Square D QOB3100-1021 QOB31001021 - 100A 3 Pole Miniature Circuit Breaker
- 100A
- 3 Pole
- Bolt-On
Square D
QOB3100-1021
QOB31001021 - 100A 3 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QOB3100-1021
Quantity
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Square D QOB31001021 - 100A 3 Pole Miniature Circuit Breaker
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Description
Engineered for remote operation, this 100A, 3-pole miniature circuit breaker includes a factory-installed shunt trip accessory. It provides reliable thermal-magnetic protection for commercial systems, operating at 240VAC with a 10kAIC rating. This bolt-on breaker mounts securely into Square D NQ and NQOD panelboards. The box lug terminals accommodate 4 AWG to 2/0 AWG wire for stable connections. A built-in Visi-Trip indicator provides clear visual confirmation when the breaker has tripped.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOB3100-1021 |
| 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 | 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 |
|---|---|
| Accessories | Shunt Trip (120/208/240VAC) |
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, Common Trip |
Product FAQs
7 answersWhich panelboards are compatible with the QOB3100-1021 circuit breaker?
This bolt-on breaker is designed exclusively for Square D NQ and NQOD series panelboards. It cannot be installed in standard QO load centers, which require plug-on mounting.
What does the 1021 suffix indicate on the QOB3100-1021 catalog number?
The 1021 suffix designates a factory-installed shunt trip accessory. This allows the breaker to be opened remotely using a 120V to 240V AC control signal, commonly utilized for emergency stop circuits or automated shutdown systems.
What is the advantage of the bolt-on connection for the QOB3100-1021?
The bolt-on mounting secures the breaker directly to the panelboard busbar. This provides a highly rigid, vibration-resistant connection that is ideal for heavy commercial and industrial applications.
What wire sizes are accepted by the terminals on this 100A breaker?
The box lugs accept 4 AWG to 2/0 AWG aluminum or copper conductors. Always verify the specific torque requirements printed on the breaker before terminating the conductors.
Does the QOB3100-1021 include a visual trip indicator?
Yes, it features the standard Square D Visi-Trip indicator. When the breaker trips due to an overcurrent, short circuit, or a remote shunt trip signal, a red flag appears in the window to help quickly identify the open circuit.
Can the QOB3100-1021 be used in DC applications?
Yes, in addition to its standard AC ratings, this thermal-magnetic breaker is rated for use on 48VDC systems.
Can I substitute a QO3100-1021 for the QOB3100-1021?
No. While both are 100A, 3-pole breakers equipped with a shunt trip, the QO version is a plug-on breaker meant for load centers. The QOB version is a bolt-on breaker required for NQ and NQOD panelboards.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 206 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
206 reviews
- KHKristopher H.Verified BuyerReviewingSquare D QOB120GFI - 20A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/28/26Great Price!
Great price. Fast delivery. My local electric distributor wanted double for the same breaker, so it was a no brainer to order this one. Ordered another one since with the same great service.
- 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.