Siemens KL3B400 400A 3-Pole 600 V Circuit Breaker

Meet the Siemens KL3B400 400A 3-Pole 600 V Circuit Breaker—a robust protection device engineered for demanding 3-phase power systems. With a 400 A current rating and three poles, it reliably interrupts fault currents to shield wiring, motors, and controls in industrial and commercial environments. Part Number KL3B400, this breaker is built to support serious load demands while keeping your electrical distribution safe and compliant.

• Current rating: 400 A
• Poles: 3
• Voltage rating: 600 V
• Part number: KL3B400
• Brand: Siemens
• Application: protections for 3-phase circuits in industrial and commercial power distribution

The KL3B400 is designed for heavy-duty feeders in three-phase systems up to 600 V, making it an ideal main service disconnect or feeder protection in manufacturing plants, large facilities, and data-center infrastructure. Its three-pole construction ensures synchronized disconnection across all phases, preserving system integrity and reducing the risk of equipment damage during faults.

Key benefits include:

• Reliable three-phase protection that shuts down all phases simultaneously in fault conditions
• High current capability suited for substantial feeders and motor loads
• 600 V compatibility designed for common industrial and commercial power distribution schemes
• Seamless integration with existing Siemens panel and protection ecosystems, supporting consistent performance across your electrical infrastructure

Who should consider the KL3B400? electrical engineers, maintenance teams, and installers responsible for safe, up-to-date power distribution in facilities with three-phase 600 V service. This breaker helps reduce downtime by quickly isolating faults, protects wiring and equipment from overload damage, and supports compliant, maintainable electrical systems.

Practical notes: verify that your panel or distribution board accepts KL-series breakers, plan for a 400 A, 3-pole, 600 V device in your design, and follow local electrical codes during installation. For ongoing operations, pair the KL3B400 with routine fault-current checks and preventive maintenance to maximize uptime and safety.