Square D QMBFAW 100A 3-Pole 600 V Circuit Breaker Potential Transformer

Meet the Square D QMBFAW 100A 3-Pole 600 V Circuit Breaker Potential Transformer—a purpose-built protection and metering solution designed for demanding commercial and industrial electrical environments. This unit combines robust overcurrent protection with integrated potential-transformer capabilities for accurate sensing in one compact package, helping you streamline panel layouts and improve system reliability.

• Current rating: 100 A
• Poles: 3
• Voltage rating: 600 V
• Part number / model: QMBFAW
• Brand heritage: Square D

Why this combination matters: a three-pole configuration provides balanced protection across all phases in 3-phase systems, reducing the risk of unbalanced faults and improving coordination with downstream protections. The 600 V rating supports mid- to high-voltage applications common in manufacturing floors, distribution panels, and large commercial facilities. The built-in potential-transformer capability enables metering and protection schemes without adding extra big-box components, helping you simplify wiring, shorten installation times, and maintain clean, code-compliant panel interiors.

Optimal use cases

• Protection and monitoring in 3-phase distribution panels and switchgear
• Metering-ready protection for facilities where precise voltage and current data is essential
• Replacement or upgrade in existing Square D installations to maintain system integrity
• Applications requiring a compact, single-unit solution that combines protection with measurement

Practical advantages you’ll notice

• Consolidates protection and metering functionality, reducing wiring complexity and panel clutter
• Three-pole design delivers symmetric protection across all phases, enhancing fault isolation
• Durable construction suitable for industrial environments and long service life
• Clear part identification (QMBFAW) supports efficient procurement and maintenance workflows

If you’re an electrical contractor, panel builder, or facility manager, this Square D unit offers a reliable, measurement-ready solution that aligns with standard 3-phase electrical architectures. Ensure compatibility with your existing panel hardware and follow appropriate safety practices during installation to maximize performance and longevity.