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Square D LDA36400CU31X Molded Case Circuit Breaker
- 400A
- 3 Pole
- I-Line
Square D
LDA36400CU31X
Molded Case Circuit Breaker
Brand
Square D
SKU
LDA36400CU31X
Quantity
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Square D LDA36400CU31X - 400A 3 Pole Molded Case Circuit Breaker
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Description
Engineered for maximum continuous power, the Square D LDA36400CU31X is a 3-pole, 400A electronic trip molded case circuit breaker. As part of the PowerPacT L-Frame series, it is 100% rated to handle demanding commercial and industrial loads without derating. This MCCB installs into Square D I-Line panelboards and switchboards, utilizing a plug-on design for fast, secure connections. It features a MicroLogic 3.3 trip unit, delivering highly accurate long-time and instantaneous (LI) protection.Specifications
| Brand | Square D |
|---|---|
| Series | LDA |
| Amperage | 400A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 25kA @ 240VAC, 18kA @ 480VAC, 14kA @ 600VAC |
| Amperage Range | 160-400A |
|---|
| Frame Type | LDA |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards, Square D I-Line Switchboards |
| Wire Gauge | 2 x 2/0 AWG - 500 kcmil (Al/Cu) |
| Max Wire | 500 kcmil |
| Min Wire | 2/0 AWG |
| Trip Technology | Electronic Trip |
|---|---|
| Trip Function Code | LI |
| Trip Function | Long-Time, Instantaneous |
| Trip Adjustability | Adjustable |
| Available Options | Shunt Trip, Auxiliary Switch, Undervoltage Release, Alarm Switch, Padlock Attachment, Communication Module |
|---|---|
| Accessories | Lugs |
| Standards | CSA C22.2 No. 5, IEC 60947-2, NEMA AB 1, UL 489 |
| Approval | CE, CSA, IEC, NEMA, NOM, UL |
| Temp Rating | -25C to 70C |
| Construction Features | 100% Rated, HACR Rated, Visual Trip Indicator, True RMS Sensing, RoHS Compliant, Mercury Free |
Product FAQs
8 answersIs the Square D LDA36400CU31X circuit breaker 100% rated?
Yes, the 'C' in the catalog number indicates this breaker is 100% rated. It can carry its full 400A continuous current rating without the standard 80% derating, provided it is installed in an enclosure approved for 100% rated devices.
Which panelboards are compatible with the LDA36400CU31X?
This breaker features an I-Line style plug-on connection and is designed exclusively for use in Square D I-Line panelboards and switchboards. It is not compatible with standard NQ or NF series panels.
What type of trip unit is included with the LDA36400CU31X?
It comes equipped with a MicroLogic 3.3 electronic trip unit. This provides adjustable Long-Time and Instantaneous (LI) protection for precise coordination in commercial and industrial power systems.
What wire sizes are accepted by the load-side lugs on this 400A breaker?
The factory-installed load lugs accept two conductors per phase, ranging from 2/0 AWG to 500 kcmil for either aluminum or copper wire.
Can I use this 3-pole L-frame breaker in a 2-pole application?
Yes, this 3-pole breaker can be safely applied in 2-pole, single-phase applications by utilizing the two outer poles, as is standard practice for Square D molded case circuit breakers.
How does the LDA36400CU31X mount into the panel?
It utilizes Square D's I-Line plug-on mounting system for the line side, which allows the breaker to snap directly onto the panelboard bus assembly. The load side uses standard mechanical lugs for wire termination.
Are the trip settings on the LDA36400CU31X adjustable?
Yes, the MicroLogic 3.3 trip unit features adjustable dials on the front of the breaker. This allows the user to fine-tune the Long-Time pickup and Instantaneous pickup to match the specific requirements of the load and conduct a proper coordination study.
Can the LDA36400CU31X replace an older LA36400 circuit breaker?
Yes, the PowerPacT L-Frame series is the modern replacement for legacy Square D LA and LH frame breakers. Because both utilize the I-Line mounting system, the LDA36400CU31X will physically fit in the same panel space, though it upgrades the protection from thermal-magnetic to an electronic trip unit.
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