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Square D QOU2125 Miniature Circuit Breaker
- 125A
- 2 Pole
- Unit Mount
Square D
QOU2125
Miniature Circuit Breaker
Brand
Square D
SKU
QOU2125
Quantity
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Square D QOU2125 - 125A 2 Pole Miniature Circuit Breaker
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Description
Engineered for commercial and industrial applications, this 125A miniature breaker provides reliable thermal-magnetic protection. It handles demanding electrical loads while maintaining a compact footprint. The unit-mount design allows for flexible installation into OEM enclosures, control panels, and standard DIN rail systems. It accommodates 12 AWG to 2/0 AWG wiring through versatile reversible box lugs. Featuring a 10kAIC rating, it includes Square D's signature Visi-Trip indicator.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOU2125 |
| Series | QOU |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Unit Mount |
| Voltage | 120/240VAC, 60VDC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC, 5kA @ 60VDC |
| Frame Type | QOU |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | DIN Rail Systems, OEM Panels, Control Panels |
| Wire Gauge | 12 AWG - 2/0 AWG |
| 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 |
| Available Options | Mounting Feet, Padlock Attachment, Finger Safe Covers, Auxiliary Switch, Alarm Switch |
|---|---|
| Accessories | Line and Load Lugs Included |
| Standards | CSA C22.2 No. 5, IEC 60947-2, UL 489, HACR Rated |
| Approval | CSA, HACR, IEC, UL |
| Temp Rating | 40C |
Product FAQs
10 answersCan I use the QOU2125 breaker in a standard Square D QO load center?
No. While they share the same internal thermal-magnetic tripping mechanism, QO breakers are plug-on units designed specifically for QO panelboards. The QOU2125 is a unit-mount breaker built for surface mounting, flush mounting, or DIN rail installations in control panels and OEM equipment.
Does the QOU2125 require a separate adapter to mount on a DIN rail?
No special adapter is required. The QOU frame features built-in slots in the molded case that allow it to snap directly onto standard 35mm DIN rails (DIN/EU 50 022).
Is the QOU2125 circuit breaker suitable for DC power systems?
Yes. In addition to its primary AC rating, the QOU2125 is listed for use on 60VDC systems with a 5kA interrupting capacity. This makes it compatible with specific control circuits, off-grid equipment, and battery applications operating within that voltage limit.
What does the LI trip function code indicate on this breaker?
The LI designation means this thermal-magnetic breaker features both Long-Time (L) and Instantaneous (I) trip functions. The long-time function provides a delayed trip for sustained overloads, while the instantaneous function immediately opens the circuit during a high-current short circuit.
Can this 2-pole breaker be used on a 3-phase electrical system?
Two-pole QOU circuit breakers rated for 120/240VAC are UL Listed for use on single-phase three-wire systems, as well as 208Y/120VAC three-phase four-wire systems. They cannot be used on 240V delta systems.
Is there an alternative part number for the QOU2125?
Depending on the distributor or inventory system, this breaker is occasionally listed as Q0U2125, utilizing a numerical zero instead of the letter O. However, QOU2125 remains the official Schneider Electric and Square D catalog number.
Is this breaker HACR rated for HVAC applications?
Yes. Square D QOU miniature circuit breakers are HACR rated, meaning they are certified for use with heating, air conditioning, and refrigeration equipment that requires this specific overcurrent protection designation.
How do the surface mounting brackets work on the QOU series?
QOU miniature circuit breakers include field-installable mounting brackets for line and load side support. These brackets are reversible and can be attached to either the front or back of the molded case, depending on your flush or surface mounting requirements.
Will both poles trip simultaneously if only one line experiences an overload?
Yes. The QOU2125 features an internal crossbar mechanism designed for the common tripping of all poles. If an overload or short circuit occurs on one pole, the internal mechanism will automatically and simultaneously open the second pole.
Does the QOU2125 accept both copper and aluminum conductors?
Yes. The slotted box lugs on the QOU2125 are dual-rated to accept both aluminum and copper wiring. The terminals accommodate wire gauges from 12 AWG up to 2/0 AWG.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 108 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
108 reviews
- MMMichael M.Verified BuyerReviewingSquare D QOU3100 - 100A 3 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/13/26Excellent Customer service
We had a new piece of equipment come in that has a higher nameplate rating than was originally conveyed. The lead time from the supply house was outrageous at 10-12 weeks. We ordered it from SuperBreakers and had the equipment running in 3 days. Angel the sales rep. followed up several times first to confirm the order arrived and second that it was the correct
breaker.
- 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.