Mersen A4J30 Class J Fast-Acti...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$112.34
$62.34
Mersen A4J30 Class J Fast-Acting Fuse, 30A 600VAC/300VDC Ferrule Amp-Trap

Mersen A4J30 Class J Fast-Acting Fuse, 30A 600VAC/300VDC Ferrule Amp-Trap

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Model: A4J30

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

$112.34
$62.34
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Mersen A4J30 Class J Fast-Acting Fuse, 30A 600VAC/300VDC Ferrule Amp-Trap

The Mersen A4J30 Class J Fast-Acting Fuse delivers professional-grade overcurrent protection with a 30A current rating and dual voltage capability of 600VAC/300VDC. Built with ferrule terminals in tin-plated copper and a PolyTube insulating body, this Amp-Trap fuse provides 200 kA interrupting capacity and clip mounting for secure installation in commercial and industrial electrical distribution systems. RoHS compliant construction rounds out a fuse engineered for demanding overcurrent protection applications.

Key Features

  • Ampere Rating: 30A rating provides precise overcurrent protection for medium-duty electrical circuits and equipment protection applications.
  • Dual Voltage Capability: Rated 600VAC/300VDC for versatile protection across both AC and DC systems in commercial and industrial applications.
  • 200 kA Interrupting Capacity: Exceptional fault current interruption capability ensures reliable protection under severe short-circuit conditions.
  • Fast-Acting Response: Quick response time protects sensitive equipment and circuits from overcurrent damage with minimal delay.
  • Ferrule Terminal Design: Tin-plated copper terminals provide secure, corrosion-resistant connections for reliable long-term performance.
  • Class J Construction: Current-limiting design with PolyTube insulating body reduces let-through energy for superior protection versus standard fuses.
  • Clip Mounting: Clip mounting method supports secure installation in compatible fuse holders and disconnects.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Rohs Compliant: Yes

Typical Applications

  • Commercial Electrical Distribution Systems
  • Industrial Motor Control Centers
  • Power Distribution Panels
  • Equipment Protection Circuits
  • Electrical Switchgear Applications
  • DC Power Systems

Why Mersen?

Mersen delivers professional-grade overcurrent protection through the A4J30 Amp-Trap fuse, combining Class J current-limiting construction, 200 kA interrupting capacity, and dual 600VAC/300VDC voltage capability. Tin-plated copper ferrule terminals and a PolyTube insulating body support dependable long-term performance, while RoHS compliant construction meets regulatory requirements for hazardous substance restrictions. It is a dependable choice for professionals protecting critical electrical distribution and control systems.

Manufacturer Resources

Product Specs

Product Type:
Fuse
Amperage Rating:
30A
Voltage Rating:
600V AC / 300V DC
Connection Type:
Ferrule
Product Finish:
Tin-Plated Copper
Standards:
RoHS Compliant
Department:
Electrical
Product Group:
Wiring Devices

Mersen A4J30 – Frequently Asked Questions

1) Will a Mersen A4J30 fuse fit a Class J fuse block, or do I need a different holder?
The A4J30 is a Class J fuse with ferrule terminals and clip mounting, so it needs a Class J block or disconnect. Class J has its own rejection dimensions, meaning it will not seat in a Class H/K, Class R, or midget holder, and those fuses will not drop into a Class J block either. If the gear is already fused Class J at 600V, this drops straight in.
2) Can I use the Mersen A4J30 on a DC circuit?
Yes, it is dual rated at 600V AC and 300V DC, so it works in DC power systems up to 300 volts as well as 600V AC distribution. Above 300V DC it is out of rating.
3) Is 200kA interrupting rating enough for my service with a high available fault current?
200 kA is the top of the standard range for branch and feeder fuses, and the A4J30 carries it at 600V AC. Because it is a current-limiting Class J design, it also cuts let-through energy during a fault, which is what series-rating and equipment short-circuit-current-rating calculations depend on. For any commercial service where available fault current runs into the tens of thousands of amps, this rating covers it.
4) Fast-acting or time-delay for a motor circuit?
The A4J30 is fast-acting. That suits transformers only when sized for it, feeders, switchgear, and sensitive equipment protection, but a fast-acting 30A fuse will often open on motor inrush. For motor branch circuits a time-delay fuse is the right pick, such as the Littelfuse CCMR040, a Class CC time-delay rated 40A. If the gear is Class J specific, you need a time-delay Class J, not a Class CC.
5) I need fuses for a PowerLogic energy meter, not a feeder. Which one applies?
For metering, the Square D PowerLogic energy meter fuse pack is the matched item, supplied as a set of three rated 0.5A at 600V for the meter voltage inputs. The Mersen A4J30 is a 30A Class J fast-acting fuse for power circuits in distribution panels and motor control centers, so it is sized for load protection rather than a meter potential circuit.
6) Is the A4J30 a ferrule or a bolt-in fuse?
Ferrule. Class J fuses switch from ferrule to blade style as amperage climbs, and at 30A the A4J30 is the ferrule, clip-mounted version. If your block has bolt-on lugs rather than spring clips, this is not the part you want.
7) Can I swap a glass tube fuse like a Littelfuse AGU or AGA for a Mersen A4J30?
No. The AGA and AGU are small glass tube fuses for low-voltage electronics and automotive style holders, not 600V Class J gear. The A4J30 is a 600V AC industrial fuse with 200 kA interrupting capacity and Class J dimensions; nothing about the holder, voltage, or fault rating crosses over. The Littelfuse BLF is a midget fast-acting fuse rated 250V, also a different class and voltage, so it is not a substitute either.
8) What is the difference between the Mersen A4J30 and a Littelfuse BLF midget fuse?
The A4J30 is a Class J current-limiting fast-acting fuse rated 600VAC/300VDC with 200 kA interrupting capacity, intended for commercial and industrial distribution panels, motor control centers, and switchgear. The Littelfuse BLF is a midget fast-acting fuse rated 250V in a laminated tube body. Both are fast-acting, but the midget is a smaller barrel at a much lower voltage rating and does not fit Class J clips. Choose the BLF only for 250V control and supplementary circuits sized for a midget holder.
9) What is the A4J30 actually made of, and will it hold up in a damp or corrosive panel?
Terminals are tin-plated copper, which resists corrosion at the clip contact and keeps contact resistance down over time. The body is a PolyTube insulating tube rather than glass or fiber. That combination is aimed at industrial motor control centers and distribution panels rather than benign indoor electronics duty.
10) Does the Mersen A4J30 meet RoHS for our facility's procurement spec?
Yes, the A4J30 is built RoHS compliant, so it clears hazardous substance restrictions on institutional and government purchase specs. Order it by manufacturer part number A4J30.
11) I need to stock spare fuses for our panels. How many amp ratings does the A4J30 cover?
A4J30 is a single 30A fuse, one part number, one rating. Class J part numbers in this Amp-Trap family carry the amperage in the number, so a different amperage means a different number. For a stockroom, buy per rating you actually have in the gear rather than expecting one part to cover the panel.
How fast can I get the Mersen A4J30 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 A4J30 come with a warranty?
Absolutely. The Mersen A4J30 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 A4J30?
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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