Square D QOB350VH-1021 QOB350VH1021 - 50A 3 Pole Miniature Circuit Breaker
- 50A
- 3 Pole
- Bolt-On
Quantity
Square D QOB350VH1021 - 50A 3 Pole Miniature Circuit Breaker
New
Quantity
Description
Engineered for commercial power distribution, the Square D QOB350VH-1021 is a 50A miniature breaker featuring a factory-installed 120/240VAC shunt trip for remote shutdown capabilities. This bolt-on breaker installs into Square D NQ and NQOD panelboards, providing a secure, vibration-resistant connection. The box lugs accept 8-2 AWG wiring. Delivering a 22kAIC interrupt rating at 120/240VAC, it provides robust protection and includes a Visi-Trip indicator for rapid fault identification.Specifications
| Brand | Square D |
|---|---|
| Series | QOB |
| Amperage | 50A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 120VAC, 240VAC, 120/240VAC |
| Phase | 3 |
| AIC Rating | 22kA @ 120VAC, 22kA @ 240VAC, 22kA @ 120/240VAC |
| 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 |
|---|---|
| Accessories | Shunt Trip (Factory Installed), Load Side Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5, HACR |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Visual Trip Indicator, High Interrupting Capacity |
Product FAQs
8 answersWhich panelboards are compatible with the QOB350VH-1021 circuit breaker?
This bolt-on circuit breaker is designed specifically for use in Square D NQ and NQOD series panelboards. It cannot be installed in standard QO load centers, which require plug-on breakers.
What does the 1021 suffix mean in the QOB350VH-1021 part number?
The 1021 suffix indicates that this breaker includes a factory-installed 120/208/240 VAC shunt trip accessory. This feature allows the breaker to be tripped remotely by applying a voltage signal from an external control circuit.
What does the VH designation indicate on this Square D breaker?
The VH indicates a Very High interrupting rating. While standard QOB breakers typically offer a 10kAIC rating, the QOB350VH-1021 provides an upgraded 22kAIC interrupting rating at 120/240VAC for systems with higher available fault currents.
How does the QOB350VH-1021 mount into a panelboard?
This QOB series breaker features a bolt-on mounting design. It bolts directly to the panelboard busbar, providing a secure and reliable mechanical connection that is preferred in commercial and industrial applications.
What wire sizes and materials are accepted by the terminals on this 50A breaker?
The box lugs on the QOB350VH-1021 are rated to accept 8 AWG to 2 AWG conductors. Both aluminum and copper wire can be used.
How does the thermal-magnetic trip unit function on this breaker?
The thermal-magnetic mechanism provides two types of protection. The thermal element offers long-time protection by tripping in response to sustained overloads, while the magnetic element provides instantaneous tripping when it detects high-current short circuits.
How is the factory-installed shunt trip wired during installation?
The shunt trip accessory features external leads that must be wired to a 120VAC, 208VAC, or 240VAC control circuit. When the control circuit is energized, it activates the internal coil to mechanically open the breaker contacts.
Does the QOB350VH-1021 feature a Visi-Trip indicator?
Yes, like most QO and QOB breakers, it includes a Visi-Trip visual indicator. When the breaker trips due to an overload or short circuit, a red indicator appears in the window to help quickly identify the tripped circuit.
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Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 206 reviews.
- KHKristopher H.Verified BuyerReviewingSquare D QOB120GFI - 20A GFCI Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/28/26Great Price!
Great price. Fast delivery. My local electric distributor wanted double for the same breaker, so it was a no brainer to order this one. Ordered another one since with the same great service.
- 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.