Mersen A70QS High-Speed Cylind...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$139.00
Mersen A70QS High-Speed Cylindrical Semiconductor Fuse, 700V, Ferrule Mount (22F size)

Mersen A70QS High-Speed Cylindrical Semiconductor Fuse, 700V, Ferrule Mount (22F size)

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Model: A70QS50-22F

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

$139.00
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Mersen A70QS High-Speed Ceramic Fuse, 700VDC/690VAC, Ferrule Mount, 14x51/22x58mm

The Mersen A70QS High-Speed Ceramic Fuse is engineered for critical semiconductor protection in inverters, UPS systems, solid state relays, and motor drives. Rated 700VDC and 690VAC with an ampere range of 10 to 800A, this ceramic-body fuse features dual international sizing in 14x51mm and 22x58mm with ferrule mount terminals for flexible clip-style mounting. Very low I2t characteristics and high-speed clearing minimize energy let-through during fault conditions, protecting sensitive electronic components in demanding industrial environments.

Key Features

  • Dual International Sizing: Available in 14x51mm and 22x58mm body dimensions for worldwide compatibility and acceptance.
  • Ceramic Body Construction: Delivers superior durability and thermal performance for demanding industrial environments.
  • Ferrule Mount, Clip Mounting: Ferrule terminal connections with clip mounting method provide secure connections and design versatility.
  • 700VDC / 690VAC Rating: Versatile voltage capability supports both DC and AC applications up to 750VAC in U.S. installations.
  • 10 to 800A Ampere Range: Broad current coverage suits small inverters, UPS systems, solid state relays, and motor drives.
  • Very Low I2t, High-Speed Characteristic: Rapid fault clearing and minimized energy let-through protect sensitive semiconductor components.
  • Superior Cycling Ability: Extended service life on difficult cyclic loading applications reduces maintenance requirements.
  • Interrupting Ratings: 200kA AC and 100kA DC interrupting capacity for robust fault protection.

Certifications & Compliance

  • UL Recognized Component, File E76491, JFHR2.E76491
  • CSA Certified, 1422-30
  • IEC 269-4 Compliance

Technical Specifications

  • Refer to manufacturer documentation for complete technical specifications.

Typical Applications

  • Small Inverter Protection Systems
  • UPS System Fault Protection
  • Solid State Relay Applications
  • Motor Drive Protection
  • Industrial Power Electronics
  • Renewable Energy Systems

Why Mersen?

Mersen A70QS fuses deliver proven reliability with UL Recognition, CSA Certification, and IEC 269-4 compliance for critical semiconductor protection. The ceramic body construction, high-speed characteristics, and superior cycling ability ensure dependable, code-compliant performance in demanding professional electrical installations.

Manufacturer Resources

Mersen Product Catalog

Product Specs

Product Group:
Wiring Devices
Amperage Rating:
10-800A
Configuration:
Cylindrical Non Rejection
Listing:
UL Recognized
Product Material:
Ceramic
Standards:
IEC 269-4
Voltage Rating:
700VDC
Department:
Electrical
Connection Type:
Ferrule
Product Type:
Semiconductor Fuse

Mersen A70QS50-22F – Frequently Asked Questions

1) What amperages does the Mersen A70QS 22F ferrule fuse come in?
In the 22F ferrule size, the A70QS is offered at 50A and 63A, ordered as A70QS50-22F and A70QS63-22F. The A70QS family as a whole spans 10 to 800A, but the higher currents move to larger bodies and bolt-style terminals, so if your drive calls for something above 63A you are looking at a different body size within the series, not this ferrule part.
2) Will the A70QS 22F fuse fit a standard 22x58mm fuse holder?
Yes. The 22F suffix is the 22x58mm cylindrical body with ferrule ends, which drops into clip-style holders and blocks built for that international size. The A70QS series is also made in a 14x51mm body, so confirm which size your holder takes before ordering, since the two are not interchangeable in the same clip.
3) Can I use the Mersen A70QS on a 600VDC battery or solar string circuit?
Yes, within its rating. The A70QS is rated 700VDC and 690VAC, with 200kA AC and 100kA DC interrupting capacity, and the series is used on inverter, UPS and renewable energy circuits. The description also notes support up to 750VAC in U.S. installations. Size the fuse so the circuit's maximum system voltage, including cold-temperature open-circuit rise on a PV string, stays under the DC rating.
4) Will a regular class CC or class J fuse protect my IGBT drive instead of a semiconductor fuse?
No. A branch-circuit fuse protects wiring, not silicon. The A70QS is a high-speed ceramic fuse with very low I2t, meaning it clears fast enough to hold let-through energy below what the diodes, SCRs or IGBTs can absorb. A standard-speed fuse lets through far more energy and typically clears after the semiconductor has already failed. If you are protecting a drive, inverter, UPS or solid state relay, use the semiconductor fuse.
5) Is the Mersen A70QS UL listed for a panel that needs agency-approved components?
The A70QS is a UL Recognized Component under file E76491 (JFHR2.E76491) and CSA Certified under 1422-30, and it complies with IEC 269-4. Recognized is not the same as UL Listed: it means the fuse is approved for use inside a larger listed assembly, such as a drive panel or UPS cabinet, which is exactly how these are normally applied.
6) My existing fuse has flat blade ends, not round ferrules. Will the A70QS 22F drop in?
No. The 22F is a ferrule-end cylindrical fuse meant for clip mounting, so it will not land on a bolt-down blade pattern. If your holder takes flat blade terminals, look at a blade-end semiconductor fuse such as the Bussmann FBP Series instead, or move to a larger bolted A70QS body rather than the ferrule version.
7) What is the closest cross-brand equivalent to the Mersen A70QS 700V semiconductor fuse?
The nearest peer by voltage class is the Littelfuse L70S series, a very fast-acting semiconductor fuse rated 700VAC/650VDC. The Mersen A70QS is rated 700VDC with a 690VAC rating and covers 10 to 800A across the series. Both are high-speed semiconductor protection for drives and power electronics, so confirm the ampere rating, body size, and terminal style you need before swapping, since the A70QS 22F items are ferrule-mount cylindrical bodies in a non-rejection configuration.
8) My circuit is only 500V - do I need the 700V A70QS or is there a lower-voltage semiconductor fuse?
For a 500V circuit the Littelfuse L50S series is a very fast-acting semiconductor fuse rated 500V, and the Littelfuse L25S series covers 250V applications such as the L25S030 at 250V 30A. The Mersen A70QS is built for 700VDC / 690VAC systems, so it is the choice when the DC bus or drive voltage sits in that higher class. Match the fuse voltage rating to the circuit rating and verify holder dimensions, since the A70QS 22F parts use ferrule terminals in a cylindrical non-rejection body.
9) My DC bus runs above 700V - what semiconductor fuse should I use instead of the A70QS?
The Mersen A70QS tops out at a 700VDC rating, so for a higher DC bus look at the Bussmann KAX series, which is a 1000VDC non-indicating semiconductor fuse. The Bussmann SF100X1000HP series is another semiconductor fuse option in that higher-voltage family. Keep the A70QS for 700VDC / 690VAC systems where its ferrule-mount cylindrical body fits the existing clips.
10) My fuse block uses bolt-on blade terminals - can I use the A70QS 22F?
No. The A70QS in the 22F size uses ferrule terminals with clip-style mounting, so it seats in fuse clips rather than bolting to a blade block. For a blade-end semiconductor fuse, the Bussmann FBP series is a non-indicating semiconductor fuse with blade ends. Choose by the termination your block is built for, since the two mounting styles are not interchangeable in the same holder.
11) What is the Littelfuse equivalent to a Mersen A70QS fuse?
The closest match in the comparable range is the Littelfuse L70S Series, a very fast-acting semiconductor fuse rated 700VAC/650VDC. Note the DC side: the L70S is listed at 650VDC against the A70QS at 700VDC, so on a DC bus between those two numbers the Mersen is the one that covers it. For lower-voltage circuits Littelfuse also offers the L50S at 500V, the L25S at 250V, and the L15S at 150VAC/150VDC.
12) I need more than 700VDC on my DC bus. What semiconductor fuse should I look at?
The A70QS tops out at 700VDC, so it is the wrong part for a higher bus. The Bussmann KAX Series is a 1000VDC non-indicating semiconductor fuse and covers that gap. Bussmann also offers the KAW Series and the SF100X1000HP Series in semiconductor ratings.
13) How does the Bussmann KAW series compare with the Mersen A70QS for drive protection?
Both are semiconductor fuses intended for protecting power electronics. The Bussmann KAW is a Bussmann Eaton semiconductor fuse series, while the Mersen A70QS is a ceramic-body high-speed fuse rated 700VDC and 690VAC with very low I2t and 200kA AC / 100kA DC interrupting ratings, carrying UL Recognized Component status, CSA certification, and IEC 269-4 compliance. If your panel drawing calls out an IEC 269-4 cylindrical fuse on ferrule clips, the A70QS is the form factor that matches.
14) Is a Littelfuse L15S a valid substitute for a Mersen A70QS in a 480V drive?
No. The Littelfuse L15S is a very fast-acting semiconductor fuse rated 150VAC/150VDC, well below a 480V drive circuit, so it is not a substitute for the 700VDC / 690VAC Mersen A70QS despite both being high-speed semiconductor fuses. For higher-voltage drive protection stay with the A70QS or a peer in the same voltage class such as the Littelfuse L70S at 700VAC/650VDC.
15) Will this fuse hold up on a load that cycles hard all day?
That is one of the reasons to specify it. The A70QS uses a ceramic body for thermal and mechanical durability and is built with cycling ability in mind, so it takes repeated thermal loading on difficult cyclic applications without nuisance aging the way a lesser element would. Soft-start motor drives and switched solid state relay circuits are the typical case.
16) Do I need an indicating semiconductor fuse, or will the A70QS work?
The Mersen A70QS 22F items are ceramic-body ferrule fuses for clip mounting in inverters, UPS systems, solid state relays, and motor drives. If your control scheme relies on a visual or microswitch blown-fuse indicator, note that the Bussmann FBP and Bussmann KAX series are both non-indicating designs as well, so indication would have to come from a separate monitoring method in either case. Decide this before the panel is wired, since the holder and any indicator accessory are sized to the fuse body.
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Does the Mersen A70QS50-22F come with a warranty?
Absolutely. The Mersen A70QS50-22F is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
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