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Square D QOB240-1021 QOB2401021 - 40A 2 Pole Miniature Circuit Breaker
- 40A
- 2 Pole
- Bolt-On
Square D
QOB240-1021
QOB2401021 - 40A 2 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QOB240-1021
Quantity
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Square D QOB2401021 - 40A 2 Pole Miniature Circuit Breaker
New
Quantity
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Quantity
Square D QOB2401021 - 40A 2 Pole Miniature Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOB2401021 |
| Series | QOB |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | QOB |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | Square D NQ Panelboards, Square D 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, Padlock Attachment |
|---|---|
| Accessories | Shunt Trip |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Common Trip, Visual Trip Indicator |
Sold out
Quantity
Square D QOB2401021 - 40A 2 Pole Miniature Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | QOB2401021-R |
| Series | QOB |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | QOB |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | Square D NQ Panelboards, Square D 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, Padlock Attachment |
|---|---|
| Accessories | Shunt Trip |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Common Trip, Visual Trip Indicator |
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Description
Delivering both overcurrent defense and remote control, this 40-amp miniature breaker is ideal for complex commercial electrical systems. The two-pole configuration utilizes proven thermal-magnetic trip technology. Fastening securely to the busbar, it fits seamlessly into Square D NQ and older NQOD load centers. The bolt-on connection provides excellent stability in high-vibration industrial settings. The standout feature is the built-in 120-240VAC shunt trip for automated disconnects.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOB2401021 |
| Series | QOB |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | QOB |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | Square D NQ Panelboards, Square D 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, Padlock Attachment |
|---|---|
| Accessories | Shunt Trip |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Common Trip, Visual Trip Indicator |
Product FAQs
5 answersWhich panelboards are compatible with the Square D QOB2401021 circuit breaker?
This bolt-on breaker is designed for use in Square D NQ and legacy NQOD series panelboards. It cannot be installed in standard QO load centers, which require plug-on breakers.
What does the 1021 suffix indicate on the QOB2401021 catalog number?
The 1021 suffix designates a factory-installed shunt trip accessory. This shunt trip operates on a 120/208/240 VAC control voltage, allowing the breaker to be tripped remotely for emergency stops or automated control systems.
What wire sizes and materials are accepted by the terminals on the QOB2401021?
The box lugs on this 40-amp breaker accept 8 AWG to 2 AWG aluminum or copper conductors. Ensure proper torque specifications are followed during installation.
Can the QOB2401021 be used in DC applications?
Yes, this thermal-magnetic breaker is rated for use in DC systems up to 48 VDC, providing a maximum interrupting capacity of 5 kA at that voltage.
Does the QOB2401021 feature a Visi-Trip indicator?
Yes, this model includes the standard Square D Visi-Trip indicator. When the breaker trips due to an overcurrent event or is actuated by the remote shunt trip, a highly visible red indicator appears in the window to help quickly identify the tripped circuit.
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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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All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
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