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Square D QOB31001021 Miniature Circuit Breaker
- 100A
- 3 Pole
- Bolt-On
Square D
QOB31001021
Miniature Circuit Breaker
Brand
Square D
SKU
QOB31001021
Quantity
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Square D QOB31001021 - 100A 3 Pole Miniature Circuit Breaker
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Description
Built for heavy-duty three-phase loads, this 100A device integrates a 120/208/240VAC shunt trip for automated or remote shutoff requirements. It bolts into Square D NQ and NQOD panelboards, ensuring a rigid connection that withstands industrial vibrations. The unit provides reliable 10kAIC thermal-magnetic protection and features the Visi-Trip window to simplify maintenance checks.Specifications
| Brand | Square D |
|---|---|
| Series | QOB |
| Amperage | 100A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 120/240VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC |
| Frame Type | QOB |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | Square D NQ Panelboards, Square D 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 |
|---|---|
| Accessories | Load Side Lugs Included, Shunt Trip (Factory Installed) |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip |
Product FAQs
7 answersCan I install the QOB31001021 in a standard QO load center?
No. The QOB31001021 is a bolt-on circuit breaker designed specifically for Square D NQ and NQOD panelboards. Standard QO load centers require plug-on QO breakers.
What does the 1021 suffix mean on the QOB31001021?
The 1021 suffix indicates that this breaker includes a factory-installed shunt trip accessory rated for 120, 208, or 240 VAC. This allows the breaker to be tripped remotely via a separate control circuit.
How many panel spaces does the QOB31001021 require?
Although it is a 3-pole breaker, the factory-installed shunt trip module requires an additional pole space. Therefore, this breaker takes up a total of four panel spaces in an NQ or NQOD panelboard.
What wire sizes are accepted by the shunt trip terminals on this breaker?
The shunt trip terminals on the QOB31001021 accept up to two 14 AWG to 12 AWG copper wires. The hot and neutral control wires can be connected to either terminal.
Is the QOB31001021 HACR rated?
Yes. Like most standard QOB breakers, this unit is HACR rated, making it suitable for group motor applications in heating, air conditioning, and refrigeration equipment.
What does the LI trip function code mean for this breaker?
The LI designation indicates that the thermal magnetic trip unit provides Long-Time (thermal) protection against overloads and Instantaneous (magnetic) protection against short circuits. Both trip settings are fixed on this model.
How does the Visi-Trip indicator work on this breaker?
The Visi-Trip indicator provides a clear visual cue when the breaker has tripped. The handle moves to a center position, and a highly visible red indicator appears in a window on the breaker case, making it easy to identify the tripped circuit in a crowded panel.
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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