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Siemens BQ2B040 Molded Case Circuit Breaker
- 40A
- 2 Pole
- Bolt-On
Siemens
BQ2B040
Molded Case Circuit Breaker
Brand
Siemens
SKU
BQ2B040
Quantity
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Siemens BQ2B040 - 40A 2 Pole Molded Case Circuit Breaker
New
Quantity
Quantity
Siemens BQ2B040 - 40A 2 Pole Molded Case Circuit Breaker
New
Quantity
| Brand | Siemens |
|---|---|
| Part Number | BQ2B040 |
| Series | BQ |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | BQ |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens Panelboards (P1, P2, P3) |
| Wire Gauge | 14-6 AWG (Cu), 12-6 AWG (Al) |
| Max Wire | 6 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 |
|---|---|
| Accessories | Load Side Lugs |
| Standards | CSA C22.2 No. 5, NEMA AB 1, UL 489 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
Sold out
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Siemens BQ2B040 - 40A 2 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
| Brand | Siemens |
|---|---|
| Part Number | BQ2B040-R |
| Series | BQ |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | BQ |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens Panelboards (P1, P2, P3) |
| Wire Gauge | 14-6 AWG (Cu), 12-6 AWG (Al) |
| Max Wire | 6 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 |
|---|---|
| Accessories | Load Side Lugs |
| Standards | CSA C22.2 No. 5, NEMA AB 1, UL 489 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
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Description
Operating at a standard 10kAIC rating, the Siemens BQ2B040 delivers essential overcurrent and short-circuit defense for commercial facilities. This 40A, two-pole unit utilizes proven thermal-magnetic trip technology to maintain electrical system integrity. It fastens securely into Siemens P1, P2, and P3 panelboards via a rugged bolt-on connection. Fully HACR rated for HVAC applications, it also functions as a reliable cross-reference alternative for BAB2040 and THQB2140 installations.Specifications
| Brand | Siemens |
|---|---|
| Part Number | BQ2B040 |
| Series | BQ |
| Amperage | 40A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 120/240VAC |
| Phase | 1 |
| AIC Rating | 10kA @ 120/240VAC |
| Frame Type | BQ |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens Panelboards (P1, P2, P3) |
| Wire Gauge | 14-6 AWG (Cu), 12-6 AWG (Al) |
| Max Wire | 6 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 |
|---|---|
| Accessories | Load Side Lugs |
| Standards | CSA C22.2 No. 5, NEMA AB 1, UL 489 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated |
Product FAQs
6 answersWhich panelboards are compatible with the BQ2B040 breaker?
This BQ-frame breaker is engineered specifically for installation in Siemens P1, P2, and P3 series panelboards.
Can the BQ2B040 replace legacy ITE circuit breakers?
Yes. Siemens acquired ITE, and the Siemens BQ2B040 serves as the direct manufacturer replacement for the identical legacy ITE catalog number.
What wire sizes do the terminal lugs accommodate?
The factory-installed lugs are rated for both copper and aluminum. They accept 14 to 6 AWG copper (Cu) conductors and 12 to 6 AWG aluminum (Al) conductors.
How is this breaker mounted into the panel?
The BQ2B040 utilizes a bolt-on connection. It must be mechanically fastened directly to the panelboard bus, providing a highly secure connection that minimizes the risk of loose seating or arcing.
Are the trip parameters on this 40A breaker adjustable?
No, this is a fixed-trip breaker. Both the thermal and magnetic trip thresholds are factory-set and cannot be altered in the field.
What type of fault protection does the LI trip unit provide?
The thermal-magnetic LI (Long-Time, Instantaneous) trip functions protect against two primary electrical hazards. The thermal element prevents damage from sustained overloads, while the magnetic instantaneous element rapidly interrupts severe short circuits.
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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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All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
Reviews
Review summary
Customers rate this product 4.9 out of 5 based on 73 reviews.
Reviews Summary
Generated by AI from 67 most recent customer reviews
Last updated 6/3/26
Customers say these breakers arrive quickly and fit perfectly for their electrical needs. Fast shipping and competitive pricing are frequently mentioned, with many users appreciating the availability of hard-to-find and older-style breakers. The products are well-packaged and arrive in good condition. Most customers report successful installations and reliable performance. A few note missing items from orders or concerns about product condition, though the majority express satisfaction with their purchases and indicate they would order again.
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Rating
73 reviews
- HSHector S.Verified BuyerReviewingSiemens BQ3B100H - 100A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/27/26Perfect replacement
Fit perfectly and good price
- AFAnthony F.Verified BuyerReviewingSiemens BQ2B020 - 20A 2 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/25/26works as expected
works as expected
- MSMike S.Verified BuyerReviewingEaton / Cutler-Hammer BQ250250 - 50/50A Quadplex Miniature Circuit BreakerI recommend this productRated 5 out of 5 stars8/12/26Electrical company
Breaker worked awesome thank you very much
- PEPhilip E.Verified BuyerReviewingSiemens BQ3B020 - 20A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars8/10/26Siemens BQ3B020
The breaker arrived as described and on time. It works as expected. I will order from SuperBreakers again in the future without hesitation.
- PLPaul L.Verified BuyerReviewingSiemens BQ1B020 - 20A 1 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars7/23/26Breaker
Quick shipping. Exact fit.