Square D QOB390VH1021 Miniature Circuit Breaker
- 90A
- 3 Pole
- Bolt-On
Quantity
Square D QOB390VH1021 - 90A 3 Pole Miniature Circuit Breaker
New
Quantity
Description
Providing remote tripping capabilities, this 90-amp commercial breaker includes a factory-installed shunt trip accessory for emergency shutdown systems. It mounts firmly into Square D NQ and NQOD panelboards, ensuring a secure connection for three-phase applications. Rated for 22kAIC at 240V, it handles higher fault currents than standard models while offering thermal-magnetic protection. The unit includes the Visi-Trip indicator and is HACR rated for heating and cooling equipment.Specifications
| Brand | Square D |
|---|---|
| Series | QOB |
| Amperage | 90A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 120/240VAC |
| Phase | 3 |
| AIC Rating | 22kA @ 240VAC, 22kA @ 120/240VAC |
| Frame Type | QOB |
|---|---|
| Terminal Type | Box Lugs |
| For Use With | NQ Panelboards, NQOD Panelboards |
| 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 | Auxiliary Switch, Alarm Switch, Padlock Attachment, Handle Tie, Handle Lock |
|---|---|
| Accessories | Shunt Trip |
| Standards | CSA C22.2 No. 5, HACR, RoHS, UL 489 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, High Interrupting Capacity, Common Trip, Trip-Free Mechanism, Quick-Make/Quick-Break |
Product FAQs
7 answersWhat panelboards are compatible with the QOB390VH1021?
This bolt-on miniature circuit breaker is designed specifically for use in Square D NQ and NQOD series panelboards.
How many panel spaces does the QOB390VH1021 require?
It requires four pole spaces in the panelboard. The 3-pole breaker itself occupies three spaces, and the factory-installed shunt trip accessory requires one additional space.
What does the 1021 suffix indicate on this Square D breaker?
The 1021 suffix means this breaker comes equipped with a factory-installed 120/208/240VAC shunt trip accessory, which allows the circuit to be opened remotely for emergency shutdown or control schemes.
What does the VH designation mean in the QOB390VH1021 part number?
The VH indicates a high interrupting rating. While standard QOB breakers are typically rated at 10kAIC, this model handles up to 22kAIC at 120/240VAC, providing enhanced protection against higher fault currents.
How can I tell if this breaker has tripped?
It features Square D's Visi-Trip indicator. When the breaker trips, the handle snaps to a midpoint position and a highly visible red flag appears in the window, allowing for rapid fault identification in a crowded panel.
How does this breaker connect to the panel bus?
It utilizes a bolt-on connection, meaning it fastens directly to the panelboard bus bar with screws. This provides a secure, vibration-resistant connection ideal for commercial and industrial environments.
Can I use this to replace a standard QOB390?
No, they are not direct physical drop-ins. While both are 90A 3-pole breakers, the QOB390VH1021 requires four panel spaces due to the factory-installed shunt trip, whereas a standard QOB390 only requires three spaces.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 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