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Siemens B120 Molded Case Circuit Breaker
- 20A
- 1 Pole
- Bolt-On
Siemens
B120
Molded Case Circuit Breaker
Brand
Siemens
SKU
B120
Quantity
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Siemens B120 - 20A 1 Pole Molded Case Circuit Breaker
New
Quantity
Quantity
Siemens B120 - 20A 1 Pole Molded Case Circuit Breaker
New
Quantity
| Brand | Siemens |
|---|---|
| Part Number | B120 |
| Series | BL |
| Amperage | 20A |
| Poles | 1 |
| 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 | 14-10 AWG (Cu), 12-10 AWG (Al) |
| Max Wire | 10 AWG |
| Min Wire | 14 AWG (Cu), 12 AWG (Al) |
| 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, Alarm Switch, Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, HACR, SWD, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, SWD Rated, Insta-Wire |
Sold out
Quantity
Siemens B120 - 20A 1 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
| Brand | Siemens |
|---|---|
| Part Number | B120-R |
| Series | BL |
| Amperage | 20A |
| Poles | 1 |
| 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 | 14-10 AWG (Cu), 12-10 AWG (Al) |
| Max Wire | 10 AWG |
| Min Wire | 14 AWG (Cu), 12 AWG (Al) |
| 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, Alarm Switch, Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, HACR, SWD, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, SWD Rated, Insta-Wire |
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Description
Built for commercial applications, the Siemens B120 is a 1-pole, 20A molded case circuit breaker. It utilizes thermal-magnetic trip technology to provide dependable LI overcurrent protection. This BL-type bolt-on MCCB mounts into Siemens P1 through P5 panelboards. It serves as a reliable substitute for legacy BAB1020, TEB111020, and BDB120 breakers. Rated for 10 kAIC at 120/240VAC, the unit features Insta-Wire connectors for faster installation. It is fully HACR and SWD rated.Specifications
| Brand | Siemens |
|---|---|
| Part Number | B120 |
| Series | BL |
| Amperage | 20A |
| Poles | 1 |
| 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 | 14-10 AWG (Cu), 12-10 AWG (Al) |
| Max Wire | 10 AWG |
| Min Wire | 14 AWG (Cu), 12 AWG (Al) |
| 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, Alarm Switch, Padlock Attachment |
|---|---|
| Standards | CSA C22.2 No. 5, HACR, SWD, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, SWD Rated, Insta-Wire |
Product FAQs
7 answersWhat panelboards are compatible with the Siemens B120?
This breaker is approved for use in Siemens P1, P2, P3, P4, and P5 panelboards [1.2.1]. It also serves as a direct replacement for legacy ITE bolt-on panelboards that accept BL-frame circuit breakers.
Can the B120 be used to control fluorescent lighting circuits?
Yes, it is SWD (Switching Duty) rated, which means the breaker is certified to be used as a regular switch for 120V fluorescent lighting loads without degrading the internal contacts.
Is the B120 certified for HVAC applications?
Yes, this breaker is HACR rated. It is evaluated and approved for the unique electrical demands of heating, air conditioning, and refrigeration equipment.
Are Siemens BL and QP breakers interchangeable?
No. The BL series (including the B120) utilizes a bolt-on mounting system for secure connections in commercial panels. The QP series is a plug-on breaker meant for residential load centers. You must match the breaker mounting style to your panel busbar.
Will a modern Siemens B120 replace an older ITE B120?
Yes. Siemens acquired ITE and maintained the BL series design. The current Siemens B120 is functionally identical and serves as a direct, interchangeable replacement for legacy ITE B120 bolt-on breakers.
What type of protection does the LI trip function provide?
The B120 features fixed thermal and fixed magnetic (LI) trip units. The thermal element offers long-time protection against sustained overloads, while the magnetic element provides instantaneous protection to safely clear short circuits.
Can I use aluminum wiring with this breaker?
Yes, the B120 terminal lugs are approved for dual-rated (CU/AL) conductors. Ensure you use 14 to 10 AWG for copper or 12 to 10 AWG for aluminum wire, and tighten the terminal to the manufacturer specified torque.
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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