Square D KC34250-1021 Molded Case Circuit Breaker
- 250A
- 3 Pole
- I-Line
Quantity
Square D KC34250-1021 - 250A 3 Pole Molded Case Circuit Breaker
New
Quantity
Description
Designed for advanced control applications, this 250A thermal-magnetic circuit breaker includes a built-in 120-240VAC shunt trip mechanism. It integrates seamlessly into Square D I-Line panelboards, providing both overcurrent protection and remote shutdown capabilities. The extra-high 100kA interrupting rating at 240V ensures reliable performance during severe fault conditions. For modernizations, engineers typically specify the JJA36250 as the current-generation replacement base unit.Specifications
| Brand | Square D |
|---|---|
| Part Number | KC34250-1021 |
| Series | KC |
| Amperage | 250A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480Y/277VAC, 480VAC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480Y/277VAC, 65kA @ 480VAC |
| 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, Undervoltage Release, Alarm Switch, Padlock Attachment |
|---|---|
| Accessories | Lugs (AL250KA), Shunt Trip (120-240VAC) |
| 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, Non-Interchangeable Trip, Trip-Free Mechanism, Quick-Make/Quick-Break |
Product FAQs
7 answersWhat panelboards are compatible with the KC34250-1021 circuit breaker?
This breaker features a plug-in mounting style designed exclusively for Square D I-Line panelboards and switchboards. It utilizes a specialized busbar connection and will not fit standard QO, NQ, or NF load centers.
What does the -1021 suffix indicate on the KC34250-1021 catalog number?
The -1021 suffix designates a factory-installed 120/240VAC shunt trip accessory. This allows the breaker to be tripped remotely via an external control signal, which is commonly used for emergency stops or automated shutdown systems.
What type of wire can I use with the KC34250-1021 lugs?
The factory lugs on this 250A breaker accept 4 AWG to 350 kcmil conductors. Ensure you torque the lugs to the manufacturer specifications printed on the breaker label to maintain a secure connection and prevent overheating.
How does the adjustable magnetic trip work on the KC34250-1021?
While the thermal overload protection is fixed at 250A, the magnetic instantaneous trip setting can be adjusted. This allows electricians to fine-tune the short-circuit response threshold to coordinate with downstream breakers and prevent nuisance tripping from motor inrush currents.
Is the KC34250-1021 a current production model?
The KC34250-1021 belongs to the legacy Square D K-Frame series. While the original K-Frame has been largely superseded by the PowerPact J-Frame series in new installations, this breaker remains a direct replacement for existing I-Line K-Frame applications without requiring panel modifications.
What is the modern equivalent for the KC34250-1021 if I am upgrading my panel?
For new infrastructure, the PowerPact JJA36250 serves as the manufacturer recommended replacement for the 250A, 65kAIC K-Frame. Note that you will need to add a separate shunt trip accessory to the J-Frame to replicate the -1021 functionality.
Does the KC34250-1021 include auxiliary switches or alarm contacts?
No, the -1021 suffix only indicates the presence of a 120/240VAC shunt trip. If you require auxiliary switches or alarm contacts, you will need a different catalog number or additional field-installable accessories if supported by the legacy frame.
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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!!