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Square D QO345-1021 QO3451021 - 45A 3 Pole Miniature Circuit Breaker
- 45A
- 3 Pole
- Plug-On
Square D
QO345-1021
QO3451021 - 45A 3 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QO345-1021
Quantity
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Square D QO3451021 - 45A 3 Pole Miniature Circuit Breaker
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Description
Built to support remote shutdown operations, the Square D QO345-1021 includes a factory-installed shunt trip rated for 120/208/240VAC. This 3-pole, 45A plug-on circuit breaker installs into QO load centers, NQ, and NQOD panelboards, making it ideal for commercial and industrial control schemes. Delivering a 10 kAIC interrupting rating at 240VAC, it combines standard thermal-magnetic protection with the convenience of the Visi-Trip indicator for rapid fault detection.Specifications
| Brand | Square D |
|---|---|
| Part Number | QO345-1021 |
| Series | QO |
| Amperage | 45A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Frame Type | QO |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | QO Load Centers, NQ Panelboards, NQOD Panelboards |
| Wire Gauge | 8 AWG - 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 (120/208/240VAC) |
| Standards | CSA C22.2 No. 5, UL 489, RoHS |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip |
Product FAQs
7 answersWhat panels are compatible with the QO345-1021 circuit breaker?
This 3-pole breaker requires three spaces in a compatible Square D QO load center, NQ panelboard, or NQOD panelboard.
What does the -1021 suffix mean on this Square D QO breaker?
The -1021 suffix indicates that the breaker includes a factory-installed 120/240VAC shunt trip accessory, allowing the breaker to be tripped remotely via an external control signal.
What wire gauge is accepted by the box lugs on the QO345-1021?
The box lug terminals accept 8 AWG to 2 AWG wire. Ensure you apply the correct torque specifications listed on the breaker label when terminating either aluminum or copper conductors.
How does the QO345-1021 install into the panel?
It features a standard plug-on mounting design that snaps directly into the busbar of compatible QO, NQ, or NQOD panels, eliminating the need for bolted connections.
Can the QO345-1021 be used in DC applications?
Yes, in addition to its AC ratings, this breaker is rated for 48VDC applications with a 5kA interrupting capacity, making it suitable for specific low-voltage control or battery circuits.
What type of trip protection does this breaker provide?
It features fixed thermal-magnetic trip technology. The thermal element provides long-time protection against gradual overloads, while the magnetic element delivers instantaneous protection against severe short circuits.
Does this breaker include a Visi-Trip indicator?
Yes, it features the signature Square D Visi-Trip visual indicator. When the breaker trips, the handle snaps to a midpoint position and a highly visible red flag appears, allowing for rapid fault detection in crowded panels.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 286 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
286 reviews
- RBRobert B.Verified BuyerReviewingSquare D QO120 - 20A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars10/5/26Square D Q0120-20A circuit breaker
This device was delivered on time as advertised and it was in excellent condition. The installation process was simple and straightforward, and the unit worked perfectly when connected to the electric circuit.
I am completely satisfied and will utilize this component resource for my future electrical needs.
- 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