Siemens / ITE K3B125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Bolt-On
Quantity
Siemens / ITE K3B125 - 125A 3 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Maintaining existing electrical infrastructure is straightforward with the Siemens K3B125. This 3-pole, 125A legacy molded case circuit breaker provides essential thermal-magnetic protection for 600VAC commercial and industrial systems. Featuring a rugged bolt-on design, it installs into older ITE and Siemens panelboards without the need for modification. It offers an interchangeable trip unit and a 25kAIC rating at 240VAC, ensuring reliable performance for aging power distribution networks.Specifications
| Brand | Siemens / ITE |
|---|---|
| Part Number | K3B125-R |
| Series | K |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 25kA @ 240VAC, 22kA @ 480VAC, 14kA @ 600VAC |
| Frame Type | K |
|---|---|
| Terminal Type | Lugs |
| For Use With | ITE / Siemens Panelboards and Switchboards |
| Wire Gauge | 4 AWG - 350 kcmil (Al/Cu) |
| Max Wire | 350 kcmil |
| Min Wire | 4 AWG |
| Trip Technology | Thermal Magnetic |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Fixed Thermal, Adjustable Magnetic |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch, Lug Kits |
|---|---|
| Accessories | Lugs Not Included |
| Standards | NEMA AB-1, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Interchangeable Trip |
Product FAQs
5 answersWhat panelboards are compatible with the K3B125 circuit breaker?
The K3B125 is designed for use in legacy ITE and Siemens panelboards and switchboards. Because it is a K-frame breaker, it requires the appropriate panel-specific mounting hardware for bolt-on installation.
What does the LI trip function code indicate on the K3B125?
The LI designation means this thermal-magnetic breaker provides Long-Time overload protection through a fixed thermal element, and Instantaneous short-circuit protection through an adjustable magnetic element.
Why choose the legacy K3B125 instead of a modern Siemens replacement?
The K3B125 serves as an exact physical match for aging ITE and Siemens infrastructure. Sourcing this legacy K-frame breaker allows electricians to replace a failed unit directly without installing retrofit kits or modifying the panelboard.
Can I use aluminum wiring with the K3B125?
Yes, the standard lugs on the K3B125 are dual-rated for both aluminum and copper conductors. The terminals accept wire sizes ranging from 4 AWG up to 350 kcmil.
What does the Green ITE branding mean on the K3B125?
Green ITE refers to the legacy era of ITE circuit breakers before the brand was fully integrated into Siemens. The K3B125 retains this authentic legacy design, making it a direct replacement for original Green ITE installations.
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