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Square D QOU390 Miniature Circuit Breaker
- 90A
- 3 Pole
- Unit Mount
Square D
QOU390
Miniature Circuit Breaker
Brand
Square D
SKU
QOU390
Quantity
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Square D QOU390 - 90A 3 Pole Miniature Circuit Breaker
New
Quantity
Quantity
Square D QOU390 - 90A 3 Pole Miniature Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOU390 |
| Series | QOU |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 60VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 5kA @ 60VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | DIN Rail Systems, OEM Panels, Enclosures |
| Wire Gauge | 12-2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 12 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Mounting Feet, Padlock Attachment, Shunt Trip, Auxiliary Switch |
|---|---|
| Accessories | Visi-Trip Indicator |
| Standards | CSA C22.2 No. 5, IEC 60947-2, UL 489 |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, Common Trip |
Sold out
Quantity
Square D QOU390 - 90A 3 Pole Miniature Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOU390-R |
| Series | QOU |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 60VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 5kA @ 60VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | DIN Rail Systems, OEM Panels, Enclosures |
| Wire Gauge | 12-2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 12 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Mounting Feet, Padlock Attachment, Shunt Trip, Auxiliary Switch |
|---|---|
| Accessories | Visi-Trip Indicator |
| Standards | CSA C22.2 No. 5, IEC 60947-2, UL 489 |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, Common Trip |
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Description
Part of the QOU series, this 90A miniature circuit breaker offers dependable thermal-magnetic trip functions for commercial and industrial loads. It is engineered for versatile installation across various environments. Designed to mount onto DIN rails or flat surfaces within OEM panels, it provides a flexible solution for custom enclosures. The box lug terminals accommodate aluminum or copper wiring from 12 to 2/0 AWG.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOU390 |
| Series | QOU |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 240VAC, 60VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 5kA @ 60VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | DIN Rail Systems, OEM Panels, Enclosures |
| Wire Gauge | 12-2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 12 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Mounting Feet, Padlock Attachment, Shunt Trip, Auxiliary Switch |
|---|---|
| Accessories | Visi-Trip Indicator |
| Standards | CSA C22.2 No. 5, IEC 60947-2, UL 489 |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, Common Trip |
Product FAQs
6 answersCan I install the QOU390 in a standard Square D QO residential load center?
No. While it belongs to the broader QO family, the QOU390 is a unit-mount (cable-in/cable-out) breaker. It lacks the plug-on jaws required for QO load centers and is strictly designed for DIN rails, OEM panels, and individual enclosures.
How do you mount the QOU390 in an OEM control panel?
This breaker can be snapped directly onto a standard 35mm symmetrical DIN rail. It can also be surface-mounted or flush-mounted using compatible Square D QOUMF mounting feet.
Is the QOU390 suitable for protecting HVAC equipment?
Yes. This model is UL Listed as an HACR-type circuit breaker, making it approved for use with heating, air conditioning, and refrigeration motor group applications.
Are the line and load lugs on the QOU390 reversible?
No. Unlike low-amperage QOU breakers which feature reversible lugs, the high-amperage QOU models (80A through 125A) are manufactured with non-reversible line and load lugs.
Does this breaker feature a visual trip indicator?
Yes, it includes Square D Visi-Trip technology. If the breaker trips due to an overload or short circuit, the handle rests in a center position and exposes a highly visible red indicator to easily identify the faulted circuit.
How does the breaker respond to a fault on a single phase?
The QOU390 features an internal common trip mechanism linked to a single handle. If an overcurrent or short circuit occurs on any one phase, all three poles will open simultaneously to completely de-energize the circuit.
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Free Shipping Policy
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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We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
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Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
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!