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Square D QO3501021 Miniature Circuit Breaker
- 50A
- 3 Pole
- Plug-On
Square D
QO3501021
Miniature Circuit Breaker
Brand
Square D
SKU
QO3501021
Quantity
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Square D QO3501021 - 50A 3 Pole Miniature Circuit Breaker
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Description
Providing advanced control for commercial systems, this 50A miniature circuit breaker includes a factory-installed 120/208/240VAC shunt trip. This allows the breaker to be tripped from a remote location using a separate voltage signal. The three-pole device requires four panel spaces and utilizes a plug-on connection to install into Square D QO load centers and NQ panelboards. Rated for 10kAIC at 240VAC, it features thermal-magnetic protection and the signature Visi-Trip indicator.Specifications
| Brand | Square D |
|---|---|
| Part Number | QO350-1021 |
| Series | QO |
| Amperage | 50A |
| 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 |
| Wire Gauge | 8-2 AWG (Cu/Al) |
| Max Wire | 2 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Padlock Attachment |
|---|---|
| Accessories | Shunt Trip |
| Standards | CSA C22.2 No. 5, HACR, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, HACR Rated |
Product FAQs
5 answersWhat does the 1021 suffix in the QO3501021 part number indicate?
The -1021 suffix means this circuit breaker features a factory-installed 120/208/240VAC shunt trip. This allows the breaker to be tripped remotely via a separate control voltage signal.
How many panel spaces does the QO3501021 require?
This unit requires 4 full spaces in a Square D QO load center or NQ panelboard. The standard 3-pole breaker occupies three spaces, while the factory-installed shunt trip module requires one additional pole space.
Is there a bolt-on version of this breaker available?
Yes, if your NQ panelboard requires a bolt-on connection, the direct equivalent is the QOB3501021. It features the same 50A rating, 3-pole configuration, and factory-installed shunt trip, but utilizes bolt-on mounting.
How does the shunt trip module affect standard breaker protection?
The shunt trip does not interfere with the breaker's standard thermal-magnetic protection against overloads and short circuits. It simply provides an additional way to manually or automatically open the circuit from a remote location.
How is the shunt trip accessory wired?
The factory-installed shunt trip features its own dedicated terminals for control wiring. You must connect these to a separate 120VAC to 240VAC control power source. Applying the required control voltage will instantly open the breaker contacts.
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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