A2D-R is a 250VAC/250VDC Class RK1 time-delay power fuse in 70A and 400A ratings with blade terminals and clip mounting, used for load and feeder protection. The two are not interchangeable in either direction.
How fast can I get the Mersen A2D70R 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 A2D70R come with a warranty?
Absolutely. The Mersen A2D70R 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 A2D70R?
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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