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Eaton / Westinghouse HK3125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Panel Mount
Eaton / Westinghouse
HK3125
Molded Case Circuit Breaker
Brand
Eaton / Westinghouse
SKU
HK3125
Quantity
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Eaton / Westinghouse HK3125 - 125A 3 Pole Molded Case Circuit Breaker
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Description
Part of the Series C family, this 125-amp K-Frame molded case circuit breaker provides reliable overcurrent protection for industrial facilities. It is designed to mount into older Westinghouse panelboards and motor control centers. As an exact replacement for discontinued systems, it can be substituted with the newer HKD3125 model if needed. The thermal-magnetic trip unit features fixed thermal and adjustable magnetic settings, delivering a 65kAIC interrupt rating at 480VAC.Specifications
| Brand | Eaton / Westinghouse |
|---|---|
| Part Number | HK3125-R |
| Series | HK |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Panel Mount |
| Voltage | 240VAC, 480VAC, 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 100kA @ 240VAC, 65kA @ 480VAC, 35kA @ 600VAC, 22kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Westinghouse 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, Handle Lock, Motor Operator |
|---|---|
| Accessories | Line and Load Lugs Included |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB-1, UL 489 |
| Approval | CE, CSA, HACR, UL |
| Temp Rating | 40C |
| Construction Features | HACR Rated, High Interrupting Capacity, Interchangeable Trip Unit, Trip-Free Mechanism |
Product FAQs
5 answersWhat enclosures are compatible with the HK3125 circuit breaker?
This K-Frame breaker is designed for installation in legacy Westinghouse and modern Eaton Cutler-Hammer panelboards, switchboards, and motor control centers.
How does the adjustable magnetic trip function work on the HK3125?
The adjustable magnetic trip allows you to tune the instantaneous short-circuit response of the breaker. This helps coordinate with downstream devices and prevents nuisance tripping during motor startups or inrush currents.
Are line and load lugs included with the HK3125, and what are their wire capacities?
Yes, the breaker includes standard line and load lugs that accept aluminum or copper conductors ranging from 3 AWG to 350 kcmil. Proper torque specifications must be followed during installation to ensure a secure connection.
What is the difference between the HK3125 and KD3125 breakers?
Both are 125A, 3-pole K-Frame breakers, but they have different interrupting capacities. The HK3125 is a high-interrupting breaker rated at 65kA at 480VAC, whereas the standard KD3125 is rated at 35kA at 480VAC.
Is the HK3125 interchangeable with modern Eaton Series C breakers?
Yes, the HK3125 is a legacy Westinghouse K-Frame breaker that is directly replaced by the modern Eaton HKD3125. Both share the same physical dimensions and mount into the same panelboards and switchboards.
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