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Square D QOU3401021 Miniature Circuit Breaker
- 40A
- 3 Pole
- Unit Mount
Square D
QOU3401021
Miniature Circuit Breaker
Brand
Square D
SKU
QOU3401021
Quantity
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Square D QOU3401021 - 40A 3 Pole Miniature Circuit Breaker
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Description
Designed for advanced control, the Square D QOU3401021 is a 3-pole, 40A miniature circuit breaker featuring a factory-installed shunt trip. This thermal-magnetic breaker provides reliable overcurrent protection while enabling remote tripping capabilities. The unit mount configuration allows for straightforward installation into DIN rail systems, OEM panels, and control enclosures. With a 10 kAIC rating at 240VAC, it delivers robust performance, is HACR rated, and includes a Visi-Trip indicator.Specifications
| Brand | Square D |
|---|---|
| Series | QOU |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Frame Type | QOU |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | DIN Rail Systems, OEM Panels, Enclosures, Control Panels |
| Wire Gauge | 14-2 AWG (Al/Cu) |
| Max Wire | 2 AWG |
| Min Wire | 14 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Mounting Feet, Padlock Attachment |
|---|---|
| Accessories | Shunt Trip (Factory Installed) |
| Standards | CSA C22.2 No. 5, IEC 60947-2, UL 489, HACR Rated |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip |
Product FAQs
6 answersWhat does the 1021 suffix indicate on the QOU3401021 circuit breaker?
The 1021 suffix indicates that this breaker includes a factory-installed 120/240VAC shunt trip, allowing for remote tripping capabilities.
How is the Square D QOU3401021 breaker mounted?
This breaker features a unit mount design. It can be surface-mounted, flush-mounted, or installed on standard DIN rail systems, making it versatile for OEM panels and control enclosures.
What are the wire size requirements for the QOU3401021 box lugs?
The feed-thru box lugs are designed to accept either aluminum or copper conductors ranging from 14 AWG to 2 AWG, providing flexibility for various panel wiring configurations.
Can the QOU3401021 be used in DC control circuits?
Yes, in addition to its AC ratings, this breaker is rated for 48VDC applications with an interrupting capacity of 5 kAIC, making it suitable for DC control panels and enclosures.
Is the QOU3401021 compatible with standard QO load centers?
No, the QOU series features a unit mount, feed-thru design intended for DIN rails, enclosures, and OEM panels. It will not plug into standard QO load centers or bolt into QOB panelboards.
Does the QOU3401021 feature a visual trip indicator?
Yes, Square D QOU breakers feature a Visi-Trip indicator that provides clear visual confirmation when the breaker has tripped due to an overcurrent or short circuit condition.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 106 reviews.
Reviews Summary
Generated by AI from 99 most recent customer reviews
Last updated 5/14/26
Customers say these circuit breakers function properly and arrive quickly. Many reviews highlight fast shipping, competitive pricing, and reliable product condition upon arrival. Users appreciate the wide selection, including hard-to-find models, and note the breakers work as expected for various applications. Common feedback addresses quick order processing and easy website navigation. Most customers report satisfaction with value and delivery speed, with many indicating they will purchase again.
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Rating
106 reviews
- HLHOMETIGO L.Verified BuyerReviewingSquare D QOU260 - 60A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/7/26Good thing
i recommend this for you
- RGRobert G.Verified BuyerReviewingSquare D QOU340 - 40A 3 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/3/26Circuit breakers
I appreciate the fact that you had these in stock. my Square D distributor does not seem to stock these anymore and it takes a couple weeks to get. your pricing is inline with theirs.
- THTiffany H.Verified BuyerReviewingSquare D QOU115 - 15A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/28/26Will use Super Breakers again
Arrived in a timely manner. Exactly what we needed for a job.
- CSCary S.Verified BuyerReviewingSquare D QOU250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/12/26Just what I ordered
Just what I needed for dock pedestal
- MHMark H.Verified BuyerReviewingSquare D QOU250VH - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/11/26Square D QOU250VH - 50A 2 Pole Miniature Circuit Breaker
Was just what I expected!