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Free Shipping Over $99
Free Shipping Over $99
Free Shipping Over $99
Square D QO390 Miniature Circuit Breaker
- 90A
- 3 Pole
- Plug-On
Square D
QO390
Miniature Circuit Breaker
Brand
Square D
SKU
QO390
Quantity
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Square D QO390 - 90A 3 Pole Miniature Circuit Breaker
New
Quantity
Quantity
Square D QO390 - 90A 3 Pole Miniature Circuit Breaker
New
Quantity
| Brand | Square D |
|---|---|
| Part Number | QO390 |
| Series | QO |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | QO Load Centers, NQ Panelboards, Speed-D Switchboards |
| Wire Gauge | 4 AWG - 2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment, Handle Lock |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip |
Sold out
Quantity
Square D QO390 - 90A 3 Pole Miniature Circuit Breaker
Re-Certified
Quantity
| Brand | Square D |
|---|---|
| Part Number | QO390-R |
| Series | QO |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | QO Load Centers, NQ Panelboards, Speed-D Switchboards |
| Wire Gauge | 4 AWG - 2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment, Handle Lock |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip |
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Description
Designed for commercial and industrial environments, the QO390 delivers robust thermal-magnetic protection for three-phase systems. It mounts into standard Square D QO load centers, NQ panelboards, and Speed-D switchboards without requiring special tools. Featuring the signature Visi-Trip indicator, this 10kAIC rated component allows maintenance personnel to quickly identify tripped circuits, minimizing downtime in critical facility operations.Specifications
| Brand | Square D |
|---|---|
| Part Number | QO390 |
| Series | QO |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Plug-On |
| Voltage | 240VAC, 120/240VAC, 48VDC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC, 10kA @ 120/240VAC, 5kA @ 48VDC |
| Terminal Type | Box Lugs |
|---|---|
| For Use With | QO Load Centers, NQ Panelboards, Speed-D Switchboards |
| Wire Gauge | 4 AWG - 2/0 AWG (Al/Cu) |
| Max Wire | 2/0 AWG |
| Min Wire | 4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment, Handle Lock |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, Common Trip |
Product FAQs
5 answersCan I install the QO390 in a Square D Homeline load center?
No. Homeline load centers only accept HOM series circuit breakers, which are built on a 1 inch wide format. The QO390 uses a 3/4 inch per pole design and is physically incompatible.
What is the catalog number for the bolt-on equivalent of this breaker?
If your installation requires bolt-on connections instead of a plug-on mount, you will need to source catalog number QOB390.
Does the QO390 include the Square D Visi-Trip indicator?
Yes, it is equipped with the Visi-Trip feature. When the breaker trips due to an overcurrent or short circuit, a highly visible red flag appears in the indicator window for quick identification.
Is the QO390 approved for HVAC equipment?
Yes, this breaker is HACR rated. It is suitable for protecting heating, air conditioning, and refrigeration equipment circuits.
Will all three poles open simultaneously during a fault?
Yes. The QO390 features an internal common trip mechanism. If an overcurrent or short circuit occurs on any single pole, it forces all three poles to open simultaneously, preventing single-phasing of your connected equipment.
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Shipping
Free Shipping Policy
Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
Same Day Shipping
We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
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Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
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