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Siemens B2125 Molded Case Circuit Breaker
- 125A
- 2 Pole
- Bolt-On
Siemens
B2125
Molded Case Circuit Breaker
Brand
Siemens
SKU
B2125
Quantity
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Siemens B2125 - 125A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
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Siemens B2125 - 125A 2 Pole Molded Case Circuit Breaker
New
Quantity
| Brand | Siemens |
|---|---|
| Part Number | B2125 |
| Series | BL |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | B |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3, P4, P5 Panelboards |
| Wire Gauge | 2-1/0 AWG (Cu), 1/0-2/0 AWG (Al) |
| Max Wire | 1/0 AWG (Cu), 2/0 AWG (Al) |
| Min Wire | 2 AWG (Cu), 1/0 AWG (Al) |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR Rated |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
Sold out
Quantity
Siemens B2125 - 125A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
| Brand | Siemens |
|---|---|
| Part Number | B2125-R |
| Series | BL |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | B |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3, P4, P5 Panelboards |
| Wire Gauge | 2-1/0 AWG (Cu), 1/0-2/0 AWG (Al) |
| Max Wire | 1/0 AWG (Cu), 2/0 AWG (Al) |
| Min Wire | 2 AWG (Cu), 1/0 AWG (Al) |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR Rated |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
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Description
Engineered for robust distribution, the Siemens B2125 is a 2-pole, 125A molded case circuit breaker. It operates safely on 120/240VAC systems, providing a 10kAIC rating for commercial facilities. The bolt-on mounting guarantees a stable connection inside compatible enclosures. It installs easily into Siemens P1 through P5 panelboards and can substitute for BAB2125 or QOB2125 models. Thermal-magnetic trip technology ensures accurate response to overcurrents.Specifications
| Brand | Siemens |
|---|---|
| Part Number | B2125-R |
| Series | BL |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | B |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3, P4, P5 Panelboards |
| Wire Gauge | 2-1/0 AWG (Cu), 1/0-2/0 AWG (Al) |
| Max Wire | 1/0 AWG (Cu), 2/0 AWG (Al) |
| Min Wire | 2 AWG (Cu), 1/0 AWG (Al) |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Shunt Trip, Auxiliary Switch, Alarm Switch, Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR Rated |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
Product FAQs
5 answersCan I install this breaker in a standard Siemens residential load center?
No. The B2125 is a BL-frame bolt-on breaker designed strictly for commercial Siemens P1 through P5 panelboards. Standard residential load centers require plug-in style breakers, such as the QP series.
What is the plug-in equivalent of the B2125?
If you need a 125-amp, two-pole plug-in breaker for a standard Siemens EQ or Ultimate residential load center, you will need the QP series equivalent, which is catalog number Q2125.
Does the B2125 replace older ITE or Gould breakers?
Yes. Siemens acquired the electrical divisions of both ITE and Gould. This breaker is a direct, UL-listed replacement for older ITE and Gould BL-frame breakers with the identical B2125 catalog number.
Is the Siemens B2125 HACR rated?
Yes, it carries a HACR rating, making it approved for use with heating, air conditioning, and refrigeration equipment that require this specific overcurrent protection.
How much mounting space does this breaker require in the panelboard?
As a standard BL-frame breaker, it requires one inch of panel space per pole. Therefore, this two-pole breaker will occupy two inches of continuous space on the busbar.
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Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 35 reviews.
Total 5 star reviews: 34 Total 4 star reviews: 1 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
Reviews Summary
Generated by AI from 66 most recent customer reviews
Last updated 8/15/25
Customers say these circuit breakers meet their specifications and perform as expected. Many reviews highlight the quick delivery times and competitive pricing. Frequent comments address the reliable product quality and ease of installation. The ordering process receives praise for its simplicity, with users noting consistent product availability.
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Rating
35 reviews
- TSTom S.Verified BuyerReviewingSiemens B3100 3 Pole Circuit BreakerI recommend this productRated 5 out of 5 stars8/3/26Superbreakers is our go to!
Great prices, great service and quick delivery.
- MGMaggie G.Verified BuyerReviewingSiemens B250 - 50A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars6/24/26Great Service
Came in great condition and in an incredibly timely manner. Will continue superbreakers for all of my orders in the future!
- DBDonnie B.Verified BuyerReviewingSiemens B115 - 15A 1 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars6/11/26New Breaker
Awesome breaker & Superbreakers is a awesome company!
- BLBrian L.Verified BuyerReviewingSiemens B120 - 20A 1 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars6/4/26Brian
Works great
- JFJoseph F.Verified BuyerReviewingSiemens B120 - 20A 1 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/23/26Great value
It was a great value