Mersen Amp-Trap® A2K Series Fa...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$49.19
Mersen Amp-Trap® A2K Series Fast-Acting Class RK1 Fuse, 250V

Mersen Amp-Trap® A2K Series Fast-Acting Class RK1 Fuse, 250V

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Model: A2K1R

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

$49.19
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Mersen Amp-Trap® A2K Series Fast-Acting Class RK1 Fuse, 250V

The Mersen Amp-Trap® A2K Series is a current-limiting Class RK1 fuse engineered for branch/feeder circuits and back-up protection where high available short-circuit currents exist. Rated 250V AC/DC with a fast-acting speed characteristic and an AC maximum interrupting rating of 200 kA, this rejection-style fuse mounts via clip with ferrule-type, tin-plated copper terminals. Its fiberglass (GMG) body delivers dimensional stability in harsh industrial environments, and the design is UL Listed and CSA Certified for demanding commercial and industrial power distribution applications.

Key Features

  • Ampere Rating: 1 A for precise overcurrent protection in low-amperage branch and feeder circuits.
  • Rejection-Style Design: Prevents replacement by other fuse classes, preserving system coordination and safety.
  • High Current Limitation: Delivers low peak let-through current for excellent protection against high available short-circuit currents.
  • Durable Construction: Fiberglass (GMG) body provides dimensional stability in harsh industrial environments.
  • Connection/Terminal Type: Ferrule terminals with tin-plated copper construction for reliable, corrosion-resistant connections.
  • Mounting: Clip-mount configuration for straightforward installation and replacement.
  • Easy-to-Read Imprint Label: Speeds recognition and replacement in the field.
  • AC Max Interrupting Rating: 200 kA for dependable performance under high fault-current conditions.

Certifications & Compliance

  • UL Listed to standard 248-12, File E2137
  • CSA Certified to standard C22.2 No. 248.12
  • Self-certified for DC per UL248

Technical Specifications

  • Ampere Rating: 1 A
  • Body/Insulating Material: GMG
  • Rated Voltage AC UL: 250 V
  • Rated Voltage DC UL: 250 V
  • Speed/Characteristic: Fast-Acting
  • Fuse Class: Class RK1
  • Connection/Terminal Type: Ferrule
  • Connection/Terminal Material: Tin-Plated Copper
  • AC Max I.R./Breaking Capacity: 200 kA
  • Mounting: Clip

Typical Applications

  • Non-Inductive Loads
  • Load Centers and Switchboards
  • Panelboards
  • Feeder Circuits
  • Bus Duct
  • Lighting Circuits

Why Mersen?

Mersen's Amp-Trap® A2K Series combines a rejection-style Class RK1 design with a rugged fiberglass body to deliver current-limiting, code-compliant overcurrent protection for demanding electrical systems. Backed by UL Listing and CSA Certification, these fast-acting fuses give electrical professionals a dependable, easy-to-identify solution for branch/feeder and back-up protection.

Manufacturer Resources

Mersen Product Catalog

Product Specs

list_batch:
MERSEN-20260825
Product Type:
Fast-Acting Fuse
Product Material:
Fiberglass
Voltage Rating:
250V
Amperage Rating:
1A
Connection Type:
Ferrule
Listing:
UL Listed
Series:
A2K Series
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuses

Mersen A2K1R – Frequently Asked Questions

1) Will a Mersen A2K1R Class RK1 fuse fit my existing Class R rejection fuse clips?
Yes. The A2K1R is a rejection-style Class RK1 ferrule fuse with a clip mount, so it drops into Class R rejection clips sized for a 250V Class R fuse. The rejection feature is one-way: a Class R fuse will seat in standard non-rejection clips too, but a non-rejection Class H or K fuse will not fit back into a Class R rejection holder. That is the point of the design, it keeps the circuit from being downgraded at the next replacement.
2) Can I use the Mersen A2K1R on a 480V circuit?
No. The A2K series fuse is rated 250V, AC and DC, and must not be applied above that. For a 480V or 600V feeder you need a 600V class fuse instead. Within its rating it carries a 200 kA AC interrupting rating, which is what makes it suitable where available short-circuit current is high.
3) What should I use instead of the Mersen A2K1R if the load is a motor circuit that inrushes on start?
The A2K Series is a fast-acting Class RK1 fuse intended for non-inductive loads, feeder circuits, panelboards and lighting circuits, so it is not the right choice where a motor draws heavy starting current. For that duty, a time-delay fuse such as the Littelfuse CCMR Series Class CC time-delay fuse is the appropriate type; the CCMR040 is the 40A rating in that series. Note that Class CC and Class RK1 are different form factors and different holders, so the switch is a fuse block decision as well as a fuse decision.
4) Is the Littelfuse BLF a drop-in replacement for the Mersen A2K1R?
No. The Mersen A2K1R is a Class RK1 rejection-style fuse with ferrule terminals, rated 250V AC/DC and clip-mounted in RK1 rejection clips. The Littelfuse BLF is a midget fast-acting fuse rated 250V, a physically smaller body that fits midget holders rather than Class RK1 rejection clips. The two share the fast-acting speed characteristic and the 250V class, but the A2K rejection feature is specifically designed to prevent a different fuse class from being fitted in its place, so a midget fuse will not substitute in an RK1 block.
5) What does current-limiting mean for my equipment's short-circuit rating on this Mersen fuse?
The A2K clears a high fault so quickly that it holds peak let-through current and energy well below what the fault would otherwise deliver, which is how downstream gear gets protected under high available short-circuit current. It is UL Listed to 248-12 and CSA Certified to C22.2 No. 248.12, with a 200 kA AC maximum interrupting rating, and it is self-certified for DC per UL248.
6) What amp rating does the Mersen A2K1R fuse carry?
A2K1R is the 1 amp version of the A2K series, for low-amperage branch and feeder protection such as control or lighting taps. The amp value is in the part number itself, so an A2K series number reads directly as its ampere rating.
7) Can I substitute a midget or glass fuse for a Class RK1 A2K fuse?
No. Those are different physical and class families and will not coordinate the same way. A Littelfuse BLF Series midget fast-acting 250V fuse or a Littelfuse AGU or AGA glass tube fuse serves small inline and equipment-level protection, not a Class R branch or feeder disconnect. A Class R rejection holder will not accept them. Replace an A2K with another 250V Class RK1 fuse of the same ampere rating.
8) Is the Mersen A2K1R usable on a 125V or 250V DC circuit?
It is rated 250V DC as well as 250V AC, with the DC rating self-certified per UL248 rather than third-party listed. The UL Listing and CSA Certification cover the AC application to 248-12 and C22.2 No. 248.12.
9) Can I use a Littelfuse AGU or AGA glass fuse in place of the Mersen A2K1R?
No. The Littelfuse AGA Series and AGU Series are glass tube fuses, and the AGA5 is a 5A glass fuse. The Mersen A2K1R is a 1A Class RK1 fuse with a fiberglass body and tin-plated copper ferrule terminals, rated 250V AC and DC with a 200 kA AC interrupting rating for use ahead of switchboards and feeder circuits where high available short-circuit current exists. Glass tube fuses are not Class RK1 and do not fit RK1 rejection clips or carry that interrupting rating.
10) I need a 1A fuse for metering - is the Mersen A2K1R the same thing as the Square D PowerLogic meter fuse pack?
They serve different jobs. The Square D PowerLogic Energy Meter Fuse Pack is a set of three 0.5A 600V fuses supplied for metering voltage-sense leads. The Mersen A2K1R is a 1A Class RK1 branch and feeder fuse rated 250V with a 200 kA AC interrupting rating, clip-mounted on ferrule terminals. If you are fusing the potential leads of a PowerLogic meter, the 600V meter pack is the matching part; the A2K1R belongs in an RK1 block protecting a circuit.
11) Will the Mersen A2K hold up in a dusty, humid industrial panel?
The body is fiberglass (GMG), chosen for dimensional stability in harsh industrial conditions, and the ferrule terminals are tin-plated copper for corrosion resistance at the clip contact. It also carries an easy-to-read imprint label, which matters when maintenance staff are identifying a blown fuse in a crowded gear room.
12) If I want the same fast-acting response as the Mersen A2K1R but in a smaller 250V package, what are my options?
The A2K1R gives fast-acting protection at 250V in a Class RK1 rejection body. For the same speed characteristic at 250V in a compact midget size, the Littelfuse BLF Series is a midget fast-acting 250V fuse with a laminated tube body. The tradeoff is form factor and holder: the A2K is clip-mounted in RK1 rejection clips, while a midget fuse needs a midget block, so this is a panel-layout choice rather than a one-for-one swap.
How fast can I get the Mersen A2K1R delivered?
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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 A2K1R come with a warranty?
Absolutely. The Mersen A2K1R 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 A2K1R?
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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