Square D LDA36250U31X Molded Case Circuit Breaker
- 250A
- 3 Pole
- I-Line
Square D
LDA36250U31X
Molded Case Circuit Breaker
Brand
Square D
SKU
LDA36250U31X
Quantity
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Square D LDA36250U31X - 250A 3 Pole Molded Case Circuit Breaker
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Description
Built for demanding industrial environments, the Square D LDA36250U31X is a 3-pole, 250A electronic trip circuit breaker from the PowerPacT L-Frame family. Designed for seamless integration, this breaker mounts into Square D I-Line panelboards and switchboards. The plug-on I-Line connection ensures rapid installation and secure phase connections. Rated for 18 kAIC at 480V, this 80% rated MCCB features a MicroLogic 3.3 trip unit for adjustable long-time and instantaneous (LI) protection.Specifications
| Brand | Square D |
|---|---|
| Series | LDA |
| Amperage | 250A |
| Poles | 3 |
| Mounting Style | I-Line |
| Voltage | 240VAC, 480VAC, 600VAC |
| Phase | 3 |
| AIC Rating | 25kA @ 240VAC, 18kA @ 480VAC, 14kA @ 600VAC |
| Amperage Range | 100-250A |
|---|
| Frame Type | L |
|---|---|
| Terminal Type | Lugs |
| For Use With | Square D I-Line Panelboards, Square D I-Line Switchboards |
| Wire Gauge | 2 AWG - 500 kcmil (Al), 2 AWG - 600 kcmil (Cu) |
| Max Wire | 600 kcmil |
| Min Wire | 2 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, Motor Operator |
|---|---|
| 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 | HACR Rated, 80% Rated |
Product FAQs
7 answersWhat enclosures and panels accept the LDA36250U31X breaker?
This breaker is specifically designed for Square D I-Line panelboards and switchboards. It will not fit in standard QO, NQ, or NF series panels, nor can it be used as a standalone unit-mount breaker without the proper I-Line bus assembly.
What specific trip unit is included with the U31X designation?
The U31X suffix indicates the breaker is equipped with a MicroLogic 3.3 electronic trip unit. This provides adjustable Long-Time and Instantaneous (LI) protection, allowing for precise coordination in commercial and industrial power systems.
How is the LDA36250U31X secured inside the panel?
It utilizes the Square D I-Line plug-on mounting system. The breaker features jaw-like connectors that push directly onto the panelboard bus stack, secured by a mounting bracket. This eliminates the need for bolted bus connections and speeds up installation.
How do I adjust the trip settings on the MicroLogic 3.3 unit?
The Long-Time and Instantaneous pickup settings are adjusted using the rotary dial switches located directly on the front face of the trip unit. A small flathead screwdriver is required to dial in the specific amperage requirements dictated by your coordination study.
Does the MicroLogic 3.3 trip unit require an external power supply to operate?
No, the MicroLogic 3.3 is a self-powered electronic trip unit. It draws the necessary operating current directly from the phase conductors it protects, ensuring reliable tripping even if external control power is lost.
Is the LDA36250U31X a direct replacement for older Square D L-Frame breakers?
Yes, this PowerPacT L-Frame breaker can replace older legacy Square D L-Frame I-Line breakers of the same amperage and interrupting capacity. Verify that your existing panel has the required I-Line bus spacing to accommodate the modern PowerPacT dimensions.
What does the D signify in the LDA36250U31X catalog number?
The D indicates the specific interrupting rating tier for this PowerPacT frame. For this model, the D-tier provides a maximum interrupting capacity of 25kA at 240VAC, 18kA at 480VAC, and 14kA at 600VAC.
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