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Square D QOB3451021 Miniature Circuit Breaker
- 45A
- 3 Pole
- Bolt-On
Square D
QOB3451021
Miniature Circuit Breaker
Brand
Square D
SKU
QOB3451021
Quantity
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Square D QOB3451021 - 45A 3 Pole Miniature Circuit Breaker
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Description
Engineered for commercial applications, the Square D QOB3451021 delivers 45A of reliable thermal-magnetic protection. This 3-pole miniature circuit breaker handles demanding electrical distribution needs. This device installs into Square D NQ and NQOD panelboards. The bolted connection ensures stable performance in environments subject to vibration. It features a factory-installed 120/208/240V AC shunt trip for remote tripping, plus the Visi-Trip indicator for quick status identification.Specifications
| Brand | Square D |
|---|---|
| Series | QOB |
| Amperage | 45A |
| 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 |
| Frame Type | QOB |
|---|---|
| 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, Padlock Attachment |
|---|---|
| Accessories | Shunt Trip (Factory Installed) |
| Standards | CSA C22.2 No. 5, UL 489, HACR, RoHS |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, HACR Rated |
Product FAQs
6 answersWhat panelboards are compatible with the QOB3451021?
This bolt-on circuit breaker is designed for use in Square D NQ and NQOD panelboards. It cannot be used in standard QO plug-on load centers.
What does the 1021 suffix indicate on this breaker?
The 1021 suffix signifies a factory-installed shunt trip accessory. This allows the breaker to be opened remotely using a 120VAC, 208VAC, or 240VAC control signal.
How many panel spaces does the QOB3451021 require?
Due to the factory-installed shunt trip module, this 3-pole breaker requires four panel spaces for installation instead of the standard three.
What is the control voltage required to operate the shunt trip?
The integrated shunt trip mechanism requires a 120VAC, 208VAC, or 240VAC control voltage signal to remotely open the circuit.
What type of wire is compatible with the terminals on this breaker?
The box lugs are rated for both aluminum and copper conductors, accepting wire sizes from 8 AWG to 2 AWG.
How does the Visi-Trip indicator function on this breaker?
The Visi-Trip feature displays a highly visible red flag in the breaker window when it trips due to an overcurrent or short circuit event, allowing for rapid fault identification in crowded panels.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 205 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
205 reviews
- 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.
- RKRyan K.Verified BuyerReviewingSquare D QOB230VH - 30A 2 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars7/1/26Awesome
Worked great