Square D Q221150AB Molded Case Circuit Breaker
- 150A
- 2 Pole
- I-Line
Quantity
Square D Q221150AB - 150A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Built for commercial and industrial power distribution, the Q221150AB is a legacy 2-pole, 150A molded case circuit breaker from Square D. It delivers thermal-magnetic protection with a 10kAIC rating at 120/240VAC. Featuring an I-Line mounting style with an AB phase connection, this breaker easily installs into compatible Square D I-Line panelboards. While the original Q2 series is discontinued, this unit maintains existing systems and is officially replaced by the modern PowerPact QBA22150.Specifications
| Brand | Square D |
|---|---|
| Series | Q2 |
| Amperage | 150A |
| Poles | 2 |
| Mounting Style | I-Line |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | Q221 |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards |
| Wire Gauge | 4 AWG - 300 kcmil (Al/Cu) |
| Max Wire | 300 kcmil |
| Min Wire | 4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Fixed Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Load Side Lugs Included |
| Standards | CSA C22.2 No. 5, NEMA AB 1, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, HACR Rated |
Product FAQs
6 answersWhat does the "AB" suffix indicate on the Q221150AB?
The "AB" suffix specifies the phase connection for the breaker. It is configured with jaws that connect exclusively to the A and B phases of a Square D I-Line panelboard bus.
What is the modern replacement for the legacy Q221150AB circuit breaker?
The original Q2 series is discontinued. The official modern replacement for this 150A, 2-pole breaker is the Square D PowerPact Q-Frame, specifically catalog number QBA22150.
How does the I-Line connection on the Q221150AB work?
The I-Line mounting style uses plug-on jaws that grip the panelboard bus bars directly. This design eliminates the need for mounting screws on the bus, allowing for faster installation and flexible breaker positioning within compatible Square D I-Line panelboards.
How can I tell if the Q221150AB has tripped?
This breaker features the Square D Visi-Trip indicator. When a fault causes the breaker to trip, the handle moves to a center position and a bright red flag appears in the indicator window, making it easy to spot in a crowded panel.
Is this breaker rated for HVAC equipment?
Yes, the Q221150AB is HACR rated. It is tested and approved to handle the inrush currents and operational demands of heating, air conditioning, and refrigeration equipment.
Can the trip unit on the Q221150AB be swapped for a different amperage?
No, this breaker features a non-interchangeable thermal-magnetic trip unit. The 150A trip elements are fixed internally and cannot be removed or swapped in the field.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 8 reviews.
- MEMichael E.Verified BuyerReviewingSquare D Q221150AC - 150A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars4/28/26breaker purchase
delivered on time and quality was as advertised
- MWmakalita w.Verified BuyerReviewingSquare D Q232150 - 150A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/18/26Prompt service.
Well packaged
- GSGreg S.Verified BuyerReviewingSquare D Q232200 - 200A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/29/25Great Job
Whenever I need a breaker and my local distributor can't handle or get what I need, Superbreakers has always come through for us.
- AWAllen W.ReviewingSquare D Q232175 - 175A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars6/17/22Great condition
The breakers were in great condition. The serve was also great.
- JCJim C.ReviewingSquare D Q232200 - 200A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars1/13/22Great Service
My order was received fast. The packaging was perfect. The quality of the product was what was expected.