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Square D QOB145 Miniature Circuit Breaker
- 45A
- 1 Pole
- Bolt-On
Square D
QOB145
Miniature Circuit Breaker
Brand
Square D
SKU
QOB145
Quantity
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Square D QOB145 - 45A 1 Pole Miniature Circuit Breaker
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Description
Part of the renowned QO family, the Square D QOB145 is a 45A, 1-pole miniature circuit breaker. It delivers reliable overcurrent and short-circuit protection for commercial and industrial electrical systems. Designed for a secure fit, this breaker bolts into Square D NQ and NQOD panelboards. The bolt-on mounting style guarantees a tight connection that resists loosening over time in high-vibration environments.Specifications
| Brand | Square D |
|---|---|
| Series | QOB |
| Amperage | 45A |
| Poles | 1 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC, 48VDC |
| Phase | 1 |
| AIC Rating | 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 | Shunt Trip, Auxiliary Switch, Alarm Switch |
|---|---|
| Accessories | Load Side Lugs Included |
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
Product FAQs
5 answersCan I install the QOB145 in a standard QO load center?
No. The QOB145 is a bolt-on circuit breaker designed for NQ and NQOD panelboards. Standard QO load centers require plug-on QO breakers, not bolt-on QOB types.
What is the recommended lug torque for the QOB145?
The box lugs on the QOB145 should be torqued to 44.3 lb-in (5 N.m) for 8-2 AWG aluminum or copper wire.
Does the QOB145 feature a Visi-Trip indicator?
Yes. Like most QO and QOB breakers, it includes a Visi-Trip indicator that displays a highly visible red flag when the breaker has tripped, making it easy to identify the faulted circuit in a crowded panel.
Is there a version of this 45A 1-pole breaker with a higher interrupting rating?
Yes. While the standard QOB145 is rated for 10kAIC at 120/240VAC, you can use the QHB145 for applications requiring a 65kAIC rating.
Is a 45A 1-pole breaker a standard size?
While 45A is an uncommon amperage for a 1-pole breaker, it is a standard factory rating manufactured by Square D for specific equipment loads that require exactly 45 amps of overcurrent protection on a single 120V leg.
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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