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Square D QOB3901021 Miniature Circuit Breaker
- 90A
- 3 Pole
- Bolt-On
Square D
QOB3901021
Miniature Circuit Breaker
Brand
Square D
SKU
QOB3901021
Quantity
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Square D QOB3901021 - 90A 3 Pole Miniature Circuit Breaker
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Description
Built for commercial distribution, the Square D QOB3901021 delivers reliable overcurrent protection with remote tripping capabilities. This 3-pole, 90A miniature circuit breaker features a thermal-magnetic trip mechanism and a 10kAIC rating at 240V. Designed for secure installation, it bolts into Square D NQ and NQOD panelboards. The 1021 suffix indicates a factory-installed 120/240VAC shunt trip, allowing the breaker to be opened remotely. It also includes a Visi-Trip indicator.Specifications
| Brand | Square D |
|---|---|
| Series | QOB |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| 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 | Auxiliary Switch, Alarm Switch, Padlock Attachment, Handle Tie, Handle Lock |
|---|---|
| Accessories | Shunt Trip |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip, Trip-Free Mechanism, Quick-Make/Quick-Break |
Product FAQs
4 answersWhat does the 1021 suffix mean on the QOB3901021 catalog number?
The 1021 suffix indicates that this breaker includes a factory-installed 120/240VAC shunt trip accessory. This allows the breaker to be tripped remotely using an external control signal.
Which panelboards are compatible with the QOB3901021 circuit breaker?
This bolt-on circuit breaker is designed specifically for use in Square D NQ and NQOD series panelboards. It is not compatible with standard QO load centers, which require plug-on breakers.
How does the QOB3901021 mount into the panelboard?
It features a bolt-on connection, which secures directly to the bus bar of NQ or NQOD panelboards using screws. This provides a highly reliable connection for commercial and industrial applications.
Does this breaker feature a Visi-Trip indicator?
Yes, it includes the Square D Visi-Trip visual indicator, which displays a highly visible red flag when the breaker has tripped. This makes it easy to identify a faulted 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