Square D QMBKA3 225A 3-Pole 600 V Circuit Breaker Potential Transformer

Power reliability and measurement accuracy go hand in hand with the Square D QMBKA3 225A 3-Pole 600 V Circuit Breaker Potential Transformer. Engineered for tough industrial environments, this module combines robust overcurrent protection with a built-in potential transformer to deliver essential voltage sensing directly at the point of protection.

Key advantages

• 225 Amp current rating designed to handle high-load feeders and motor circuits in three-phase systems.
• Three poles for reliable three-phase protection with coordinated trip behavior.
• 600 V voltage rating suitable for common electrical distribution in industrial facilities.
• Integrated potential transformer enables accurate voltage measurement and metering for protective relays and monitoring devices, reducing additional wiring and components.
• Space-saving installation minimizes panel complexity by combining protection and sensing in one unit.

What problems does it solve?

Low-profile, combined protection and voltage sensing helps you:

• Reduce wiring clutter and installation time in switchgear and panelboards.
• Improve measurement accuracy by placing the sensing element close to the protected circuit.
• Streamline protection schemes that rely on voltage feedback for relays and monitoring equipment.

Ideal use cases

• Three-phase feeder circuits in manufacturing plants, data centers, and utility rooms.
• Motor control centers needing integrated metering for energy management.
• Panels requiring coordinated protection and voltage sensing without external potential transformers.

Practical tips

• Verify compatibility with your panel or switchgear’s bus arrangement and conductor sizing for 225 A circuits.
• Plan for voltage sensing wiring to the protection/monitoring devices that will utilize the potential transformer output.
• Consider spare units or replacement parts with the same model number for consistent protection characteristics.

With the Square D QMBKA3, you’re not just protecting a circuit—you’re enabling precise monitoring and smarter protection strategies across your electrical distribution. If you’re upgrading an existing panel or designing a new installation that demands reliable three-pole protection at 600 V with integrated sensing, the QMBKA3 stands out as a practical, purpose-built solution.