Square D | MEF436LSIG | Circuit Breaker | 400A | 600V

Meet Square D MEF436LSIG, a purpose-built circuit breaker engineered for high‑demand electrical systems. With a 400A rating and a 600V maximum, this unit delivers reliable overcurrent protection for large feeders, service entrances, or branch circuits in industrial environments. It's designed for maintenance, retrofit, and replacement work where exact specs matter, ensuring you can keep critical equipment running smoothly.

What makes it work for you

• Precise amperage and voltage ratings: 400A at up to 600V, sized for heavy‑duty circuits that require dependable protection.
• Exact part‑number reference for compatibility: Use MEF436LSIG as the best reference to match with existing Square D installations and enclosures.
• Flexible installation paths: Suitable for retrofit projects, maintenance outages, or replacing worn‑out breakers without extensive panel modification.

Why customers choose this for their facilities

Whether you're upgrading an aging distribution panel, expanding capacity for a new line, or replacing a failed breaker, the MEF436LSIG provides dependable performance with minimal downtime. It’s designed to slot into Square D systems that rely on the MEF family for consistent trip characteristics and coordination with other protective devices.

Use cases and ideal environments

• Industrial plants with high‑current feeders and critical loads
• Maintenance windows where a direct, compatible replacement is required
• Retrofits where upgrading to higher protection is part of a broader electrical modernization

Practical guidance

Important: Before ordering, confirm fit and ratings using the exact part number. The MEF436LSIG is the best reference for compatibility with your Square D gear. If you’re unsure, consult your electrical diagrams or a licensed electrician to verify that 400A and 600V ratings align with your system’s needs.