Siemens LGB3B040B - 40 A, 600 V, 3-Pole Bolt-On Circuit Breaker | AmpState

The Siemens LGB3B040B is a 40A, 600V, 3-pole bolt-on molded case circuit breaker designed to protect branch circuits with precision in panelboards and load centers. Its three-pole configuration ensures simultaneous disconnection of all phases, delivering safer, more reliable performance for 3-phase electrical systems in a variety of environments.

Key benefits

• Secure bolt-on mounting provides a rigid, vibration-resistant bus connection, reducing loose connections and nuisance trips in demanding installations.
• Thermal-magnetic trip unit delivers stable, repeatable protection by combining thermal overload protection with instantaneous magnetic trip for short circuits.
• 40A at 600V capacity suits a wide range of branch circuits without oversizing components, helping to optimize panelboard layouts.
• OEM compatibility is designed to work with matching Siemens OEM loadcenters and panelboards, ensuring dependable fit and performance.
• Versatile application well-suited for residential, commercial, and light industrial settings, from home electrical panels to small business electrical rooms.

Applications and use cases

• Protect 3-phase equipment such as compressors, pumps, and HVAC components in commercial or light industrial spaces.
• Replace or upgrade existing breakers in Siemens or compatible OEM panelboards to restore reliable branch-circuit protection.
• Integrate into new installations where a robust 3-pole, bolt-on MCCB solution is required for motor or process loads.
• Use in retrofit projects where vibration resistance and secure electrical connections are priorities in demanding environments.

Technical snapshot

• Manufacturer: Siemens
• Part number: LGB3B040B
• Type: Thermal-magnetic molded case circuit breaker
• Amperage rating: 40A
• Voltage rating: 600V
• Number of poles: 3
• Mounting style: Bolt-on
• Primary purpose: Branch circuit overcurrent and short-circuit protection

Installation tips and best practices

• Ensure the breaker is mounted on an appropriate panelboard or load center that is compatible with the LGB3B040B to maintain guaranteed performance.
• Secure the bolt-on connection to maximize bus integrity and minimize the potential for vibration-induced trips in dynamic environments.
• Plan 3-phase protection with a single device that trips all three lines simultaneously, simplifying downstream protection coordination and isolation.