Square D | MA264001121 | Circuit Breaker | 400A | 3-Pole | 600V

The Square D MA264001121 Circuit Breaker is a high-capacity protection device designed for demanding 3‑phase electrical systems. With a 400 A rating across 3 poles and a 600 V operating capability, this unit is built to safeguard large commercial and industrial circuits from overloads and short circuits while keeping power flowing safely to critical equipment.

This breaker is specifically suitable for maintenance, retrofit, and replacement projects where exact specifications matter. When your panel or distribution setup requires an MA264001121‑type device, this unit delivers a reliable, compatible solution that fits the intended electrical architecture.

Note: Confirm fit and ratings before ordering. The part number MA264001121 is the best reference for compatibility.

Key specifications at a glance

• Amperage: 400 A
• Poles: 3-Pole (three-phase protection)
• Voltage rating: 600 V
• Part number: MA264001121

Why this unit stands out

Choosing the MA264001121 means aligning with a proven Square D design that supports robust protection for three-phase feeders. Its 400 A capacity is well-suited for main or large branch circuits, helping to prevent outages in material handling lines, processing equipment, or critical manufacturing controls. The 3-pole configuration ensures simultaneous shutdown of all phases, reducing risk during fault conditions and simplifying safe maintenance.

Ideal use cases

• Maintenance: replacing aging or failed breakers in existing Square D installations where 3‑pole, 600 V protection is required.
• Retrofit: upgrading panel protection to accommodate higher current demands in commercial or light industrial environments.
• Replacement: exact-match replacement for systems specifying MA264001121 to maintain electrical system continuity and compatibility.

Practical guidance for installation and compatibility

• Always verify the panel labeling and service ratings to ensure 400 A, 3‑pole, and 600 V compatibility.
• Use the part number MA264001121 as the definitive reference when sourcing spares or performing replacements.
• For safe handling, shut off power, use appropriate personal protective equipment, and follow electrical code requirements during installation or replacement.