Square D | LRA36400U31X | Circuit Breaker | 400A | 3-Pole | 600V | Plug-In

Meet the Square D LRA36400U31X circuit breaker — a 400A, 3-pole, 600V plug-in protection device designed for fast, reliable service in Square D electrical systems. Built for maintenance, retrofit, and replacement projects where exact specs matter, this unit slips into compatible panels with minimal downtime, helping you keep critical systems online when it matters most.

Key specifications

• Amperage: 400 A
• Poles: 3-Pole
• Voltage: 600 V
• Mounting: Plug-In
• Part number: LRA36400U31X

Why this plug-in breaker stands out

Designed specifically for Square D panels, the LRA36400U31X delivers a direct-fit, plug-in installation that minimizes downtime during maintenance or replacements. Its 400A rating provides robust protection for feeders and downstream equipment, while the 3-pole configuration ensures balanced protection across phases in 600V systems. Because the part number is the best reference for compatibility, you can trust this unit to match your panel’s listing and interrupting requirements when you confirm fit and ratings before ordering.

Ideal use cases

• Maintenance: quick swap for a failed or aging breaker to restore system protection without extensive downtime.
• Retrofit: upgrade or replace existing breakers in compatible Square D panels to maintain safety margins and system performance.
• Replacement: dependable, ready-to-install solution for panels requiring a 400A, 3-pole, 600V plug-in breaker.

Fit, compatibility, and safety considerations

Before purchasing, confirm that your panel accepts a plug-in 400A, 3-pole 600V device and that the LRA36400U31X is listed for your specific application. The part number itself is the most reliable compatibility reference. Always verify panel labeling, listing, and required interrupting rating to ensure a safe, code-compliant installation.

Practical tips for installation and longevity

• Power down the panel and follow lockout/tagout procedures before handling any breaker.
• Inspect bus contacts and the surrounding area for cleanliness and corrosion; clean if necessary to ensure a solid, fault-free connection.
• Keep a labeled spare on hand for rapid response during critical maintenance windows.
• Document the replacement with the exact part number (LRA36400U31X) to simplify future service and ordering.

With its precise specifications, plug-in design, and focus on compatibility, the Square D LRA36400U31X is a purpose-built solution for reliable protection in 600V, 400A feeding applications. It’s the targeted replacement option that helps maintenance teams and facilities managers minimize downtime while safeguarding essential electrical infrastructure.