Mersen A4BQ Class L Time-Delay...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$1,867.63
Mersen A4BQ Class L Time-Delay Fuse

Mersen A4BQ Class L Time-Delay Fuse

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Model: A4BQ800

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

$1,867.63
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Mersen A4BQ600 Class L Time-Delay Fuse, 600A 600VAC/500VDC

The Mersen A4BQ600 Class L Time-Delay Fuse is part of the Amp-Trap 2000 series, delivering high-interrupting-capacity overcurrent protection for demanding power systems. Rated 600A with dual voltage capability of 600VAC/500VDC, this fuse features blade terminal connections, silver-plated copper conductors, and a GMG insulating body, backed by a 200 kA interrupting capacity for reliable fault protection in critical electrical installations.

Key Features

  • 600A Ampere Rating: Provides dependable overcurrent protection for heavy-duty electrical systems and high-current circuits.
  • Dual Voltage Capability (600VAC/500VDC): Supports both AC and DC circuit configurations for versatile power system protection.
  • 200 kA Interrupting Capacity: Delivers exceptional fault current interruption for safe operation under extreme fault conditions.
  • Time-Delay Speed Characteristic: Allows brief inrush and overload conditions while responding quickly to sustained faults, suited to motor and transformer circuits.
  • Blade Terminal Connection: Silver-plated copper terminals ensure superior conductivity and corrosion-resistant, long-term electrical connections.
  • Class L Design with Bolted Mounting: Meets stringent safety requirements for high-capacity fuse applications with a secure bolted mounting method.
  • GMG Body Insulating Material: Provides durable, non-conductive housing for consistent performance in demanding environments.
  • RoHS Compliant Construction: Environmentally responsible design meets current regulatory requirements for electrical components.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Body Insulating Material: GMG
  • Rohs Compliant: Yes
  • Fuse Class: Class L
  • Ampere Rating: 600 A
  • Rated Voltage AC UL: 600 V
  • Rated Voltage DC UL: 500 V
  • AC Max I R Breaking Capacity I1: 200 kA
  • Connection Terminal Material: Silver-Plated Copper
  • Connection Terminal Type: Blade
  • Mounting Method: Bolted
  • Speed Characteristic: Time Delay
  • Frequency: 50/60 Hz
  • Product Length: 8.63 in
  • Product Weight: 2.44 lb

Typical Applications

  • Industrial Motor Protection Systems
  • Commercial Power Distribution Panels
  • Heavy-Duty Transformer Protection
  • Manufacturing Equipment Overcurrent Protection
  • Data Center Power Infrastructure
  • Hospital and Critical Facility Electrical Systems

Why Mersen?

Mersen engineers the Amp-Trap 2000 series to deliver dependable, code-compliant overcurrent protection for critical power infrastructure. With silver-plated copper terminals, a GMG insulating body, and RoHS compliant construction, the A4BQ600 Class L fuse is built for long-term reliability in demanding industrial and commercial electrical environments.

Manufacturer Resources

Product Specs

Product Group:
Wiring Devices
Series:
Amp-Trap 2000
Product Type:
Fuse
Product Material:
GMG
Standards:
RoHS Compliant
Voltage Rating:
600VAC/500VDC
Department:
Electrical
Connection Type:
Blade

Mersen A4BQ800 – Frequently Asked Questions

1) What amp ratings does the Mersen A4BQ Class L fuse come in?
Two ratings are offered in the A4BQ Amp-Trap 2000 Class L line: 600A as part number A4BQ600, and 800A as A4BQ800. Both are ordered by that part number, so specify the amperage that matches your service or feeder overcurrent calculation.
2) Can I use the Mersen A4BQ fuse on a DC circuit?
Yes. The A4BQ carries a dual rating of 600VAC and 500VDC, so it works on AC distribution and on DC systems up to 500 volts. On AC it is rated for 50/60 Hz service.
3) Will a Class L fuse like the A4BQ drop into a fuse clip holder?
No. Class L fuses are bolt-in only. The A4BQ uses blade terminals with a bolted mounting method, so it lands on a bolted fuse block or switch bus, not spring clips. If your gear takes a ferrule or knife-blade clip fuse, this is the wrong class entirely.
4) Is the A4BQ time-delay or fast-acting, and does that matter for a motor feeder?
Time delay. The A4BQ rides through brief motor inrush and transformer magnetizing current while still clearing sustained faults, which is why it suits motor circuits and transformer primaries. If your load is purely electronic or you need the fastest possible let-through for semiconductor protection, a time-delay Class L is not the right choice.
5) What fault current can the Mersen A4BQ interrupt?
200 kA at its rated voltage. That covers the available fault current at most large service entrances and switchboard mains, which is the usual reason a Class L fuse gets specified over a lower-rated device.
6) Can a Littelfuse CCMR Class CC fuse be used in place of a Mersen A4BQ Class L fuse?
No. The Mersen A4BQ is a Class L time-delay fuse with blade terminals and a bolted mounting method, covering 600A and 800A ratings at 600VAC/500VDC. The Littelfuse CCMR040 is a Class CC time-delay fuse rated 40A, a small ferrule-style branch-circuit fuse that seats in a clip or Class CC holder. The two are different fuse classes with different physical mountings and two orders of magnitude apart in ampere rating, so neither fits the other's fuseholder. Use the CCMR for small motor-control and branch loads, and the A4BQ where a bolted Class L fuse protects a main or feeder.
7) For metering and instrumentation circuits, should I use a Mersen A4BQ or a Square D PowerLogic fuse pack?
Use the Square D PowerLogic Energy Meter Fuse Pack, which is a set of three 0.5A 600V fuses intended to protect the voltage-sensing leads of an energy meter. The Mersen A4BQ is a 600A or 800A Class L time-delay fuse with bolted blade terminals sized for main and feeder overcurrent protection at 600VAC/500VDC. Both are 600V-class devices, but the metering fuse pack handles the milliamp-level sensing circuit while the A4BQ handles the power circuit feeding the switchboard.
8) I need a time-delay fuse but my holder is a 30A branch circuit, not a Class L bolted block. What should I look at?
A Class L device like the A4BQ starts at 600A and bolts in, so it does not apply to a small branch circuit. For a 40A time-delay branch application, the Littelfuse CCMR040 is a Class CC time-delay fuse that fits a rejection-style CC holder. For small glass-tube work, Littelfuse offers the AGA and AGU series instead.
9) Is a midget fast-acting fuse an acceptable substitute for the A4BQ?
No. The Littelfuse BLF series is a 250V midget fast-acting fuse, a completely different class, voltage, and mounting style. Nothing in the midget or glass-tube families substitutes for a 600V bolted Class L fuse on a main or large feeder.
10) What is the difference between a time-delay fuse like the Mersen A4BQ and a fast-acting fuse like the Littelfuse BLF midget?
The Mersen A4BQ has a time-delay speed characteristic, so it rides through the brief inrush of motor starting and transformer magnetizing current while still clearing sustained faults, and it carries a 200 kA interrupting rating at 600VAC/500VDC. The Littelfuse BLF is a fast-acting midget fuse rated 250V in a laminated tube, which opens quickly on overcurrent and suits control circuits and electronics that cannot tolerate let-through energy. Choose the A4BQ where inrush is expected on a 600V system, and a fast-acting midget where a load needs to be cleared promptly at 250V.
11) Is a Littelfuse AGU or AGA glass tube fuse an alternative to the Mersen A4BQ?
No. The Littelfuse AGA5 is a 5A glass fuse and the AGU is a glass tube fuse, both small cartridge fuses used in low-current automotive, appliance, and accessory circuits. The Mersen A4BQ is a Class L fuse in the Amp-Trap 2000 series with a GMG insulating body, silver-plated copper blade terminals, and bolted mounting, offered at 600A and 800A on 600VAC/500VDC systems. Glass tube fuses are not rated or built for feeder-level fault duty and cannot substitute for a bolted Class L fuse.
12) What are the terminals and body made of on the Mersen Amp-Trap 2000 A4BQ?
Terminals are silver-plated copper, which keeps contact resistance low and resists corrosion at a bolted joint that may sit for years. The body is GMG insulating material. The fuse is RoHS compliant.
13) Where is a 600A or 800A Class L fuse typically used in a building?
Service entrance and switchboard mains, large feeders, heavy transformer primaries, industrial motor protection, and data center or hospital power infrastructure. Essentially anywhere the circuit exceeds what Class J or Class RK can cover and the available fault current is high.
How fast can I get the Mersen A4BQ800 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 A4BQ800 come with a warranty?
Absolutely. The Mersen A4BQ800 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 A4BQ800?
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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