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Square D QOB2125-1021 QOB21251021 - 125A 2 Pole Miniature Circuit Breaker
- 125A
- 2 Pole
- Bolt-On
Square D
QOB2125-1021
QOB21251021 - 125A 2 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QOB2125-1021
Quantity
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Square D QOB21251021 - 125A 2 Pole Miniature Circuit Breaker
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Description
Delivering 125A of thermal-magnetic protection, the Square D QOB2125-1021 is built for commercial distribution. This two-pole breaker is rated for 120/240VAC and provides a 10kAIC interrupting capacity. It installs into Square D NQ and NQOD panelboards, utilizing a bolt-on mounting style for a secure connection. The unit accepts 4 AWG to 2/0 AWG wiring via box lugs. A factory-installed shunt trip allows the breaker to be opened remotely, making it ideal for emergency stop applications.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOB2125-1021 |
| Series | QOB |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120VAC, 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120VAC, 10kA @ 120/240VAC |
| Frame Type | QOB |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | NQ Panelboards, NQOD Panelboards |
| Wire Gauge | 4 AWG-2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment, Handle Tie |
|---|---|
| Accessories | Shunt Trip (Factory Installed) |
| Standards | CSA C22.2 No. 5, UL 489, NEMA AB 1 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
Product FAQs
7 answersWhat does the -1021 suffix indicate on the QOB2125-1021?
The -1021 suffix means this breaker includes a factory-installed 120/240V AC shunt trip. This accessory allows the breaker to be opened remotely via a control signal from a push-button or pilot device.
How many panel spaces does this breaker occupy?
Although it is a 2-pole breaker, the QOB2125-1021 requires 3 panel spaces. The factory-installed shunt trip occupies the additional space.
Which panelboards accept the QOB2125-1021?
This bolt-on breaker is compatible with Square D NQ and NQOD panelboards. It is not compatible with standard QO load centers, which require plug-on connections.
What wire sizes are compatible with the terminals on this breaker?
The box lugs on this breaker accept 4 AWG to 2/0 AWG copper or aluminum conductors.
Is the QOB2125-1021 suitable for HVAC applications?
Yes, this breaker is HACR rated, meaning it is approved for use with heating, air conditioning, and refrigeration equipment.
How can I tell if this breaker has tripped?
It features the Square D Visi-Trip indicator, which displays a highly visible red flag in the window when the breaker has tripped, making it easy to identify in a crowded panelboard.
Are the trip settings adjustable on this breaker?
No, the QOB2125-1021 features fixed thermal-magnetic trip settings for both long-time and instantaneous functions.
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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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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 212 reviews.
Reviews Summary
Generated by AI from 100 most recent customer reviews
Last updated 3/11/26
Customers say these electrical breakers arrive exactly as ordered and work perfectly for their intended applications. They consistently praise the competitive pricing, which many report is significantly lower than local suppliers. Fast shipping and prompt delivery are frequently highlighted, with many receiving orders within days or even next-day delivery for urgent needs. The breakers arrive well-packaged and in excellent condition. Many reviews emphasize the company's extensive inventory availability, particularly for hard-to-find breakers. One customer experienced difficulty with order cancellation and was charged a restocking fee, which caused dissatisfaction.
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Rating
212 reviews
- SJSheldon J. H.Verified BuyerReviewingSquare D QOB240 - 40A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/12/26Installer
Good price, worked great.
- MLMike L.Verified BuyerReviewingSquare D QOB250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/9/26breaker orders
Breaker worked out great
Can not be happier with the quick shipping
- RCRichard C.Verified BuyerReviewingSquare D QOB380 - 80A 3 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/7/26Great price quick turn around
Thank you for getting me the breaker in a timely fashion
- DSDarren S.Verified BuyerReviewingSquare D QOB250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/5/26Airport taxi lighting
After contactor replacement we discovered bad breakers and were able to get replacements from Super Breakers in 2 days. THANK YOU SUPER BREAKERS..
- MRMiguel R.Verified BuyerReviewingSquare D QOB220GFI - 20A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/1/26Excellent
Excellent product and service