Mersen Class RK1 Time-Delay Fu...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$66.57
Mersen Class RK1 Time-Delay Fuse, 600VAC/600VDC

Mersen Class RK1 Time-Delay Fuse, 600VAC/600VDC

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Model: A6D5R

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

$66.57
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Mersen A6D50R Class RK1 Time-Delay Fuse, 50A 600VAC/600VDC

The Mersen A6D50R Class RK1 Time-Delay Fuse delivers reliable circuit protection for demanding commercial and industrial electrical applications. Engineered with a 50A ampere rating and dual 600VAC/600VDC voltage capability, this professional-grade fuse features SmartSpot indication technology for fast visual status assessment. The ferrule terminal design with tin-plated copper connections ensures secure installation and optimal conductivity in critical power distribution systems.

Key Features

  • Ampere Rating: 50A provides precise overcurrent protection for medium-duty electrical circuits and equipment loads.
  • Class RK1 Performance: Delivers superior current-limiting characteristics and enhanced safety in fault conditions.
  • Time-Delay Characteristic: Allows temporary overloads while providing fast response to fault currents, ideal for motor and inductive load protection.
  • SmartSpot Indication System: Visual indication technology enables quick status assessment and reduces troubleshooting time.
  • 600VAC/600VDC Dual Rating: Versatile AC/DC voltage compatibility supports both commercial and industrial systems, rated 50/60 Hz.
  • 200 kA Breaking Capacity: High interrupting rating ensures reliable fault current interruption in demanding electrical environments.
  • Ferrule Terminal Design: Tin-plated copper terminals provide secure clip-mount connections and excellent conductivity for professional installations.
  • Durable Construction: PolyTube body insulating material supports long service life in critical power distribution equipment.

Technical Specifications

  • Ac Max I R Breaking Capacity I1: 200 kA
  • Ac Or Dc: AC/DC
  • Ampere Rating: 50 A
  • Body Insulating Material: PolyTube
  • Connection Terminal Material: Tin-Plated Copper
  • Connection Terminal Type: Ferrule
  • Frequency Hz: 50/60 Hz
  • Fuse Class: Class RK1
  • Indication System: Yes
  • Indication System Type: SmartSpot
  • Mounting Method: Clip
  • Product Length: 5.5 in
  • Product Weight: 0.34 lb
  • Rated Voltage Ac Ul: 600 V
  • Rated Voltage Dc Ul: 600 V
  • Speed Characteristic: Time Delay

Typical Applications

  • Motor Control Centers and Industrial Equipment Protection
  • Commercial Building Electrical Distribution
  • Manufacturing and Process Control Systems
  • HVAC Equipment and Mechanical Systems
  • Power Distribution Panels and Switchgear
  • Renewable Energy and Battery Storage Systems

Why Mersen?

Mersen fuses deliver proven reliability with advanced SmartSpot indication technology and robust PolyTube construction. The 200 kA breaking capacity and Class RK1 performance ensure dependable protection in demanding electrical environments, backed by tin-plated copper ferrule terminals engineered for secure, high-conductivity connections in professional power distribution systems.

Manufacturer Resources

Product Specs

Product Group:
Wiring Devices
Product Finish:
Tin-Plated Copper
Grade:
Class RK1
Product Type:
Fuse
Voltage Rating:
600V
Department:
Electrical
Connection Type:
Ferrule

Mersen A6D5R – Frequently Asked Questions

1) Will a Mersen A6D Class RK1 fuse drop into my existing Class R fuse block?
The Mersen A6D series uses a ferrule terminal with clip mounting, which is the standard arrangement for Class R fuse blocks and rejection-style disconnects. Terminals are tin-plated copper. It carries the Class RK1 designation, so it fits a Class R rejection clip; a plain Class H or K block without rejection hardware will accept it, but an RK5 or RK1 rejection block will not accept a non-rejection fuse in return.
2) Can I use this fuse on a DC circuit, like a battery storage or solar disconnect?
Yes. The A6D is rated 600V on both AC and DC per UL, which is unusual for a general-purpose Class RK1 fuse, and Mersen lists battery storage and renewable energy systems among its applications. AC frequency rating is 50/60 Hz.
3) Why choose a time-delay RK1 instead of a fast-acting fuse for a motor circuit?
Motors draw six to eight times running current at startup, and a fast-acting fuse sized to that inrush would be too large to protect the conductors. The A6D time-delay characteristic rides through the temporary overload and still clears fault current quickly, which is why it suits motor control centers, HVAC equipment and other inductive loads. If you are protecting a non-inductive load with no inrush, a fast-acting midget fuse like the Littelfuse BLF series is the simpler choice.
4) Is a Class RK1 fuse rated for a 200,000 amp available fault current service?
Yes. The A6D has a 200 kA AC interrupting rating, which covers services fed by large utility transformers where available fault current is high. Class RK1 is also the current-limiting grade within the Class R family, so it lets through less energy under a bolted fault than an RK5 of the same amp rating.
5) Can a Littelfuse CCMR040 Class CC fuse replace a Mersen A6D50R in an RK1 fuse block?
No. The Mersen A6D50R is a Class RK1 time-delay fuse with ferrule terminals rated 600VAC/600VDC, sized at 5.5 inches long for standard R-class clips. The Littelfuse CCMR040 is a Class CC time-delay fuse rated 40A, and Class CC fuses use a much smaller midget body with a rejection feature that will not seat in an RK1 clip. Both are time-delay, so both suit motor and inductive loads, but the mounting classes are not interchangeable. If the holder is Class CC, stay with a CC fuse; if the block takes R-class ferrule fuses, the A6D50R or the 5A A6D5R is the correct family.
6) What is the difference between the Mersen A6D5R and a Littelfuse BLF midget fuse for a control circuit?
The Mersen A6D5R is the 5A member of the A6D Class RK1 time-delay family, rated 600VAC and 600VDC with a 200 kA interrupting rating and SmartSpot blown-fuse indication. The Littelfuse BLF series is a midget fast-acting fuse rated 250V in a laminated tube body. Two practical differences decide it: the BLF is fast-acting, so it will not ride through transformer or motor inrush the way the time-delay A6D5R will, and its 250V rating limits it to circuits at or below that level. For a 480V or 600V control transformer primary, the A6D5R is the one that matches the system voltage.
7) What amp ratings does the Mersen A6D time-delay fuse come in?
Two ratings are offered: 5A (A6D5R) and 50A (A6D50R). Both are the same 600VAC/600VDC Class RK1 time-delay design, so the choice is purely the load you are protecting.
8) How do I tell if a Mersen A6D fuse has blown without pulling it out of the block?
The A6D carries Mersen's SmartSpot indicator, a visual mark on the body that changes state when the element opens. You can check status with the fuse in place instead of pulling and meter-testing every leg, which is the point of it in a crowded MCC or switchgear cabinet.
9) What is the difference between this Mersen RK1 fuse and a Class CC time-delay fuse?
Size and application. The A6D is a 5.5 inch ferrule Class RK1 rated 600V AC and DC, sized for disconnects, MCCs and distribution panels. A Class CC fuse such as the Littelfuse CCMR040, a 40A CCMR series time-delay, is a much smaller 13/32 by 1-1/2 inch body used in control circuits and compact motor controllers with CC rejection holders. The two are not interchangeable in each other's blocks.
10) Is this the same thing as a glass tube fuse like an AGU or AGA?
No. Glass tube fuses such as the Littelfuse AGA5 or the AGU series are low-voltage automotive and electronics fuses. The Mersen A6D is a 600V industrial Class RK1 with a PolyTube body and a 200 kA interrupting rating, intended for branch circuit and motor protection in commercial distribution gear. Do not substitute one for the other.
11) Is a Littelfuse AGA or AGU glass fuse an alternative to the Mersen A6D5R?
They serve different circuits. The Littelfuse AGA5 is a 5A glass fuse in the AGA series and the AGU is a glass tube fuse in the AG family - small glass-body automotive and electronics-style fuses. The Mersen A6D5R is a Class RK1 time-delay power fuse with tin-plated copper ferrules and a PolyTube body, rated 600VAC/600VDC with a 200 kA breaking capacity for clip-mounted use in disconnects, panels and motor control centers. Matching on 5 amps alone is not enough; a glass AG fuse does not have the voltage rating or interrupting capacity for 600V distribution equipment.
12) My metering CT circuit needs a 600V fuse - should I order the Mersen A6D or the Square D PowerLogic fuse pack?
Use the metering pack for meter inputs. The Square D PowerLogic energy meter fuse pack is a set of three 0.5A 600V fuses intended for the voltage-sensing inputs on a PowerLogic meter. The Mersen A6D family starts at 5A and runs up to 50A in Class RK1 time-delay ferrule form, sized for feeder, motor and equipment branch protection rather than a half-amp metering tap. Both carry a 600V rating, so the deciding factor is the ampere rating the meter manufacturer calls for and the holder the leads terminate in.
13) I need a time-delay fuse for a 40A motor circuit - what are my options?
Two different mounting families cover that range. The Littelfuse CCMR040 is a 40A Class CC time-delay fuse, which requires a Class CC rejection holder. The Mersen A6D50R is a 50A Class RK1 time-delay fuse with ferrule terminals, 600VAC/600VDC, that clip-mounts into R-class fuse blocks and disconnect switches. Both are time-delay types suited to motor starting inrush. Size the fuse to the motor nameplate and the applicable overcurrent rules, then match the class to the block already in the enclosure - the two are not mechanically interchangeable.
How fast can I get the Mersen A6D5R 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 A6D5R come with a warranty?
Absolutely. The Mersen A6D5R 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 A6D5R?
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