Mersen Class RK1 Time-Delay Fu...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$56.93
Mersen Class RK1 Time-Delay Fuse with SmartSpot Indication, 600VAC/600VDC

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

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Model: A6D15R

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

$56.93
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Mersen Class RK1 Time-Delay Fuse with SmartSpot Indication, 600VAC/600VDC

The Mersen Class RK1 Time-Delay Fuse with SmartSpot Indication delivers dependable overcurrent protection for commercial and industrial power distribution systems, rated 600VAC/600VDC for versatile AC/DC service across the family. Built with a PolyTube insulating body and tin-plated copper ferrule terminals mounted via clip connection, these fuses pair current-limiting Class RK1 performance with high breaking capacity to protect downstream equipment during fault conditions. The integrated SmartSpot indication system gives technicians immediate visual confirmation of fuse status, cutting troubleshooting time and improving maintenance safety on critical circuits.

Key Features

  • Dual Voltage Rating: 600VAC/600VDC supports both AC and DC applications in commercial and industrial power distribution systems, rated at 50/60 Hz.
  • Class RK1 Performance: Superior current-limiting characteristics minimize let-through energy and reduce stress on downstream equipment during fault events.
  • SmartSpot Indication System: Visual indication technology instantly shows fuse status, speeding up troubleshooting and improving maintenance safety on critical circuits.
  • Time-Delay Characteristic: Rides through temporary overloads while responding quickly to sustained overcurrent conditions, well suited to motor and transformer protection.
  • Ferrule Terminal Design: Tin-plated copper terminals with clip mounting ensure secure installation and reliable electrical connections.
  • PolyTube Body Construction: Durable insulating material supports consistent performance in critical power distribution equipment.
  • High Breaking Capacity: Current-limiting design handles severe fault currents while maintaining system integrity across the family.

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Motor Control Centers and Variable Frequency Drives
  • Transformer Primary Protection
  • Commercial HVAC Systems
  • Industrial Process Equipment
  • Power Distribution Panels
  • Emergency Power Systems

Why Mersen?

Mersen fuses combine precision-engineered ferrule terminals, tin-plated copper connections, and durable PolyTube insulating construction with proven Class RK1 current-limiting performance. The integrated SmartSpot indication system adds a modern layer of visual diagnostics, helping electrical professionals maintain safe, code-compliant power distribution systems with less downtime.

Manufacturer Resources

Product Specs

Product Type:
Fuse
Product Material:
PolyTube
Connection Type:
Ferrule
Voltage Rating:
600VAC/600VDC
Department:
Electrical
Product Group:
Wiring Devices

Mersen A6D15R – Frequently Asked Questions

1) Will a Mersen A6D Class RK1 fuse fit my existing Class R fuse clips?
Class R rejection clips are what the A6D is built for. These are ferrule-terminal fuses with tin-plated copper terminals that mount by clip connection, and the RK1 class means the ferrule carries the Class R rejection feature, so it seats in a Class R rejection holder and will not drop into a non-rejecting Class H or K block. If your disconnect or MCC bucket was built for Class R fuses, the A6D goes straight in. If the existing fuses are plain Class H renewable style with no rejection ring, you need the holder converted or replaced before the RK1 will seat.
2) Can I use the Mersen A6D RK1 fuse on a DC circuit, or is it AC only?
Both. The A6D is rated 600VAC and 600VDC, so the same fuse covers a 480V or 600V AC distribution panel and a DC bus up to 600V. AC service is rated at 50/60 Hz. That dual rating is why it turns up in drive and emergency-power work where a single fuse type has to cover both sides of the equipment.
3) Why use a time-delay fuse instead of a fast-acting one on a motor circuit?
Motor inrush is the whole reason. A motor pulls several times full-load current for the first few seconds of every start, and a fast-acting fuse reads that as a fault and opens. The A6D time-delay element rides through the temporary overload and still clears a sustained overcurrent, which is what makes it the right choice for motor control centers, VFDs, transformer primaries and commercial HVAC compressors. If you are protecting a purely resistive or electronic load with no inrush, a fast-acting fuse such as the Littelfuse BLF Series midget is the type to look at instead.
4) Can I replace a Class RK5 fuse with the Mersen A6D RK1 in the same holder?
Yes, and it is a common upgrade. RK5 and RK1 share the same Class R dimensions and rejection ferrule, so an RK1 drops into any Class R holder that currently takes RK5. What changes is the let-through energy: the A6D is current-limiting with tighter RK1 characteristics, so it passes less energy to the downstream gear during a fault. Match the amp rating one for one and keep the 600V rating at or above the circuit voltage.
5) Is a Class CC time-delay fuse the same as a Class RK1 time-delay fuse for motor circuit protection?
No. The Mersen A6D is a Class RK1 time-delay fuse rated 600VAC/600VDC, offered from 10A up to 175A. The Littelfuse CCMR040 is a Class CC time-delay fuse rated 40A. Both ride through motor inrush, but Class CC and Class RK1 are different fuse classes with different body dimensions and different fuseholder and clip preps, so they are not drop-in for one another. Match the class the disconnect or motor control center is already built for: an RK1 clip will not accept a Class CC fuse, and a Class CC holder will not accept the A6D ferrule body.
6) What is the difference between a midget fast-acting fuse and the Mersen A6D time-delay fuse?
The Littelfuse BLF is a midget fast-acting fuse rated 250V in a laminated tube body. The Mersen A6D is a time-delay fuse rated 600VAC/600VDC with a PolyTube body and tin-plated copper ferrule terminals. Fast-acting means it clears quickly with no intentional delay, which suits control circuits and semiconductor-adjacent loads but will nuisance-open on motor and transformer inrush. Time-delay is the characteristic used on motor control centers, VFDs and transformer primaries. The 250V versus 600V rating also decides where each can legally be applied.
7) I need a small 600V fuse for a metering circuit, not a 100A feeder. What should I order instead?
For metering rather than feeder protection, the Square D PowerLogic Energy Meter Fuse Pack is a set of three 0.5A 600V fuses intended for energy meter voltage inputs. The Mersen A6D range starts at 10A and runs through 12A, 15A, 100A, 125A, 150A and 175A, sized for motor, transformer and distribution loads, so its smallest rating is well above what a meter potential circuit needs. Both carry a 600V rating, so the choice is amperage and application: the PowerLogic pack for the meter taps, the A6D for the circuit the meter is watching.
8) What amp ratings does the Mersen A6D RK1 time-delay fuse come in?
Seven ratings, running 10A, 12A, 15A, 100A, 125A, 150A and 175A, ordered by part number as A6D10R through A6D175R. The R suffix is the Class R rejection ferrule. If you are standardizing a panel, the low end covers control and lighting circuits and the 100A to 175A group covers feeders and larger motor branches.
9) What does SmartSpot indication actually do on a Mersen fuse?
SmartSpot is a visual status indicator built into the fuse body. Instead of pulling each fuse and ringing it out with a meter, a technician looks at the indicator and sees which one opened. On a three-phase MCC bucket or a distribution panel with a dozen fuses, that is the difference between a two-minute fault trace and twenty minutes of disconnecting and testing. It does not change the electrical rating, it changes how fast you find the blown one.
10) Is a Class CC fuse an alternative to the Mersen A6D RK1, or a different animal?
Different animal, and the holders are not interchangeable. Class CC fuses like the Littelfuse CCMR040 use a much smaller 13/32 by 1-1/2 inch body with its own rejection block, and they top out at 30A. The A6D RK1 is a Class R ferrule fuse covering 10A up to 175A at 600VAC/600VDC. If your circuit is 30A or under and you are building new with a CC block, the CCMR is a compact time-delay option. If you are feeding anything above 30A, or working in existing Class R gear, the A6D is the one that fits.
11) Can I use a 600V Mersen A6D fuse on a 240V or 480V circuit?
Yes. A fuse voltage rating is a ceiling, not a target, so a 600V fuse is correct on any circuit at or below 600V. The one thing it cannot do is go the other way, a 250V fuse on a 480V circuit will not interrupt safely. Since the A6D is rated 600VAC and 600VDC, one part number covers 208V, 240V, 480V and 600V systems, which is what makes it useful for standardizing fuse stock across a facility.
12) Can a glass tube fuse be used in place of a 600V RK1 branch circuit fuse?
No. The Littelfuse AGU and the Littelfuse AGA5 5A glass fuse are AG-series glass tube fuses, the format used for automotive, appliance and low-voltage electronics work. The Mersen A6D is a Class RK1 branch circuit fuse rated 600VAC/600VDC with a PolyTube insulating body and clip-mounted ferrule terminals for power distribution equipment. They look similar because both are cylindrical ferrule cartridges, but a glass AG fuse has neither the voltage rating nor the interrupting duty for a 600V distribution panel. Use the glass types only where the equipment specifically calls for an AG fuse.
13) Which time-delay fuse should I standardize on across a facility with mixed motor sizes?
The Mersen A6D covers 10A, 12A, 15A, 100A, 125A, 150A and 175A in one Class RK1 time-delay family at 600VAC/600VDC, with SmartSpot visual indication on each fuse so a technician can see which one opened without pulling it. The Littelfuse CCMR040 is a Class CC time-delay fuse at a single 40A rating. Standardizing on one class across a building means one set of spare stock and one clip prep; where the equipment is already fitted with Class CC holders, the CCMR is what those holders take.
14) What is the difference between the Mersen A6D and a Mersen A6K fuse?
Speed. Both are 600V Class R ferrule fuses that fit the same rejection clips, but the A6D is the time-delay version and the A6K is fast-acting. Use the A6D where inrush is part of normal operation, motors, transformers, HVAC compressors. Use a fast-acting Class R where the load is electronic or resistive and you want the quickest clearing time. Mixing them up is the usual cause of nuisance openings on a motor starter.
How fast can I get the Mersen A6D15R 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 A6D15R come with a warranty?
Absolutely. The Mersen A6D15R 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 A6D15R?
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