Mersen A3T400 Class T Fast-Act...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$280.69
$241.50
Mersen A3T400 Class T Fast-Acting Fuse, 400A 300VAC/160VDC Blade Amp-Trap

Mersen A3T400 Class T Fast-Acting Fuse, 400A 300VAC/160VDC Blade Amp-Trap

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Model: A3T400

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

$280.69
$241.50
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Mersen A3T400 Class T Fast-Acting Fuse, 400A 300VAC/160VDC, Blade Amp-Trap

The Mersen A3T400 is a Class T fast-acting fuse built on Mersen's Amp-Trap blade design, rated 400A at 300VAC and 160VDC for AC/DC circuit protection. Its bolted blade terminals and GMG body insulating material support demanding industrial power distribution applications where reliable, high-speed overcurrent interruption is required. With a 200 kA AC maximum interrupting rating and 50/60 Hz frequency compatibility, the A3T400 delivers dependable current-limiting protection for panelboards, switchgear, and motor control circuits.

Key Features

  • Ampere Rating: 400A for high-capacity circuit protection in industrial power systems.
  • Voltage Rating: 300VAC / 160VDC, rated for both AC and DC applications.
  • Fast-Acting Class T Design: Rapid overcurrent response for sensitive equipment and circuit protection.
  • Blade Amp-Trap Construction: Mersen's Amp-Trap current-limiting design in a blade-terminal format.
  • Bolted Mounting: Secure bolted connection with copper connection terminal material for low-resistance contact.
  • Body Insulating Material: GMG construction for durable electrical insulation.
  • AC Max Interrupting Rating: 200 kA breaking capacity (I1) for high fault-current environments.
  • Frequency: 50/60 Hz compatibility for standard power distribution systems.

Certifications & Compliance

  • RoHS Compliant

Technical Specifications

  • Ac Max I R Breaking Capacity I1: 200 kA
  • Ac Or Dc: AC/DC
  • Ampere Rating: 400 A
  • Body Insulating Material: GMG
  • Connection Terminal Material: Copper
  • Frequency Hz: 50/60 Hz
  • Mounting Method: Bolted
  • Product Length: 2.75 in
  • Product Weight: 0.272 lb
  • Rated Voltage Ac Ul: 300 V
  • Rated Voltage Dc Ul: 160 V
  • Rohs Compliant: Yes

Typical Applications

  • Industrial Power Distribution Systems
  • Motor Circuit and Branch Circuit Protection
  • Switchgear and Panelboard Overcurrent Protection
  • AC and DC Electrical Systems Requiring High Interrupting Capacity
  • Commercial and Industrial Electrical Installations

Why Mersen?

Mersen's A3T400 combines a bolted blade Amp-Trap design with copper connection terminals and a durable GMG insulating body to deliver dependable, current-limiting fast-acting protection at 400A. Backed by a 200 kA AC maximum breaking capacity and RoHS compliance, this Class T fuse is engineered for professional electrical work where consistent, code-compliant overcurrent protection matters.

Manufacturer Resources

Mersen Product Catalog

Product Specs

Product Type:
Fast-Acting Fuse
Amperage Rating:
400A
Voltage Rating:
300VAC/160VDC
Connection Type:
Bolted
Department:
Electrical
Product Group:
Circuit Protection
Product Subgroup:
Fuses
Product Weight:
0.272 lb
Product Length:
2.75 in

Mersen A3T400 – Frequently Asked Questions

1) Does the A3T400 mount with clips or does it bolt down?
It bolts. The A3T400 uses bolted blade terminals, so it lands in a bolt-down Class T fuse block or holder, not a clip-style ferrule holder. Terminals are copper for a low-resistance connection, and the fuse body measures 2.75 in long.
2) Is a 400A Class T fuse like the A3T400 suitable for high fault-current switchgear?
Yes. The A3T400 carries a 200 kA AC maximum interrupting rating, which covers service entrance and switchgear locations with high available fault current. It is a current-limiting fast-acting design intended for panelboards, switchgear, and motor control circuits at 50/60 Hz.
3) Can a Littelfuse CCMR040 Class CC fuse be used in place of a Mersen A3T400?
No. The Mersen A3T400 is a 400A Class T fast-acting fuse with bolted blade terminals rated 300VAC/160VDC, intended for panelboard, switchgear, and motor circuit protection at high fault levels. The Littelfuse CCMR040 is a Class CC time-delay fuse rated 40A, a different class, a different ampere rating, and a rejection-style ferrule body rather than a bolted blade. The two mount in entirely different fuse holders and are not interchangeable.
4) Will a fast-acting Class T fuse hold a motor's inrush, or do I need time-delay?
The A3T400 is fast-acting, so it clears overcurrents quickly and is aimed at protecting sensitive equipment and feeders rather than riding through long motor starting inrush. Where a motor circuit needs start-up tolerance, a time-delay fuse is the right choice; the Littelfuse CCMR040 is a Class CC time-delay fuse for smaller motor branch circuits at 40A.
5) Can the A3T400 be used on a DC bus, not just AC?
Yes, it is an AC/DC rated fuse, good to 160VDC alongside its 300VAC rating. That suits battery, drive, and other DC distribution work within 160V. Above that DC level this fuse does not apply.
6) What is the exact part number and amp rating to order for a 400A Mersen Amp-Trap Class T fuse?
Order Mersen part number A3T400: a 400A Class T fast-acting Amp-Trap fuse, 300VAC/160VDC, bolted blade style. The A3 prefix is the 300V AC Class T family, and the trailing 400 is the ampere rating.
7) What is the difference between the Mersen A3T400 and a Littelfuse BLF midget fast-acting fuse?
Both are fast-acting, but they protect very different circuits. The Mersen A3T400 is a Class T fuse rated 400A at 300VAC/160VDC with bolted blade terminals and a 200 kA AC interrupting rating, sized for industrial feeders and switchgear. The Littelfuse BLF is a midget fast-acting fuse in a laminated tube rated 250V, a small clip- or holder-mounted body used for control and branch protection. If the drawing calls for a Class T bolted blade, the BLF will not fit the block.
8) I need a small fast-acting fuse for an instrument or meter circuit, not a 400A feeder. What should I look at instead of the Mersen A3T400?
The Mersen A3T400 is a 400A bolted blade Class T fuse for power distribution and will not serve a low-current instrument circuit. For metering, the Square D PowerLogic energy meter fuse pack supplies 0.5A 600V fuses as a set of three, which suits metering voltage inputs. For small glass-tube applications, Littelfuse offers the AGA series, including the AGA5 at 5A, and the AGU glass tube series.
9) Is a glass tube fuse like the Littelfuse AGU an acceptable substitute for the Mersen A3T400 in a panelboard?
No. The Littelfuse AGU is a glass tube fuse in the AG family, a small cylindrical device. The Mersen A3T400 is a 400A Class T Amp-Trap with copper bolted blade terminals, a GMG insulating body, and a 200 kA AC maximum interrupting rating for high fault-current panelboard and switchgear duty. A glass tube fuse has neither the ampere rating nor the bolted blade geometry the Class T position requires.
10) Is the Mersen A3T400 RoHS compliant for a spec that requires it?
Yes, the A3T400 is listed as RoHS compliant. The body uses GMG insulating material with copper connection terminals.
11) My circuit has inrush from a motor start. Is the A3T400 or a time-delay fuse the right choice?
The Mersen A3T400 is a fast-acting Class T fuse, which responds rapidly to overcurrent and is chosen where equipment and conductors need high-speed current-limiting protection. Where the application calls for a time-delay characteristic to ride through motor inrush, the Littelfuse CCMR040 is a Class CC time-delay fuse rated 40A. Match the characteristic and ampere rating to the circuit the engineer specified.
How fast can I get the Mersen A3T400 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 A3T400 come with a warranty?
Absolutely. The Mersen A3T400 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 A3T400?
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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