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Siemens Q2125B Molded Case Circuit Breaker
- 125A
- 2 Pole
- Plug-On
Siemens
Q2125B
Molded Case Circuit Breaker
Brand
Siemens
SKU
Q2125B
Quantity
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Siemens Q2125B - 125A 2 Pole Molded Case Circuit Breaker
New
Quantity
Quantity
Siemens Q2125B - 125A 2 Pole Molded Case Circuit Breaker
New
Quantity
| Brand | Siemens |
|---|---|
| Part Number | Q2125B |
| Series | Q |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | Q |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens Load Centers |
| Wire Gauge | 8 AWG - 2/0 AWG (Cu/Al) |
| Max Wire | 2/0 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Common Trip, Insta-Wire, Reverse Feed |
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Quantity
Siemens Q2125B - 125A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
| Brand | Siemens |
|---|---|
| Part Number | Q2125B-R |
| Series | Q |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | Q |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens Load Centers |
| Wire Gauge | 8 AWG - 2/0 AWG (Cu/Al) |
| Max Wire | 2/0 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Common Trip, Insta-Wire, Reverse Feed |
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Description
Built for versatility, the Siemens Q2125B provides 125A of thermal-magnetic protection for 120/240VAC systems. The two-pole plug-on unit requires two panel spaces and mounts into standard Siemens load centers. It is approved for reverse feed applications and serves as a functional substitute for the standard Q2125 breaker. This model features Insta-Wire connections to speed up wiring. It delivers a 10kAIC interrupting rating, common trip functionality, and is HACR rated for HVAC loads.Specifications
| Brand | Siemens |
|---|---|
| Part Number | Q2125B |
| Series | Q |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Plug-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | Q |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens Load Centers |
| Wire Gauge | 8 AWG - 2/0 AWG (Cu/Al) |
| Max Wire | 2/0 AWG |
| Min Wire | 8 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed |
| Available Options | Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, UL 489, HACR |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Common Trip, Insta-Wire, Reverse Feed |
Product FAQs
6 answersHow many panel spaces does the Q2125B require?
This two-pole plug-on breaker requires two standard panel spaces in a compatible Siemens load center.
Can the Q2125B replace a standard Q2125 breaker?
Yes, the Q2125B serves as a functional substitute for the standard Q2125 breaker. It also features Insta-Wire connections to speed up the wiring process.
Is the Q2125B approved for reverse feed applications?
Yes, this breaker is approved for reverse feed applications. When used as a back-fed main breaker, it must be secured with an approved panel hold-down kit as required by the National Electrical Code.
Is this breaker HACR rated?
Yes, the Q2125B carries an HACR rating, making it suitable for heating, air conditioning, and refrigeration motor loads.
What panels accept the Q2125B breaker?
It mounts into standard Siemens load centers that accept QP family plug-on breakers. Always consult your panel label or wiring diagram to confirm acceptance of 125A branch or main breakers.
Does the Q2125B feature a common trip mechanism?
Yes, this two-pole breaker features common trip functionality, ensuring that an overload or short circuit on either leg will trip both poles simultaneously.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 47 reviews.
Reviews Summary
Generated by AI from 91 most recent customer reviews
Last updated 8/1/25
Customers say these circuit breakers arrive quickly and match their specifications perfectly. Many reviews mention success finding hard-to-locate specialty breakers through this supplier. Common feedback includes praise for the accurate product descriptions, reliable shipping, and competitive pricing. While some note occasional stock limitations, users consistently report the breakers fit and function as intended.
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Rating
47 reviews
- CGCrocefissa G.Verified BuyerReviewingSiemens Q115 - 15A 1 Pole Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars9/18/26Quick delivery and great price.
The circuit breakers are at a great cost.
- JBJason B.Verified BuyerReviewingSiemens Q2150B - 150A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/18/26Great experience
The product was exactly what I needed and it arrived on time.
- DQDon Q.Verified BuyerReviewingSiemens Q3100 - 100A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/14/26Siemens breaker
Great customer experience, great prices and fast shipping... Definitely will be buying her again.
- CSChristopher S.Verified BuyerRated 5 out of 5 stars8/12/26Siemens 60
Perfect new condition
- GSGeorge S.Verified BuyerReviewingSiemens Q2150B - 150A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/4/26Great service
Every time I call or go online you have the parts I'm looking for.