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Square D Q2M3125MB Molded Case Circuit Breaker
- 125A
- 3 Pole
- Bolt-On
Square D
Q2M3125MB
Molded Case Circuit Breaker
Brand
Square D
SKU
Q2M3125MB
Quantity
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Square D Q2M3125MB - 125A 3 Pole Molded Case Circuit Breaker
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125A 3 Pole Molded Case Circuit Breaker
125A 3 Pole Molded Case Circuit Breaker
125A 3 Pole Molded Case Circuit Breaker
Description
Supplying 125A of thermal-magnetic protection, the Square D Q2M3125MB is a three-phase molded case circuit breaker engineered for demanding commercial applications. It utilizes fixed thermal and magnetic trip elements for consistent performance. The breaker bolts securely into Square D switchboards and panelboards. Facilities upgrading their equipment can use the QDL32125 as a modern replacement. Rated for 10kAIC at 240VAC, it includes a Visi-Trip indicator to quickly identify tripped circuits.Specifications
| Brand | Square D |
|---|---|
| Part Number | Q2M3125MB-R |
| Series | Q2 |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC |
| Phase | 3 |
| AIC Rating | 10kA @ 240VAC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Square D Panelboards, Switchboards |
| 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, Mounting Hardware |
| Standards | CSA C22.2 No. 5, UL 489, NEMA AB 1 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Visual Trip Indicator, Main Breaker |
Product FAQs
4 answersWhat type of panels accept the Q2M3125MB?
This breaker is designed specifically to bolt into legacy Square D panelboards and switchboards. It is commonly used as a main breaker or sub-feed in these commercial enclosures.
What is the modern replacement for the legacy Q2M3125MB?
The Q2 series is a legacy frame. Facilities upgrading their equipment can use the Square D PowerPact QDL32125 as a modern replacement.
Does this breaker include a visual trip indicator?
Yes, it is equipped with a Visi-Trip indicator. This feature provides a clear visual cue when the breaker has tripped, making it easier to identify faults in a crowded panelboard.
Is the Q2M3125MB rated for 100 percent continuous duty?
No, like most standard molded case circuit breakers, it carries an 80 percent continuous current rating. Continuous loads on this 125A breaker should not exceed 100 amps.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 8 reviews.
Total 5 star reviews: 8 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
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Rating
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.