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Eaton / Westinghouse LM3400 Molded Case Circuit Breaker
- 400A
- 3 Pole
- Bolt-On
Eaton / Westinghouse
LM3400
Molded Case Circuit Breaker
Brand
Eaton / Westinghouse
SKU
LM3400
Quantity
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Eaton / Westinghouse LM3400-R - 400A 3 Pole Molded Case Circuit Breaker
Re-Certified
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Description
Delivering reliable thermal-magnetic protection, the Eaton LM3400 is a 400A, 3-pole Series C L-Frame MCCB. It serves commercial facilities requiring robust electrical defense. This unit installs into legacy Westinghouse panelboards and motor control centers without aftermarket adapters. Serving as an exact fit for aging infrastructure, it is often replaced by KD3400 or LD3400 models today. Featuring an interchangeable trip unit and 25kAIC at 240V, it handles demanding industrial loads.Specifications
| Brand | Eaton / Westinghouse |
|---|---|
| Part Number | LM3400-R |
| Series | LM |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | Bolt-On |
| Voltage | 600VAC, 250VDC |
| Phase | 3 |
| AIC Rating | 25kA @ 240VAC, 18kA @ 480VAC, 14kA @ 600VAC, 10kA @ 250VDC |
| Terminal Type | Lugs |
|---|---|
| For Use With | Westinghouse Panelboards, Switchboards, Motor Control Centers |
| Wire Gauge | (2) 3/0 AWG - 250 kcmil |
| Max Wire | 250 kcmil |
| Min Wire | 3/0 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 | CSA C22.2 No. 5, NEMA AB-1, UL 489 |
| Approval | CSA, UL |
| Temp Rating | 40C |
| Construction Features | Interchangeable Trip Unit |
Product FAQs
8 answersWhat equipment is compatible with the LM3400?
This breaker is designed to install directly into legacy Westinghouse and Eaton Cutler-Hammer panelboards, switchboards, and motor control centers that accept Series C L-Frame breakers.
What does the adjustable magnetic trip on this breaker allow?
The adjustable magnetic setting lets electricians customize the instantaneous short-circuit response threshold. This helps coordinate the breaker with other protective devices in the electrical system to prevent nuisance tripping.
Is the Eaton LM3400 identical to the original Westinghouse LM3400?
Yes. Eaton acquired the Westinghouse electrical distribution line, so the Eaton LM3400 is the exact same breaker and serves as a direct drop-in replacement for older Westinghouse units.
What is the modern equivalent or replacement for the LM3400?
The Eaton LD3400 is often used as a modern replacement for the LM3400 in Series C L-Frame applications, providing the same physical footprint and thermal-magnetic protection.
Does the LM3400 require aftermarket adapters to fit older Westinghouse switchboards?
No. It is an exact fit for aging Westinghouse infrastructure and mounts using the standard bolt-on configuration without the need for retrofit kits or custom bus adapters.
Can the trip unit on the LM3400 be swapped out?
Yes, the LM3400 features an interchangeable trip unit design. This allows panel builders to replace or upgrade the thermal-magnetic trip functions without removing the entire breaker frame from the enclosure.
Why must the available fault current be verified before installing the LM3400?
Installing a breaker with an interrupting rating lower than the available fault current can result in catastrophic failure during a short circuit. Always ensure the LM3400's specific AIC ratings meet or exceed your system's maximum fault current at the operating voltage.
Are load side lugs included with this breaker?
Yes, the LM3400 comes complete with factory-installed load side lug terminals, allowing for immediate wire termination upon installation.
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