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Square D QOB340-1021 QOB3401021 - 40A 3 Pole Miniature Circuit Breaker
- 40A
- 3 Pole
- Bolt-On
Square D
QOB340-1021
QOB3401021 - 40A 3 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QOB340-1021
Quantity
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Square D QOB3401021 - 40A 3 Pole Miniature Circuit Breaker
Re-Certified
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Square D QOB3401021 - 40A 3 Pole Miniature Circuit Breaker
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| Brand | Square D |
|---|---|
| Part Number | QOB3401021 |
| Series | QOB |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 120VAC, 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 120VAC, 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | NQ Panelboards, NQOD Panelboards |
| Wire Gauge | 8-2 AWG (Al/Cu) |
| Max Wire | 2 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Auxiliary Switch, Alarm Switch |
|---|---|
| Accessories | Shunt Trip (Factory Installed), Load Side Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
Sold out
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Square D QOB3401021 - 40A 3 Pole Miniature Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOB3401021-R |
| Series | QOB |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 120VAC, 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 120VAC, 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | NQ Panelboards, NQOD Panelboards |
| Wire Gauge | 8-2 AWG (Al/Cu) |
| Max Wire | 2 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Auxiliary Switch, Alarm Switch |
|---|---|
| Accessories | Shunt Trip (Factory Installed), Load Side Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
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Description
Part of the QO family, the QOB340-1021 is a 40-amp, three-pole miniature circuit breaker. It delivers reliable thermal-magnetic protection against overloads for commercial distribution. This model is engineered to bolt securely into Square D NQ and NQOD panelboards. The box lug terminals accept 8-2 AWG aluminum or copper wire. A standout feature is the factory-installed 120/240V AC shunt trip, allowing remote operation. It maintains a 10kAIC rating and includes the Visi-Trip indicator.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOB3401021-R |
| Series | QOB |
| Amperage | 40A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 120VAC, 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 120VAC, 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | NQ Panelboards, NQOD Panelboards |
| Wire Gauge | 8-2 AWG (Al/Cu) |
| Max Wire | 2 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Auxiliary Switch, Alarm Switch |
|---|---|
| Accessories | Shunt Trip (Factory Installed), Load Side Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
Product FAQs
5 answersWhat does the 1021 suffix mean in the QOB3401021 catalog number?
The 1021 suffix indicates that this circuit breaker includes a factory-installed 120/240V AC shunt trip accessory. This allows the breaker to be tripped from a remote location using a separate control circuit.
How many panel spaces does the QOB3401021 require for installation?
This breaker requires four panel spaces. The 3-pole breaker itself takes three spaces, and the factory-installed shunt trip accessory requires one additional pole space.
Can I use a QOB3401021 in place of a QO3401021?
No. While both are 40A, 3-pole breakers with a shunt trip, the QOB3401021 features a bolt-on connection for NQ and NQOD panelboards. The QO version uses a plug-on connection designed for standard QO load centers.
Does this breaker include a visual trip indicator?
Yes, Square D QOB breakers feature a Visi-Trip indicator. This provides a highly visible red flag when the breaker has tripped due to an overload or short circuit, making it easier to identify the faulted circuit.
Can the shunt trip accessory be removed or modified in the field?
No, the 120/240V AC shunt trip on the QOB3401021 is factory-installed. Miniature QOB breakers do not support field-installable internal accessories.
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Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 211 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
211 reviews
- MLMike L.Verified BuyerReviewingSquare D QOB250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/9/26breaker orders
Breaker worked out great
Can not be happier with the quick shipping
- RCRichard C.Verified BuyerReviewingSquare D QOB380 - 80A 3 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/7/26Great price quick turn around
Thank you for getting me the breaker in a timely fashion
- DSDarren S.Verified BuyerReviewingSquare D QOB250 - 50A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/5/26Airport taxi lighting
After contactor replacement we discovered bad breakers and were able to get replacements from Super Breakers in 2 days. THANK YOU SUPER BREAKERS..
- MRMiguel R.Verified BuyerReviewingSquare D QOB220GFI - 20A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/1/26Excellent
Excellent product and service
- MRMiguel R.Verified BuyerReviewingSquare D QOB230GFI - 30A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/1/26Excellent
Excellent product and service