Part of the QO family, the Square D QOB3125VH is a thermal-magnetic miniature circuit breaker built for commercial and industrial electrical systems. It delivers reliable overcurrent protection for heavy-duty branch circuits. This 125-amp breaker installs securely into Square D NQ and NQOD panelboards using a bolt-on mounting style. It requires six panel spaces and accepts 4 AWG to 300 kcmil wiring. Rated for 22 kAIC at 120/240V, it features a Visi-Trip indicator for quick fault detection.
Specifications
Brand
Square D
Series
QOB
Part Number
QOB3125VH
Amperage
125A
Voltage
120VAC, 240VAC, 120/240VAC
Poles
3
Phase
3
AIC Rating
22kA @ 120VAC, 22kA @ 240VAC, 22kA @ 120/240VAC
Mounting Style
Bolt-On
Terminal Type
Box Lugs
For Use With
Square D NQ Panelboards, Square D NQOD Panelboards
Trip Technology
Thermal Magnetic
Trip Function Code
LI
Trip Function
Long-Time, Instantaneous
Trip Adjustability
Fixed
Wire Gauge
4 AWG - 300 kcmil (Al/Cu)
Max Wire
300 kcmil
Min Wire
4 AWG
Available Options
Shunt Trip, Auxiliary Switch, Alarm Switch
Accessories
Load Side Lugs Included
Standards
HACR, RoHS, UL 489
Approval
CSA, UL
Temp Rating
40C
Construction Features
Visual Trip Indicator, HACR Rated, High Interrupting Capacity
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When shopping with SuperBreakers, you’ll have peace of mind knowing that every single item you purchase includes a 60 day warranty, free of charge. Why such confidence? Because only the highest quality electrical parts have a place on our shelves, and we stand by every single one we sell.
If anything goes wrong with your item that is not a result of misuse or normal wear and tear, we’ll gladly replace it at no cost to you.
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4.9
Rated 4.9 out of 5 stars
Based on 188 reviews
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Total 5 star reviews: 181
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Total 4 star reviews: 6
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Total 3 star reviews: 0
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Total 2 star reviews: 0
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Total 1 star reviews: 1
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.