Siemens LGB3B050B 50A 3P 480V Circuit Breaker | AmpState

Engineered by Siemens, the LGB3B050B is a 50 A, 3-pole circuit breaker designed to deliver reliable circuit protection in panelboards, load centers, and broader electrical distribution networks. Built for everyday electrical work, this unit shines in retrofit projects and maintenance planning where staying with the same part number is essential for spare parts efficiency and system integrity.

Key advantages of the Siemens LGB3B050B

• Three-pole design provides coordinated protection for three-phase circuits with a common trip, simplifying wiring and fault containment.
• 50 ampere rating suits feeders and branch circuits that demand steady current without frequent tripping in typical commercial/industrial loads.
• 480 V voltage rating aligns with many three-phase distribution schemes used in offices, manufacturing, and data centers.
• Retrofit-friendly with a consistent part number, reducing inventory complexity and ensuring compatibility with existing Siemens panelboards and distribution devices.
• Trusted Siemens engineering and robust build quality designed for long-term performance and predictable protection.
• Easy sourcing – available through AmpState, with support to confirm fit if you’re matching a specific part number.

What it protects and where you’ll use it

The LGB3B050B serves as a critical safety device in panelboards, load centers, and distribution networks. It shields three-phase circuits from overloads and short circuits, preserving equipment and reducing the risk of electrical fires. Its 3-pole, 480 V capability makes it well-suited for commercial installations, data rooms, and industrial environments where stable power protection is non-negotiable.

Ideal use cases

• Retrofits where the existing part number must be preserved for compliance or asset management.
• Maintenance planning for facilities with three-phase distributions and Siemens equipment.
• New installations that require a reliable 50 A, 3-pole breaker within 480 V systems.
• Spare-part strategy for service fleets that need consistent, readily available replacements.

Installation and compatibility tips

Before installing, verify that the panelboard or distribution device accepts LGB-series breakers and that the bus configuration matches a three-pole, 480 V protection scheme. Maintain appropriate torque on terminals as specified by Siemens installation guidelines. If you’re replacing an existing LGB3B050B or matching a part number across a serviceable fleet, AmpState can help confirm compatibility to minimize downtime.

Specifications at a glance

• Amperage: 50 A
• Poles: 3
• Voltage: 480 V
• Manufacturer: Siemens
• Part Number: LGB3B050B

Available from AmpState. Need help matching a part number or confirming compatibility? Message us and we’ll help you confirm fit.