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Square D QOB345-1021 QOB3451021 - 45A 3 Pole Miniature Circuit Breaker
- 45A
- 3 Pole
- Bolt-On
Square D
QOB345-1021
QOB3451021 - 45A 3 Pole Miniature Circuit Breaker
Brand
Square D
SKU
QOB345-1021
Quantity
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Square D QOB3451021 - 45A 3 Pole Miniature Circuit Breaker
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Description
Featuring remote tripping capabilities, the QOB345-1021 includes a factory-installed shunt trip mechanism. This 45-amp, three-pole device is designed for commercial environments requiring automated control. The unit utilizes a robust bolt-on connection for maximum stability. It is fully compatible with Square D NQ and NQOD panelboards. Alongside the shunt trip, it retains the standard Visi-Trip indicator for quick fault identification, providing a 10kAIC rating at 240VAC.Specifications
| Brand | Square D |
|---|---|
| Part Number | QOB345-1021 |
| 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), Load Side Lugs Included |
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator |
Product FAQs
7 answersWhat does the -1021 suffix indicate on the QOB345-1021?
The -1021 suffix signifies that the breaker comes with a factory-installed 120/208/240V AC shunt trip. This accessory allows the breaker to be tripped remotely, which is often required for emergency shutdown or automated control systems.
Which panelboards accept the QOB345-1021 circuit breaker?
This breaker is specifically designed for bolt-on installation in Square D NQ and NQOD panelboards. It is not compatible with standard QO load centers, which require plug-on breakers.
How is the QOB345-1021 secured to the panelboard?
It uses a bolt-on mounting style. This bolted connection fastens directly to the panelboard bus, providing a secure and reliable contact that is ideal for commercial or industrial environments prone to vibration.
How can I tell if the QOB345-1021 has tripped?
This breaker features the Square D Visi-Trip indicator. When the breaker trips due to an overload or short circuit, a highly visible red indicator appears in the window, allowing for quick identification of the faulted circuit.
How does the thermal-magnetic trip mechanism operate on this breaker?
The thermal-magnetic system provides two types of protection. The thermal component provides a long-time delay to handle mild, temporary overloads, while the magnetic component provides an instantaneous trip to quickly clear severe short circuits.
Is the QOB345-1021 interchangeable with a standard QO345?
No. While both are 45A, 3-pole breakers, the QOB345-1021 is a bolt-on breaker for NQ and NQOD panelboards and includes a shunt trip accessory. A standard QO345 is a plug-on breaker without a shunt trip and is intended for QO load centers.
Is the QOB345-1021 suitable for HVAC applications?
Yes, this breaker is HACR rated, meaning it is approved for use with compatible heating, air conditioning, and refrigeration equipment.
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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