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Square D QO21001021 Miniature Circuit Breaker
- 100A
- 2 Pole
- Plug-On
Square D
QO21001021
Miniature Circuit Breaker
Brand
Square D
SKU
QO21001021
Quantity
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Square D QO21001021 - 100A 2 Pole Miniature Circuit Breaker
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Description
Engineered for remote tripping, the QO21001021 includes a factory-installed 120/208/240VAC shunt trip mechanism. This allows automated systems to open the 100-amp circuit from a remote location, ideal for emergency stops. The plug-on design fits seamlessly into standard Square D QO load centers and NQ panelboards. It requires three pole spaces total due to the attached shunt trip module. Along with standard protection, it features the Visi-Trip red flag for quick visual status confirmation.Specifications
| Brand | Square D |
|---|---|
| Part Number | QO21001021 |
| Series | QO |
| Amperage | 100A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120VAC, 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120VAC, 10kA @ 120/240VAC |
| Frame Type | QO |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | QO Load Centers, NQ 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 | Shunt Trip |
| 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, Common Trip |
Product FAQs
5 answersWhat does the 1021 suffix indicate on the QO21001021 breaker?
The 1021 suffix means the breaker is equipped with a factory-installed 120/208/240VAC shunt trip accessory. This allows the breaker to be opened remotely via a control signal, which is commonly used for emergency stops or automated control systems.
How many panel spaces does the QO21001021 require?
It requires three standard 0.75-inch spaces. The 100A 2-pole breaker occupies two spaces, and the attached shunt trip module requires one additional space.
Can this breaker be installed in a Square D Homeline panel?
No. Square D QO circuit breakers have a specific plug-on mounting clip and are not interchangeable with Homeline panels. The QO21001021 must be installed in a compatible QO load center or NQ panelboard.
Does the QO21001021 include a visual trip indicator?
Yes, it features the Square D Visi-Trip indicator. When the breaker trips due to an overcurrent event or a remote shunt trip signal, a red flag appears in the indicator window for quick identification in the panel.
What control voltage is required to activate the shunt trip mechanism?
The factory-installed shunt trip coil is rated to operate on a 120VAC, 208VAC, or 240VAC control voltage signal.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 285 reviews.
Reviews Summary
Generated by AI from 100 most recent customer reviews
Last updated 6/13/26
Customers say these circuit breakers arrive quickly and work as described. Fast shipping and competitive pricing are frequently mentioned, with many noting same-day or next-day delivery. Users appreciate the wide inventory, particularly for hard-to-find older-style models unavailable locally. The products function reliably and arrive in good condition. Most customers report straightforward ordering and positive interactions. However, some experienced delivery delays or received incorrect items requiring reordering. A few noted concerns about condition upon arrival or customer service responsiveness.
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Rating
285 reviews
- GCGerard C.Verified BuyerReviewingSquare D QO130GFI - 30A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/21/26Great !
I could not find the breaker in hardwood stores. Superbreakers took car of it in a week.
- RHRoy H.Verified BuyerReviewingSquare D QO280 - 80A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/17/26Square D QO280 - 80A 2 Pole Miniature Circuit Breaker
Exactly as described
- KWKevin W.Verified BuyerReviewingSquare D QO120 - 20A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/15/26Great Price
Brand spanking new!
- CEchristopher e.Verified BuyerReviewingSquare D QO115PDF - 15A Dual Function Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/11/26My breakers
Had a hard time locating these breakers locally, when I did find 1 they wanted to charge me triple what superbreakers charged. Items delivered exactly when they said they would, were exactly what I ordered. Appreciated the ease of ordering, definitely my go to from this point on
- JCJerry C.Verified BuyerReviewingSquare D QO250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/8/26Great quality
No issues