Square D QOU340-1200 QOU3401200 - 40A 3 Pole Miniature Circuit Breaker
- 40A
- 3 Pole
- Unit Mount
Square D
QOU340-1200
QOU3401200 - 40A 3 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QOU340-1200
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Square D QOU3401200 - 40A 3 Pole Miniature Circuit Breaker
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Description
Engineered for versatile power distribution, the Square D QOU340-1200 is a 3-pole, 40A miniature circuit breaker equipped with a factory-installed auxiliary switch. It delivers dependable thermal-magnetic protection for commercial and industrial environments. This unit mount breaker installs easily into DIN rail systems, OEM panels, and enclosures. It features reversible line and load lugs for flexible wiring. Rated for 10 kAIC at 240VAC, it is HACR rated and includes Visi-Trip technology.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOU340-1200 |
| 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, Control Panels, Enclosures |
| 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 | Auxiliary Switch (Factory Installed), Line and Load Lugs Included |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
Product FAQs
6 answersWhat does the -1200 suffix mean on the QOU340-1200 catalog number?
The -1200 suffix indicates that this breaker comes with a factory-installed auxiliary switch. This switch provides a remote signal to monitor whether the breaker contacts are open or closed.
Can I install this QOU breaker in a standard Square D load center?
No. QOU series breakers are unit-mount, feed-thru breakers designed for OEM panels, control enclosures, and DIN rail systems. They do not plug or bolt into standard QO or NQ panelboards.
How do I mount this breaker onto a DIN rail?
While QOU breakers are compatible with DIN rail systems, they require a separate Square D DIN rail mounting bracket or adapter clip to secure the unit to the rail.
Can I field-install a shunt trip on this breaker?
No. Square D QOU breakers only accept one accessory, and this specific model already includes a factory-installed auxiliary switch. Furthermore, internal accessories for the QOU line cannot be added in the field.
How does the Visi-Trip feature help with troubleshooting?
The breaker includes a red Visi-Trip indicator that becomes visible when the unit trips. The handle also snaps to a center position, allowing you to quickly identify a tripped circuit inside a crowded control panel.
Is this breaker suitable for HVAC motor loads?
Yes, this thermal-magnetic breaker is HACR rated, meaning it is approved for use with multi-motor and combination loads commonly found in heating, air conditioning, and refrigeration equipment.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 107 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
107 reviews
- VBVictor B.Verified BuyerReviewingSquare D QOU280 - 80A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/6/26Square D QOU280
As advertised, works great under normal load conditions. We Recomend this product. Service and shipping was great and easy. Pleasure to deal with.
- 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