Square D KC34125-1021 Molded Case Circuit Breaker
- 125A
- 3 Pole
- I-Line
Quantity
Square D KC34125-1021 - 125A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Built for advanced control, the Square D KC34125-1021 includes a factory-installed shunt trip for remote disconnect capabilities. This 3-pole, 125A breaker utilizes thermal-magnetic trip technology with long-time and instantaneous (LI) functions. Designed for commercial distribution, it installs into Square D I-Line panelboards and switchboards. For facilities transitioning to newer equipment, this K-Frame unit is replaced by the JJA36125SA. It features an extra-high 65kAIC rating at 480VAC.Specifications
| Brand | Square D |
|---|---|
| Series | KC |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480VAC, 10kA @ 250VDC |
| Frame Type | K |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards and Switchboards |
| Wire Gauge | 4 AWG - 350 kcmil |
| 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 | Auxiliary Switch, Alarm Switch, Undervoltage Release |
|---|---|
| Accessories | Load Side Lugs Included, Shunt Trip (Factory Installed) |
| Standards | CSA C22.2 No. 5, NEMA AB 1, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Extra High Interrupting Capacity |
Product FAQs
6 answersWhat does the "-1021" suffix mean on the KC34125-1021?
The "-1021" suffix indicates that this breaker includes a factory-installed 120-240VAC shunt trip. This accessory allows the breaker to be tripped remotely by applying a voltage signal to the shunt trip coil, which is commonly used for emergency stops or automated control systems.
What is the modern replacement for the KC34125-1021?
The legacy K-Frame KC34125 is replaced by the Square D PowerPact J-Frame series, specifically the JJA36125. Because this specific model includes a 120-240VAC shunt trip, any PowerPact replacement must also be equipped with a 120VAC shunt trip accessory to maintain remote tripping capabilities.
What type of panels are compatible with the KC34125-1021?
This breaker features an I-Line style plug-in connection and is designed exclusively for use in Square D I-Line panelboards and switchboards. It mounts directly to the busbar stack and is not compatible with standard QO, Homeline, or NQ/NF series panels.
What wire sizes are accepted by the lugs on this breaker?
The standard lugs on the KC34125-1021 accept wire gauges from 4 AWG up to 350 kcmil. Ensure proper torque specifications are followed during installation to maintain a secure connection and prevent thermal issues.
Can the trip settings on the KC34125-1021 be adjusted?
Yes, this thermal-magnetic breaker features an adjustable magnetic trip for instantaneous short-circuit protection. While the thermal overload protection is fixed at 125 amps, the magnetic trip threshold can be adjusted using the dial on the front of the breaker to coordinate with downstream devices.
Is the KC34125-1021 suitable for DC applications?
Yes, in addition to its AC ratings, this breaker is rated for use in DC circuits up to 250VDC, where it provides an interrupting capacity of 10kA.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 1 review.
- TDTammy D.Verified BuyerReviewingSquare D KC34200 - 200A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars7/9/26Breakers
great service!! I had bought 3 different breakers & there was one that i had to return. I called as soon as i realized it was wrong.( my fault) I had my return RMA in about 5 minutes of the phone call. Highly recommend!!