Siemens EF2B125 Molded Case Circuit Breaker
- 125A
- 2 Pole
- Bolt-On
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Siemens EF2B125 - 125A 2 Pole Molded Case Circuit Breaker
Re-Certified
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Description
Designed to safeguard electrical infrastructure, the Siemens EF2B125 is a 2-pole, 125A molded case circuit breaker. This bolt-on unit provides essential long-time and instantaneous protection for 600VAC systems. Compatibility includes Siemens P1, P2, and P3 panelboards alongside legacy I-T-E hardware. For maintenance planning, the ED62B125 serves as the direct modern replacement.Specifications
| Brand | Siemens |
|---|---|
| Part Number | EF2B125 |
| Series | EF |
| Amperage | 125A |
| Poles | 2 |
| Mounting Style | Bolt-On |
| Voltage | 600VAC, 250VDC |
| Phase | 1 |
| AIC Rating | 18kA @ 240VAC, 14kA @ 480VAC, 14kA @ 600VAC, 10kA @ 250VDC |
| Frame Type | EF |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens P1, P2, P3 Panelboards, Legacy I-T-E Panelboards |
| Wire Gauge | 4-3/0 AWG (Cu/Al) |
| Max Wire | 3/0 AWG |
| 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, Alarm Switch, Undervoltage Release |
|---|---|
| Accessories | Load Side Lugs Included |
| Standards | UL 489, CSA C22.2 No. 5 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Non-Interchangeable Trip |
Product FAQs
7 answersWhat panelboards are compatible with the EF2B125?
This breaker bolts directly into Siemens P1, P2, and P3 panelboards. It is also fully backward compatible with older legacy I-T-E panelboard chassis, allowing you to maintain existing infrastructure without a full retrofit.
What is the modern replacement for the EF2B125?
The Siemens ED62B125 is the direct modern replacement for this legacy EF frame breaker. It shares the same footprint and mounting configuration for a straightforward drop-in upgrade.
What wire sizes are accepted by the lugs on this breaker?
The included load-side lugs accept copper or aluminum conductors ranging from 4 AWG to 3/0 AWG. Always ensure connections are torqued to the manufacturer specifications printed on the breaker face.
Can this breaker be used in DC power systems?
Yes, in addition to its AC ratings, this breaker is rated for up to 250VDC applications. It provides a 10kAIC interrupting rating for direct current circuits.
Does this breaker mount to a standard DIN rail?
No, this is a bolt-on molded case circuit breaker designed specifically for panelboard chassis mounting. It is not compatible with DIN rail installations.
Can I use this to replace an older I-T-E branded EF frame breaker?
Yes. Siemens acquired I-T-E and maintained the same physical footprint for the EF frame. This unit will directly replace older I-T-E breakers that share the same catalog number.
How does the trip mechanism protect the circuit?
It features a thermal-magnetic trip unit with fixed settings. The thermal component provides long-time protection against sustained overloads, while the magnetic component offers instantaneous protection to safely clear short circuits.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 2 reviews.
- VGVictor G.Verified BuyerRated 5 out of 5 stars11/6/25Breakers fit my needs
I wish I would of shopped this I found exact breaker for 400.00 cheaper
- RFRobert F.ReviewingSiemens EF3A100 - 100A 3 Pole Motor Circuit ProtectorI recommend this productRated 5 out of 5 stars7/25/22Fast order and service for a part in good condition
Fast order and service for a part in good condition.