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Eaton / Westinghouse LA3125 Molded Case Circuit Breaker
- 125A
- 3 Pole
- Unit Mount
Eaton / Westinghouse
LA3125
Molded Case Circuit Breaker
Brand
Eaton / Westinghouse
SKU
LA3125
Quantity
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Eaton / Westinghouse LA3125 - 125A 3 Pole Molded Case Circuit Breaker
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Description
Maintaining older electrical systems requires precise components, and the Eaton LA3125 delivers exactly that as a 125A, 3-pole legacy MCCB. This robust L-Frame device provides essential protection for three-phase industrial applications. It integrates perfectly into existing Westinghouse panelboards and Pow-R-Line 4 assemblies. By using this exact-fit replacement, facility managers avoid the downtime of installing the modern JD3125 substitute. It features an adjustable magnetic trip unit.Specifications
| Brand | Eaton / Westinghouse |
|---|---|
| Part Number | LA3125-R |
| Series | LA |
| Amperage | 125A |
| Poles | 3 |
| Mounting Style | Unit Mount |
| Voltage | 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 42kA @ 240VAC, 30kA @ 480VAC, 22kA @ 600VAC, 20kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Westinghouse Panelboards, Eaton Pow-R-Line 4 Panelboards, Switchboards |
| Wire Gauge | (1) 1 AWG-600 kcmil (Al/Cu) or (2) 1 AWG-250 kcmil (Al/Cu) |
| Max Wire | 600 kcmil |
| Min Wire | 1 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 | Lugs |
| Standards | CSA C22.2 No. 5, NEMA AB-1, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Interchangeable Trip Unit |
Product FAQs
7 answersWhat is the modern Eaton equivalent for the legacy Westinghouse LA3125?
The Eaton Series C KD3125 is the direct modern replacement for the legacy Westinghouse LA3125. While both are 125A, 3-pole breakers, the KD frame may require different mounting hardware or strap kits depending on your specific panelboard or switchboard chassis.
Which panelboards are compatible with the LA3125 circuit breaker?
The LA3125 is a bolt-on, unit-mount breaker designed for legacy Westinghouse panelboards, Eaton Pow-R-Line 4 (PRL4) panelboards, and various industrial switchboards. It is a molded case circuit breaker for commercial and industrial distribution and is not compatible with standard residential plug-on load centers.
How does the adjustable magnetic trip function on the LA3125?
The LA3125 features a thermal-magnetic trip unit with a fixed thermal element for standard overload protection and an adjustable magnetic element for short-circuit protection. The magnetic dial allows electricians to adjust the instantaneous trip threshold in the field, which helps coordinate with downstream devices and prevents nuisance tripping from high motor inrush currents.
Can the LA3125 circuit breaker be reverse fed?
Yes. Standard thermal-magnetic LA frame breakers like the LA3125 do not have directional Line and Load markings. Under UL 489 guidelines, breakers without these markings have been evaluated for overcurrent tripping in both directions and are safe for reverse-feed applications, such as generator inputs or back-fed mains.
What are the wire size requirements for the LA3125 lugs?
The standard load-side lugs on the LA3125 accept either one 1 AWG to 600 kcmil conductor or two 1 AWG to 250 kcmil conductors. The terminals are rated for both aluminum and copper wire. Always ensure conductors are rated for 75 degrees Celsius and properly torqued to the manufacturer specifications to prevent thermal failure at the connection point.
Is the LA3125 rated for use in direct current (DC) systems?
Yes, the LA3125 is rated for DC applications up to 250VDC, providing an interrupting capacity of 20kA. When installing this breaker in a DC circuit, ensure the pole configuration and wiring comply with NEC guidelines for DC fault interruption.
What is the physical frame size of the LA3125?
The LA3125 belongs to the legacy Westinghouse L-Frame family, which has a maximum physical capacity of 400 amps. This specific LA3125 model is factory-equipped with a 125A fixed thermal trip unit within that larger 400A footprint.
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Reviews
Review summary
Customers rate this product 5.0 out of 5 based on 13 reviews.
Total 5 star reviews: 13 Total 4 star reviews: 0 Total 3 star reviews: 0 Total 2 star reviews: 0 Total 1 star reviews: 0
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Rating
13 reviews
- RGRobert G.Verified BuyerReviewingSquare D LA36400 - 400A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars7/16/26LA36400
Perfectly boxed and arrived on time. Thanks for the shirt and stickers as well.
- CECraig E.Verified BuyerReviewingEaton / Cutler-Hammer LA3600 - 600A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars10/13/25Westinghouse breaker
Excellent customer service and quick shipping
- CLClifton L.Verified BuyerReviewingSquare D LA36400 - 400A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars9/30/25estimator
Good
- BCBenjamin C.Verified BuyerReviewingEaton / Cutler-Hammer LA3225 - 225A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars8/4/25Refurbished Breaker
Breaker seems to be working great, no complaints from Client
- JMJerry M.ReviewingEaton / Cutler-Hammer LA3400 - 400A 3 Pole Molded Case Circuit BreakerI recommend this productRated 5 out of 5 stars3/14/23Where is my breaker?
Where is my breaker?