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Square D QOB21251021 Miniature Circuit Breaker
- 125A
- 2 Pole
- Bolt-On
Square D
QOB21251021
Miniature Circuit Breaker
Brand
Square D
SKU
QOB21251021
Quantity
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Square D QOB21251021 - 125A 2 Pole Miniature Circuit Breaker
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Description
Built for commercial applications, the Square D QOB21251021 delivers 125A of thermal-magnetic protection. This two-pole breaker features a factory-installed 120-240V AC shunt trip (1021 suffix), allowing remote tripping via a push-button or pilot device. It installs into Square D NQ and NQOD panelboards, utilizing a bolt-on mounting style for a stable connection. The box lugs accept 4 AWG to 2/0 AWG wire. Rated 10 kAIC at 120/240V, it includes a Visi-Trip indicator and is HACR rated.Specifications
| Brand | Square D |
|---|---|
| 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, HACR |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
Product FAQs
5 answersWhat panelboards are compatible with the QOB21251021?
This bolt-on circuit breaker is designed exclusively for Square D NQ and NQOD panelboards. It will not fit standard QO load centers, which require plug-on breakers.
What does the 1021 suffix indicate on this breaker?
The 1021 suffix indicates that the breaker includes a factory-installed 120/208/240VAC shunt trip. This allows the breaker to be tripped remotely using a push button or pilot device, which is commonly required for emergency stop applications.
How many panel spaces does the QOB21251021 require?
This breaker requires 3 panel spaces. While it is a 2-pole breaker, the factory-installed shunt trip module occupies an additional space in the panelboard.
What wire sizes are accepted by the box lugs on this breaker?
The box lugs accept 4 AWG to 2/0 AWG wire and are rated for use with both copper and aluminum conductors.
Is this breaker suitable for use in HVAC applications?
Yes, the QOB21251021 is HACR rated, making it suitable for heating, air conditioning, and refrigeration equipment applications.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 205 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
205 reviews
- BLBOOSTIX L.Verified BuyerReviewingSquare D QOB220 - 20A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/17/26QOB220
That's nice breakers!
- PHPaul H.Verified BuyerReviewingSquare D QOB330 - 30A 3 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/5/26Quick shipping and delivery
Shipped and delivered on time for installation at one of our projects. Thank you!
- RMRick M.Verified BuyerReviewingSquare D QOB220 - 20A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/3/26Project Mgr
Just what I needed.
- DHDoug H.Verified BuyerReviewingSquare D QOB220 - 20A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/3/26Square D QOB breakers
As always, our order arrived timely, and accurate. You can’t beat their prices that’s why we have used this company for years.
- RKRyan K.Verified BuyerReviewingSquare D QOB230VH - 30A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars7/1/26Awesome
Worked great