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Square D QOU340 Miniature Circuit Breaker
- 40A
- 3 Pole
- Unit Mount
Square D
QOU340
Miniature Circuit Breaker
Brand
Square D
SKU
QOU340
Quantity
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Square D QOU340 - 40A 3 Pole Miniature Circuit Breaker
New
Quantity
Quantity
Square D QOU340 - 40A 3 Pole Miniature Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOU340 |
| 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 | OEM Panels, Control Panels, DIN Rail Systems, 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 | Padlock Attachment, Mounting Feet, Quick Connectors |
|---|---|
| Accessories | Line and Load Lugs Included, Mounting Hardware |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, UL 489 |
| Approval | CE, CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Reverse Feed |
Sold out
Quantity
Square D QOU340 - 40A 3 Pole Miniature Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOU340-R |
| 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 | OEM Panels, Control Panels, DIN Rail Systems, 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 | Padlock Attachment, Mounting Feet, Quick Connectors |
|---|---|
| Accessories | Line and Load Lugs Included, Mounting Hardware |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, UL 489 |
| Approval | CE, CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Reverse Feed |
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Description
Built for commercial applications, the QOU340 is a 3-pole, 40A miniature circuit breaker from Square D. It provides reliable power distribution for OEM panels and enclosures. The unit mount configuration is compatible with DIN rail systems. It includes box lugs that accept 14-2 AWG wire, supporting surface, flush, or DIN rail mounting. With a 10 kAIC rating at 240VAC, it ensures robust overload protection. The HACR-rated unit also features a Visi-Trip indicator for fast troubleshooting.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOU340 |
| 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 | OEM Panels, Control Panels, DIN Rail Systems, 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 | Padlock Attachment, Mounting Feet, Quick Connectors |
|---|---|
| Accessories | Line and Load Lugs Included, Mounting Hardware |
| Standards | CSA C22.2 No. 5, HACR, IEC 60947-2, UL 489 |
| Approval | CE, CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Reverse Feed |
Product FAQs
5 answersHow is the QOU340 circuit breaker mounted?
This feed-thru breaker is designed for surface, flush, or DIN rail mounting. Installing it on a standard 35mm DIN rail requires a compatible Square D DIN rail adapter bracket.
Can I install the QOU340 in a standard Square D residential load center?
No. While it shares thermal-magnetic trip technology with the standard QO family, the QOU340 is a unit-mount breaker. It is designed for OEM equipment, custom enclosures, and control panels rather than plug-on or bolt-on load centers.
Is the QOU340 suitable for heating and cooling equipment?
Yes, it is HACR rated, making it approved for use with compatible heating, air conditioning, and refrigeration systems.
Does this breaker include a visual trip indicator?
Yes, it features the Square D Visi-Trip indicator. A highly visible red flag appears in the indicator window when the breaker trips, making it easy to identify in a crowded control panel.
Are the terminal connections reversible on the QOU340?
No, this unit utilizes a standard cable-in and cable-out design with fixed, non-reversible slotted box lugs on both the line and load sides.
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Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
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All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
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!