Square D LE3400U31X 400A 3-Pole 600 V Circuit Breaker

The Square D LE3400U31X is engineered for serious electrical protection in demanding environments. With a 400 A rating, 3 poles, and a 600 V maximum, this circuit breaker delivers reliable overcurrent protection for three‑phase feeders and heavy-duty equipment in industrial and commercial panels. Part of Square D’s trusted LE series, the LE3400U31X is built to fit compatible Square D installations and provide quick, dependable interrupting performance when it matters most.

Why the LE3400U31X matters

• High-current reliability: 400 A capacity protects large feeders and motor circuits without frequent trips.
• Three-pole design: Ideal for balanced three-phase systems, reducing single-phase imbalances and simplifying wiring in 3‑phase layouts.
• 600 V rating: Suitable for modern industrial and commercial distribution environments, offering appropriate protection for common high-voltage applications.
• Durable lineage: Part of Square D’s established LE series, known for dependable performance in demanding installations.
• Replacement-ready: A practical, drop-in option for panels that specify LE3400U31X, helping minimize downtime during maintenance or upgrades.

Ideal use cases

• Main service disconnects or feeder protection in commercial buildings with three‑phase power.
• Motor control applications in manufacturing or processing facilities handling large loads.
• Backup or critical-load circuits where consistent, predictable trip characteristics are essential.

Installation and compatibility

Place the LE3400U31X in compatible Square D panels designed for LE-series breakers. Before installation, confirm that the panel accepts the LE3400U31X form factor and that the system’s voltage and conductor sizing align with the 600 V rating and 400 A protection level. This model is designed for straightforward replacement in established Square D configurations, helping technicians minimize panel downtime during service or upgrades.

Maintenance and longevity

For enduring performance, routinely inspect connections for tightness and signs of wear, and replace any breaker showing corrosion or physical damage. Keeping spare LE3400U31X units on hand can reduce downtime and keep critical processes online during planned maintenance or unexpected outages.

Specifications at a glance

• Current rating: 400 A
• Poles: 3
• Voltage rating: 600 V
• Part number: LE3400U31X
• Manufacturer: Square D