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Square D QO240 Miniature Circuit Breaker
- 40A
- 2 Pole
- Plug-On
Square D
QO240
Miniature Circuit Breaker
Brand
Square D
SKU
QO240
Quantity
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Square D QO240 - 40A 2 Pole Miniature Circuit Breaker
New
Quantity
Quantity
Square D QO240 - 40A 2 Pole Miniature Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Part Number | QO240 |
| Series | QO |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC, 48VDC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC, 5kA @ 48VDC |
| Frame Type | QO |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | QO Load Centers, NQ Panelboards, NQOD Panelboards, Speed-D Switchboards |
| 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 | Padlock Attachment |
|---|---|
| Accessories | Visi-Trip Indicator |
| 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, Quick-Make/Quick-Break, Trip-Free Mechanism, Mercury Free, RoHS Compliant |
Sold out
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Square D QO240 - 40A 2 Pole Miniature Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | QO240-R |
| Series | QO |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC, 48VDC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC, 5kA @ 48VDC |
| Frame Type | QO |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | QO Load Centers, NQ Panelboards, NQOD Panelboards, Speed-D Switchboards |
| 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 | Padlock Attachment |
|---|---|
| Accessories | Visi-Trip Indicator |
| 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, Quick-Make/Quick-Break, Trip-Free Mechanism, Mercury Free, RoHS Compliant |
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Description
Engineered for residential and commercial applications, this 40A, two-pole miniature circuit breaker delivers reliable thermal-magnetic overcurrent protection. It mounts into Square D QO load centers, NQ panelboards, and Speed-D switchboards using a standard plug-on connection. Rated for 10kAIC at 120/240VAC, the unit features an exclusive Visi-Trip indicator that provides clear visual confirmation when a fault occurs, simplifying troubleshooting and reducing downtime.Specifications
| Brand | Square D |
|---|---|
| Part Number | QO240 |
| Series | QO |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC, 48VDC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC, 5kA @ 48VDC |
| Frame Type | QO |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | QO Load Centers, NQ Panelboards, NQOD Panelboards, Speed-D Switchboards |
| 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 | Padlock Attachment |
|---|---|
| Accessories | Visi-Trip Indicator |
| 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, Quick-Make/Quick-Break, Trip-Free Mechanism, Mercury Free, RoHS Compliant |
Product FAQs
6 answersCan I install the QO240 circuit breaker in a Square D Homeline panel?
No. Although both lines are manufactured by Square D, QO and Homeline load centers use completely different busbar configurations. This plug-on breaker is engineered exclusively for QO load centers, NQ panelboards, NQOD panelboards, and Speed-D switchboards.
How much panel space is required for the QO240?
This 2-pole miniature circuit breaker requires two standard 3/4-inch spaces, taking up a total width of 1.5 inches on the distribution bus.
What is the recommended tightening torque for the box lugs?
The box lug terminals on the QO240 should be torqued to 44.3 inch-pounds (5 N.m). This specification applies to both copper and aluminum conductors ranging from 8 AWG to 2 AWG.
How does the Visi-Trip indicator work on this breaker?
The patented Visi-Trip feature is a highly visible red flag that snaps into the breaker window when it trips due to a fault. This provides instant visual confirmation of the tripped circuit without needing to manually test each handle in the panel.
Is this breaker HACR rated for HVAC applications?
Yes. The QO240 carries a HACR rating, which means it is certified to provide safe overcurrent protection for heating, air conditioning, and refrigeration equipment with motor loads.
Does the QO240 have a common trip mechanism?
Yes. It features an internal common trip mechanism. If a short circuit or overload occurs on one leg of a 240V circuit, both poles will open simultaneously. This design prevents single-phasing, which can severely damage connected 240V motors and compressors.
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Shipping
Free Shipping Policy
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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We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
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Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
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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 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