Siemens / ITE CK3B125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Bolt-On
Quantity
Siemens / ITE CK3B125 - 125A 3 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Description
Part of the legacy Cordon series, the Siemens CK3B125 is a 3-pole, 125A molded case circuit breaker for commercial power distribution. It delivers reliable thermal-magnetic protection for critical loads. This bolt-on unit installs into older Siemens and ITE panelboards. It serves as an exact physical match for aging infrastructure and is replaced by CFD63B125 frames when upgrading. Rated 100kAIC at 480VAC, its integrally fused design restricts let-through energy to safeguard equipment.Specifications
| Brand | Siemens / ITE |
|---|---|
| Part Number | CK3B125-R |
| Series | CK |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 200kA @ 240VAC, 100kA @ 480VAC, 100kA @ 600VAC |
| Frame Type | CK |
|---|---|
| Terminal Type | Lugs |
| For Use With | Siemens/ITE Panelboards and Switchboards |
| Wire Gauge | 4 AWG - 300 kcmil (Cu), 2 AWG - 300 kcmil (Al) |
| Max Wire | 300 kcmil |
| 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, Undervoltage Release, Alarm Switch |
|---|---|
| Accessories | Line and Load Lugs Included |
| Standards | UL 489, NEMA AB-1, CSA C22.2 No. 5 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Current Limiting |
| Special Features | Current Limiting |
Product FAQs
5 answersWhich panelboards are compatible with the CK3B125 breaker?
This bolt-on breaker is designed for use in legacy Siemens and ITE panelboards or switchboards configured to accept C-frame molded case circuit breakers. Verify your panel interior and busbar spacing accommodate the CK frame footprint before installation.
How does the current limiting feature of the CK3B125 benefit my electrical system?
As a current limiting breaker, it clears high-level short circuits extremely fast, typically in less than a half cycle. This rapid clearing reduces the peak let-through current and thermal energy, providing enhanced protection for downstream wiring and equipment.
Can I use this Siemens breaker to replace an older ITE CK3B125?
Yes. Siemens acquired ITE and continued manufacturing many of their legacy designs. A Siemens CK3B125 is a direct, drop-in replacement for an original ITE breaker with the exact same catalog number.
What type of conductors can be used with the lugs on this breaker?
The factory lugs are dual-rated for both copper and aluminum conductors. While it accepts 4 AWG to 300 kcmil copper or 2 AWG to 300 kcmil aluminum, installers must verify that the wire bending space in the enclosure complies with NEC requirements for these larger conductors.
Is the trip unit on this breaker adjustable?
No. The CK3B125 features a fixed thermal and fixed magnetic trip unit. It provides standard long-time and instantaneous protection functions without user-adjustable dials, meaning the trip curve is factory set for 125A applications.
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