Free Shipping Over $99
Eaton / Cutler-Hammer KB3125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Bolt-On
Eaton / Cutler-Hammer
KB3125
Molded Case Circuit Breaker
Brand
Eaton / Cutler-Hammer
SKU
KB3125
Quantity
Shop with Confidence
Add an extra year of protection in your cart.
Eaton / Cutler-Hammer KB3125 - 125A 3 Pole Molded Case Circuit Breaker
Re-Certified
Quantity
Similar Items
100A 3 Pole Molded Case Circuit Breaker
200A 3 Pole Molded Case Circuit Breaker
250A 3 Pole Molded Case Circuit Breaker
Description
Engineered for commercial applications, the Eaton KB3125 provides robust overcurrent protection within a compact K-Frame footprint. This 125A, three-pole device utilizes fixed thermal and adjustable magnetic trip units. Designed for seamless integration, it mounts into legacy Westinghouse CDP panelboards, Eaton Series C enclosures, and switchboards. Rated for 25kAIC at 240VAC, this HACR-rated component ensures dependable performance. It is commonly replaced by the newer JD3125 series.Specifications
| Brand | Eaton / Cutler-Hammer |
|---|---|
| Part Number | KB3125-R |
| Series | KB |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 25kA @ 240VAC, 22kA @ 480VAC, 14kA @ 600VAC, 10kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Westinghouse CDP Panelboards, Eaton Series C Panelboards, Switchboards, Motor Control Centers |
| Wire Gauge | 3 AWG - 350 kcmil (Al/Cu) |
| Max Wire | 350 kcmil |
| Min Wire | 3 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 |
|---|---|
| Accessories | Load Side Lugs |
| Standards | NEMA AB-1, UL 489, CSA C22.2 No. 5 |
| Approval | CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, Interchangeable Trip |
Product FAQs
6 answersWhat panelboards are compatible with the KB3125 circuit breaker?
The KB3125 is a K-Frame breaker designed to fit Eaton Series C panelboards and legacy Westinghouse CDP panelboards. It is also suitable for installation in compatible industrial switchboards and motor control centers.
Can the Eaton KB3125 replace an older Westinghouse KB3125?
Yes. Eaton acquired the Westinghouse distribution equipment division, making the Eaton KB3125 the direct, mechanically and electrically identical replacement for the legacy Westinghouse KB3125.
What does the LI trip function indicate on the KB3125?
The LI designation means this thermal-magnetic breaker provides Long-Time (L) and Instantaneous (I) protection. The thermal overload (Long-Time) is fixed at 125 amps, while the magnetic short-circuit (Instantaneous) trip setting is adjustable, allowing electricians to fine-tune the response for specific inrush currents.
What are the conductor size limits for the KB3125 lugs?
The factory-installed lugs accept aluminum or copper (Al/Cu) wire ranging from 3 AWG to 350 kcmil. When terminating conductors, always apply the specific torque value printed on the breaker faceplate to ensure a secure connection and prevent thermal issues.
Is the KB3125 rated for direct current (DC) systems?
Yes, alongside its standard AC ratings up to 600VAC, the KB3125 is certified for use in DC applications up to 250VDC, providing a 10kA interrupting capacity for those circuits.
How does the KB3125 mount into the panel?
The KB3125 is a bolt-on molded case circuit breaker. It secures directly to the panelboard or switchboard bus using bolted connections, which provides a highly reliable, low-resistance joint suitable for demanding 125A commercial and industrial loads.
SuperClub
Join free. Get 500 SuperPoints.
Earn points on eligible purchases and redeem them at checkout.
100 SuperPoints = $1 off.
Warranties
Add an extra year of protection
60-Day Warranty
Your purchase includes 60 days of SuperBreakers warranty coverage.
Add a 1-year warranty extension in your cart.
Get a Quote
Don’t see what you’re looking for?
We source obsolete and hard-to-find parts every day.
Shipping
Free Shipping Policy
Parcel shipments with item value over $99 qualify for free economy shipping within the continental US. Please call to confirm special handling instructions. We do not charge a handling fee or require a minimum amount on any order. SuperBreakers does not ship on customer accounts.
Same Day Shipping
We strive to ship out your items the same day the order is placed. In rare circumstances SuperBreakers may reserve up to 5 business days to consolidate orders for complete shipment.
Expedited Shipments
Orders being shipped via Next Day Air, 2 Day Shipping or 3 Day Shipping must be received by 3 PM EST to guarantee same-day shipments. Expedited orders only ship on normal business days. Shipments will NOT be sent out on Saturdays and Sundays.
International Shipping
All International orders require a $1,000 minimum order threshold. Due to the special nature of these shipments, we require that these be placed with a SuperBreakers representative. Additional shipping and instructions will apply. All International Orders are Non-Cancel and Non-Refundable.
Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 3 reviews.
Total 5 star reviews: 3 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
Search
Rating
3 reviews
- DHDavid H.ReviewingEaton / Cutler-Hammer KB3100 - 100A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars4/21/23very easy to order and
very easy to order and received order promptly
- KLKelsee L.ReviewingEaton / Cutler-Hammer KB3250 - 250A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars5/29/21Excellent
Excellent
- BSBill S.ReviewingEaton / Cutler-Hammer KB3200 - 200A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars6/26/19electrical contractor
no hassle, good product that has been recertified. very satisfied with the result!